1 Scope
NOTE This standard covers the materials, installation, testing, and commissioning of underground automatic landscape irrigation systems that distribute water from a defined point of connection to turf, planting beds, trees, and other landscape areas through buried piping, automatic valves, sprinkler heads, rotors, and drip or micro-irrigation devices under the control of an automatic controller. (1.1)
NOTE The scope begins at the downstream side of the irrigation point of connection — immediately downstream of the irrigation meter, isolation valve, and backflow prevention assembly — and extends through the mainline, zone control valves, lateral piping, emission devices, and the low-voltage control wiring and controller that operate the system. (1.2)
NOTE Landscape irrigation is the site scope most directly responsible for the long-term survival of the landscape investment and for the project's water-efficiency performance. An irrigation system that is poorly zoned, that mixes incompatible emission devices on a single valve, or that applies water faster than the soil can absorb it does not fail dramatically — it fails by producing dry spots and runoff at the same time, by over-watering some hydrozones while under-watering others, and by consuming far more water than the landscape requires. Because water is metered and, increasingly, restricted by local purveyors and drought ordinances, the efficiency of the installed system is a continuing operating cost to the Owner for the life of the landscape. This standard establishes the material quality, the zoning and coverage principles, and the installation and testing protocols within which the irrigation design drawings operate. (1.3)
NOTE This standard does not include the hydraulic design of the irrigation system. The irrigation designer or landscape architect of record establishes the water demand, the hydrozone layout, the head and emitter selection and spacing, the zone valve grouping, the pipe sizing, the controller program, and the point-of-connection sizing. (1.4)
1.6The Contractor shall install the system as designed.
1.7The Contractor shall report to the designer of record any field condition that would prevent the designed system from being constructed as drawn — including inadequate static pressure or flow at the point of connection, conflicts with other utilities, insufficient cover, or coverage gaps created by hardscape or planting changes made after the irrigation design was completed.
1.8The Contractor shall coordinate work under this standard with Backflow Prevention for the backflow assembly at the point of connection, with Domestic Water Piping for the potable supply upstream of the point of connection, and with Earthwork for trench excavation, bedding, and backfill. 2 Referenced Standards
2.1Materials, components, and installation shall comply with the latest adopted edition of the following standards and codes.
| Standard |
Title |
| ASTM D1784 |
Standard Specification for Rigid Poly(Vinyl Chloride) (PVC) Compounds and Chlorinated Poly(Vinyl Chloride) (CPVC) Compounds |
| ASTM D1785 |
Standard Specification for Poly(Vinyl Chloride) (PVC) Plastic Pipe, Schedules 40, 80, and 120 |
| ASTM D2241 |
Standard Specification for Poly(Vinyl Chloride) (PVC) Pressure-Rated Pipe (SDR Series) |
| ASTM D2466 |
Standard Specification for Poly(Vinyl Chloride) (PVC) Plastic Pipe Fittings, Schedule 40 |
| ASTM D2467 |
Standard Specification for Poly(Vinyl Chloride) (PVC) Plastic Pipe Fittings, Schedule 80 |
| ASTM D2464 |
Standard Specification for Threaded Poly(Vinyl Chloride) (PVC) Plastic Pipe Fittings, Schedule 80 |
| ASTM D2564 |
Standard Specification for Solvent Cements for Poly(Vinyl Chloride) (PVC) Plastic Piping Systems |
| ASTM D2855 |
Standard Practice for the Two-Step (Primer and Solvent Cement) Method of Joining PVC or CPVC Pipe and Piping Components with Tapered Sockets |
| ASTM D3139 |
Standard Specification for Joints for Plastic Pressure Pipes Using Flexible Elastomeric Seals |
| ASTM F477 |
Standard Specification for Elastomeric Seals (Gaskets) for Joining Plastic Pipe |
| ASTM D2239 |
Standard Specification for Polyethylene (PE) Plastic Pipe (SIDR-PR) Based on Controlled Inside Diameter |
| ASTM D3035 |
Standard Specification for Polyethylene (PE) Plastic Pipe (DR-PR) Based on Controlled Outside Diameter |
| ASTM D3350 |
Standard Specification for Polyethylene Plastics Pipe and Fittings Materials |
| ASTM D2774 |
Standard Practice for Underground Installation of Thermoplastic Pressure Piping |
| ASSE 1013 |
Performance Requirements for Reduced Pressure Principle Backflow Prevention Assemblies |
| ASSE 1015 |
Performance Requirements for Double Check Backflow Prevention Assemblies |
| ASSE 1020 |
Performance Requirements for Pressure Vacuum Breaker Assemblies |
| NSF/ANSI 61 |
Drinking Water System Components — Health Effects |
| NSF/ANSI/CAN 372 |
Drinking Water System Components — Lead Content |
| ANSI/ASABE S627 |
Weather-Based Landscape Irrigation Control Systems |
| EPA WaterSense |
Specification for Weather-Based Irrigation Controllers; Specification for Soil Moisture-Based Irrigation Controllers; Specification for Spray Sprinkler Bodies |
| ANSI/ASABE S376 |
Design, Installation, and Performance of Underground, Thermoplastic Irrigation Pipelines |
| UL 1951 |
Standard for Electric Plumbing Accessories (irrigation controllers / transformers) |
| NFPA 70 |
National Electrical Code (low-voltage control wiring and controller power) |
2.2Where the contract documents, the Authority Having Jurisdiction (AHJ), the local water purveyor, or a referenced standard impose conflicting requirements, the more stringent requirement shall govern unless the designer of record directs otherwise in writing.
2.3The adopted plumbing code and the local cross-connection control program shall take precedence on any matter of backflow protection.
2.4The local water purveyor's rules and the jurisdiction's cross-connection control program shall be identified by the Contractor during pre-construction.
NOTE Many jurisdictions require a permit for the irrigation meter and backflow assembly, require certified testing of the backflow assembly by a licensed tester before the meter is activated, and enforce watering-day and watering-time restrictions that the controller program must accommodate. (2.5)
2.6Where the project pursues a green building rating (such as LEED or a local water-efficient landscape ordinance), the irrigation system shall meet the water-budget and equipment requirements of that program in addition to this standard.
3 Submittals
3.1 Action Submittals
3.1.1The Contractor shall submit the following for the designer of record's review and acceptance prior to procurement or installation:
- Product data for all pipe and fittings, indicating the manufacturer, the applicable ASTM standard, the pressure class or schedule, the joining method (solvent weld, gasketed, or insert-fitting), and NSF/ANSI 61 and NSF/ANSI/CAN 372 certification where the system is connected to a potable supply
- Product data for the backflow prevention assembly, coordinated with Backflow Prevention, including the ASSE listing, the assembly type, and the approval listing required by the local cross-connection control program
- Product data for all isolation valves, zone control (remote control) valves, the master valve, and quick-coupling valves, indicating body and seat material, pressure rating, flow-control capability, and solenoid voltage
- Product data for all spray heads, rotors, and nozzles, including the manufacturer's precipitation-rate and radius performance tables at the design operating pressure, and identification of matched-precipitation-rate nozzle sets by arc
- Product data for all drip and micro-irrigation components, including emitter flow rate, pressure-compensation range, emitter spacing, the pressure regulator setting, the required filtration mesh or micron rating, and air/vacuum relief and flush devices
- Product data for the controller, indicating WaterSense and ANSI/ASABE S627 listing (for weather-based controllers) or WaterSense soil-moisture listing, the number of stations, the surge and lightning protection, and the communication method (on-board, internet, or central control)
- Product data for the flow sensor, rain sensor, freeze sensor, and any soil-moisture sensors, with the controller-compatibility documentation
- Valve box product data, indicating the box size, load rating, and lid marking
- Low-voltage control wire and splice product data, indicating conductor type, insulation rating for direct burial, and the waterproof splice connector type
- A zone schedule (Contractor's coordination set) listing each zone number, the emission device type, the design flow in gallons per minute (GPM), the design operating pressure, the controller station assignment, and the hydrozone served
- An as-built record-set procedure describing how the Contractor will maintain a daily-updated markup showing actual mainline routing, valve locations, sleeve locations, and wire paths
☐ Pipe and fitting product data (with NSF 61/372 where potable-supplied)
☐ Backflow prevention assembly product data and AHJ approval listing
☐ Valve product data (isolation, zone control, master, quick-coupling)
☐ Spray head, rotor, and nozzle product data with precipitation tables
☐ Drip and micro-irrigation component product data
☐ Controller product data (WaterSense / ANSI-ASABE S627 listing)
☐ Flow sensor, rain sensor, freeze sensor, and soil-moisture sensor data
☐ Valve box product data
☐ Low-voltage control wire and waterproof splice product data
☐ Zone schedule (Contractor coordination set)
☐ As-built record-set procedure
3.1.2Work shall not proceed on any system or zone until the corresponding submittals have been reviewed and returned.
3.2 Closeout Submittals
3.2.1Prior to substantial completion the Contractor shall provide the following:
- As-built irrigation record drawings showing actual mainline and lateral routing dimensioned from permanent reference points, the location and station assignment of every zone valve, the location of the master valve and flow sensor, the location of every sleeve and the size and contents of each, the routing of all control wire, and the location of all isolation valves, quick-coupling valves, and drain valves
- A controller programming record showing the final program for every station: run time, start times, watering days, seasonal adjustment (percent), cycle-and-soak settings, and any sensor-based overrides, as left at turnover
- Field test reports for the mainline pressure test, the lateral coverage test, and the operational test of every zone, signed by the Contractor's superintendent and the witnessing inspector
- The backflow assembly's initial certification test report from a licensed backflow tester, as required by the local cross-connection control program
- Operation and maintenance (O&M) manuals for the controller, the backflow assembly, the master valve and flow sensor, and all specialty devices, including the manufacturer's seasonal start-up and winterization procedures
- A laminated zone map mounted at or adjacent to the controller, identifying each station number and the area it serves
- Manufacturer warranties for all products carrying a warranty
- A spare-parts inventory turned over to the Owner as specified in the Spare Parts section
☐ As-built irrigation record drawings
☐ Controller programming record (as-left program)
☐ Field test reports (mainline pressure, lateral coverage, zone operation)
☐ Backflow assembly initial certification test report
☐ Operation and maintenance (O&M) manuals
☐ Laminated zone map mounted at controller
☐ Manufacturer warranties
☐ Spare-parts inventory turned over to Owner
4 Quality Assurance
4.1 Installer Qualifications
4.1.1Landscape irrigation systems shall be installed by a contractor regularly engaged in the installation of commercial irrigation systems, with verifiable experience on at least three projects of comparable size and complexity within the preceding five years.
4.1.2Where the jurisdiction licenses irrigation contractors or requires a certified irrigation technician, the Contractor shall hold the applicable license or shall employ certified personnel as required by the AHJ.
4.2 Backflow Tester Certification
4.2.1The backflow prevention assembly shall be tested and certified upon installation by a tester certified under the local cross-connection control program.
4.2.2The Contractor shall coordinate this certification with the requirements of Backflow Prevention. 4.2.3The Contractor shall not place the irrigation system in service until the assembly has passed its initial certification test and the test report has been filed with the water purveyor where required.
4.3 Pre-Installation Conference
4.3.1Prior to beginning irrigation installation the Contractor shall participate in a pre-installation conference attended by the Contractor's superintendent, the irrigation designer or landscape architect of record, the general contractor's site superintendent, and the landscape installer.
4.3.2The conference shall review the point-of-connection arrangement and verified static pressure and flow, the hydrozone layout and zone schedule, the sleeve locations and the coordination of sleeving with paving and hardscape operations, the controller location and power source, and the sequence of irrigation work relative to grading, planting, and paving.
4.4 Verification of Available Pressure and Flow
4.4.1Before installing any piping the Contractor shall verify the actual static water pressure and available flow at the point of connection by field measurement, and shall compare the measured values to the design assumptions stated on the irrigation drawings.
NOTE The performance of every spray head, rotor, and drip device depends on the operating pressure delivered to it; an irrigation system designed for a static pressure that the site does not actually provide will under-perform at every zone, and the deficiency is far cheaper to discover before trenching than after. (4.4.2)
4.4.3The Contractor shall report any discrepancy between measured and design pressure or flow to the designer of record before proceeding.
5 Environmental and Service Conditions
5.1 Water Source and Quality
NOTE The water source determines the backflow protection required, the filtration required for drip and micro-irrigation, and, for reclaimed water, the marking and separation requirements imposed by the jurisdiction. (5.1.1)
Potable municipal supply through dedicated irrigation meter
Potable municipal supply, shared with domestic service (separate backflow)
Reclaimed / reuse (purple-pipe) supply
On-site well
Surface water (pond, lake, harvested stormwater)
Per drawings
5.1.2The irrigation water source shall be as indicated on the drawings — potable supply, non-potable reclaimed/reuse supply, well, or surface water.
5.1.3Where the source is reclaimed or reuse water, all piping, valve boxes, and appurtenances shall be identified in accordance with the jurisdiction's reclaimed-water requirements — typically purple (Pantone 522C) pipe or purple identification tape, purple valve box lids embossed with a non-potable warning, and the separation distances from potable lines required by the adopted plumbing code.
5.1.4On a reclaimed system, quick-coupling valves and hose bibs shall use a non-interchangeable coupler keyed differently from potable connections so that a hose cannot be cross-connected.
5.2 Freeze Exposure
5.2.1In climates subject to freezing, the system shall be designed and installed to permit complete winterization by draining or by compressed-air blow-out.
5.2.2Components subject to freeze damage — the backflow assembly, exposed piping, and valves above the frost line — shall be protected, drained, or insulated as indicated.
5.2.3The mainline and laterals shall be installed at a depth and on a grade that permits draining toward manual or automatic drain valves at low points where a drain-down winterization method is used.
5.3 Soil and Slope Conditions
5.3.1The application rate of the emission devices shall not exceed the intake (infiltration) rate of the soil for the slope on which they are installed; otherwise the excess application runs off, wasting water and eroding the landscape.
NOTE On slopes and on tight (clay) soils, the irrigation design addresses runoff with cycle-and-soak scheduling, with low-precipitation-rate nozzles, or with drip irrigation. (5.3.2)
5.3.3The Contractor shall install the emission devices and program the controller to deliver the cycle-and-soak run times indicated on the zone schedule.
5.3.4The Contractor shall report any field condition (such as a steeper finished slope than the design assumed) that would produce runoff.
6 Point of Connection and Backflow Prevention
6.1 Point of Connection
6.1.1The point of connection shall be made as indicated on the drawings, downstream of the irrigation meter (or downstream of the building service tap for a shared supply) and shall include an isolation valve, the backflow prevention assembly, and a means of draining the assembly for winterization where required.
6.1.2The point-of-connection assembly shall be supported independently of the piping so that the weight of the backflow assembly and valves is not carried by the buried mainline.
6.2 Backflow Prevention Assembly
NOTE For landscape irrigation a reduced-pressure-principle assembly is typical because it provides protection against both backsiphonage and backpressure and is accepted for high-hazard applications. (6.2.1)
Reduced-pressure-principle assembly (ASSE 1013) — typical for irrigation high-hazard
Double check valve assembly (ASSE 1015) — where permitted for the hazard level
Pressure vacuum breaker assembly (ASSE 1020) — backsiphonage only, no chemical injection
Per local cross-connection control program and drawings
6.2.2A backflow prevention assembly shall be provided at the point of connection to protect the potable supply from the irrigation system, which the plumbing code classifies as a high-hazard cross-connection because of the potential for fertilizer, pesticide, and soil contaminants to be drawn back through the irrigation piping.
6.2.3The assembly type shall be as required by the local cross-connection control program and as indicated on the drawings.
NOTE The reduced-pressure-principle assembly is the recognized choice where any chemical injection (fertigation), where backpressure from elevated zones, or where high-hazard contaminants are possible. (6.2.4)
6.2.5A pressure vacuum breaker protects only against backsiphonage and shall not be used where chemical injection is present or where the assembly can be subjected to backpressure.
6.2.6The detailed selection, installation height, freeze protection, and certification testing of the assembly are governed by Backflow Prevention and the local program; this standard requires only that an approved assembly of the correct type be provided and integrated into the irrigation system, and that the irrigation system not be energized until the assembly has passed its initial certification. 6.3 Pressure Regulation at the Point of Connection
NOTE Excess pressure mists spray nozzles into fine droplets that drift and evaporate, wastes water, and accelerates wear on every component; pressure regulation at the point of connection (in addition to, or in place of, pressure-regulating heads) is the most reliable way to control it. (6.3.1)
○ Not required — supply pressure within component operating range
○ Master pressure-reducing valve at point of connection
○ Pressure regulation at each zone valve
○ Pressure-regulating spray bodies / rotors only (no master regulator)
○ Per drawings
6.3.2Where the static supply pressure exceeds the maximum operating pressure of the system components, a pressure-reducing valve or a master pressure regulator shall be provided downstream of the backflow assembly to limit the system pressure to the design value.
7 Piping Materials
7.1 Mainline and Lateral Piping Material
NOTE PVC pipe is the predominant material for buried commercial irrigation in most of the United States; polyethylene pipe is used where its flexibility, freeze tolerance, or suitability for trenchless pulling is advantageous, and is common in northern climates and on rocky sites. (7.1.1)
PVC Schedule 40 (ASTM D1785), solvent-welded
PVC Class 200 / SDR-PR (ASTM D2241), solvent-welded
PVC Class 200 / SDR-PR (ASTM D2241), gasketed (3 in. and larger)
Polyethylene (ASTM D2239 or D3035), insert or fusion fittings
Per drawings
PVC Class 200 / SDR-PR (ASTM D2241), solvent-welded
PVC Schedule 40 (ASTM D1785), solvent-welded
Polyethylene (ASTM D2239 or D3035), insert fittings
Per drawings
7.1.2The pipe material for the mainline and laterals shall be as indicated on the drawings.
NOTE The mainline operates under continuous (constant) pressure between the point of connection and the zone valves, and therefore warrants the more conservative material — Schedule 40 PVC or a heavier pressure class — and gasketed joints on larger diameters to accommodate thermal movement. (7.1.3)
NOTE Laterals operate under pressure only while their zone is running, so Class 200 PVC is commonly used for laterals as an economical pressure-rated choice. (7.1.4)
7.1.5The Contractor shall not use Schedule 40 cellular-core (foam-core) PVC, drain-waste-vent (DWV) pipe, or sewer pipe for any pressurized irrigation piping.
7.1.6Only pressure-rated pipe marked with the applicable ASTM pressure designation shall be installed under pressure.
7.2 PVC Pipe
Class 200 (SDR 21) — typical for laterals
Class 315 (SDR 13.5) — high-pressure or small-diameter laterals
Schedule 40 — where indicated for laterals subject to handling stress
Per drawings
7.2.1PVC pipe shall be manufactured from a Class 12454 PVC compound conforming to ASTM D1784, and shall be marked with the manufacturer's name, the nominal size, the applicable ASTM standard (D1785 for schedule-rated or D2241 for SDR pressure-rated pipe), the pressure rating or schedule, and the NSF mark where the system is supplied from a potable source.
7.2.2PVC pipe shall be stored under cover or otherwise shaded prior to installation; prolonged ultraviolet exposure degrades the pipe surface and embrittles PVC over time.
7.3 PVC Fittings and Solvent-Weld Joints
○ Solvent weld with primer and cement (ASTM D2855 two-step)
○ Gasketed bell-and-spigot (ASTM D3139, F477 gaskets) — mainline 3 in. and larger
○ Threaded (Schedule 80 fittings only, ASTM D2464) — at valves and transitions
○ Per drawings
7.3.1Solvent-weld socket fittings for Schedule 40 pipe shall conform to ASTM D2466.
7.3.2Socket fittings for Schedule 80 pipe shall conform to ASTM D2467.
7.3.3Threaded fittings shall conform to ASTM D2464 and shall be Schedule 80 where threaded, because Schedule 40 threaded PVC is prone to splitting at the threads.
7.3.4Slip-fit fittings used with Class 200 pipe shall be pressure-rated socket fittings compatible with the pipe's outside diameter.
7.3.5Solvent cement shall conform to ASTM D2564 and primer to the cement manufacturer's specification.
7.3.6Joints shall be made by the two-step primer-and-cement method in accordance with ASTM D2855.
7.3.7Every solvent-weld joint shall be primed and cemented; the use of cement without primer ("one-step" cement) is not acceptable for buried pressure piping under this standard, because the primer softens and cleans the bonding surfaces and is what produces a reliable solvent weld.
7.3.8The cured joint shall be allowed to set and cure for the time specified by the cement manufacturer for the pipe size and ambient temperature before the line is pressurized.
NOTE Pressurizing or backfilling a green (uncured) solvent weld is a frequent cause of joint failure. (7.3.9)
7.3.10Threaded connections shall be made with PTFE tape or a non-hardening pipe-thread sealant and hand-tightened plus the manufacturer's specified turns; over-tightening threaded PVC splits the female fitting.
7.4 Polyethylene Pipe
NOTE PE is well suited to freeze-prone climates because it expands rather than splitting under residual ice, and to rocky or trenchless conditions because it can be pulled through a bored path. (7.4.1)
○ Barbed insert fittings with stainless steel clamps (two clamps per fitting)
○ Thermal fusion (larger-diameter mainline)
○ Per drawings
7.4.2Polyethylene pipe, where indicated, shall conform to ASTM D2239 (controlled inside diameter) or ASTM D3035 (controlled outside diameter), manufactured from a PE compound conforming to ASTM D3350.
7.4.3PE pipe shall be joined with the manufacturer's barbed insert fittings secured with stainless steel pinch clamps or screw clamps, or by thermal fusion where indicated for larger diameters.
8 Valves and Valve Boxes
8.1 Isolation Valves
8.1.1Isolation (shutoff) valves shall be provided at the point of connection, at the base of each mainline branch serving a group of zones, and at locations that allow portions of the system to be isolated for maintenance without draining the entire mainline.
8.1.2Isolation valves shall be resilient-wedge gate valves, ball valves, or brass gate valves as indicated, rated for the working pressure of the mainline, and installed in a valve box for access.
8.2 Zone Control (Remote Control) Valves
○ 24 VAC solenoid (standard, hard-wired controller)
○ DC latching solenoid (battery / two-wire decoder systems)
○ Per controller type
○ Flow-control stem at each valve (recommended for balancing)
○ No flow control (fixed) — where zones are pressure-regulated elsewhere
○ Per drawings
8.2.1Each irrigation zone shall be controlled by an electrically actuated remote control valve that opens when its controller station energizes the valve solenoid and closes when the station de-energizes.
8.2.2Zone control valves shall be globe- or angle-pattern diaphragm valves with a 24-volt AC solenoid, a manual internal/external bleed for field operation, and a flow-control stem where indicated to throttle the zone flow.
8.2.3Zone control valve body and bonnet shall be glass-filled nylon, PVC, or brass as indicated, rated for the system working pressure.
8.2.4Zone valves should include a manual bleed so that a single zone can be operated in the field for testing and maintenance without the controller.
8.2.5Zone valves should include a flow-control stem so that flow to each zone can be throttled to balance the system.
8.2.6Only one type of emission device shall be served by a single zone valve — spray heads, rotors, and drip devices shall never be mixed on one zone, because they apply water at radically different precipitation rates and cannot be scheduled together without grossly over- or under-watering one of them.
NOTE Single-emission-device zoning is the single most important zoning principle in irrigation and is addressed further in the Hydrozoning principles applied throughout this standard. (8.2.7)
8.3 Quick-Coupling Valves
8.3.1Quick-coupling valves shall be provided where indicated to allow hose connection for hand-watering, syringing, and washdown without an exposed hose bib.
8.3.2Quick-coupling valves shall be brass, connected to the mainline, and installed in a valve box.
8.3.3On reclaimed-water systems the coupler shall be of a non-interchangeable key type so that it cannot accept a potable hose connector.
8.4 Valve Boxes
Standard duty — turf and planting bed areas (pedestrian only)
Heavy duty / traffic-rated — driveways, parking, and vehicular areas
Per drawings
8.4.1All zone valves, isolation valves, master valves, flow sensors, quick-coupling valves, wire splices, and drain valves shall be installed in valve boxes for access.
8.4.2Valve boxes shall be high-density polyethylene or structural-foam polypropylene with a locking or bolt-down lid, sized so that the valve and its wiring can be serviced without excavation, and load-rated for the location.
8.4.3Valve boxes shall be set flush with finished grade (or 1 inch above finished grade in turf areas where mowing equipment passes, as indicated), on a base of gravel or crushed stone that provides drainage and prevents the valve box from settling and trapping water around the valve and splices.
8.4.4Valve box lids shall be marked or color-coded to identify the contents — control valve, master valve, isolation, or, on reclaimed systems, the non-potable warning.
NOTE Boxes set below grade fill with water and silt, corrode wire splices, and make valves impossible to service. (8.4.5)
9 Sprinkler Heads, Rotors, and Nozzles
9.1 Spray Heads
4 in. — turf areas
6 in. — taller turf and groundcover
12 in. — shrub and tall groundcover beds
Shrub adapter on riser — shrub beds
Per drawings
○ Pressure-regulating spray bodies (WaterSense-labeled, integral regulator)
○ Standard spray bodies (pressure regulated at zone valve or point of connection)
○ Per drawings
9.1.1Spray heads (fixed spray, or spray bodies fitted with fixed or adjustable nozzles) shall be pop-up bodies with the pop-up height indicated for the area served.
9.1.2Spray heads shall be fitted with the matched-precipitation-rate nozzles indicated on the drawings so that all heads within a zone apply water at the same depth per unit time regardless of arc.
9.1.3Spray bodies should be pressure-regulating (with an integral pressure regulator) and should incorporate a check valve where heads at low points would otherwise drain the lateral between cycles.
NOTE A 4-inch pop-up is standard for turf because it clears typical mowed turf height while retracting flush when not operating. Pressure-regulating spray bodies that hold the nozzle at its design pressure (commonly 30 psi for fixed sprays, 40 psi for many rotary nozzles) are the most effective single measure for spray-zone efficiency, because they eliminate the misting and fogging that occurs when an unregulated body is fed at a higher pressure than the nozzle is designed for. WaterSense labels spray sprinkler bodies that incorporate integral pressure regulation. (9.1.4)
9.2 Rotors (Gear-Driven Rotary Heads)
9.2.1Rotors apply water at a lower precipitation rate than spray heads, which makes them better suited to slopes and tight soils but means they must never be combined on the same zone as spray heads.
○ Matched-precipitation nozzle set sized by arc (quarter, half, full)
○ Separate zones by arc (quarter heads, half heads, full heads on distinct zones)
○ Per drawings
9.2.2Rotors (gear-driven rotary sprinklers) shall be used for larger turf areas where their longer throw and lower precipitation rate suit the area and the soil intake rate.
9.2.3Rotors shall be fitted with the nozzle set indicated on the drawings, selected so that the precipitation rate is matched across the arcs within the zone.
NOTE Because a full-circle rotor covers four times the area of a quarter-circle rotor, applying the same flow to both produces four times the precipitation rate on the quarter — the corner gets soaked while the open area stays dry. The design corrects this either by installing a proportionally larger nozzle in the wider-arc heads (so a full-circle head receives roughly four times the flow of a quarter-circle head) or by separating the arcs onto different zones. (9.2.4)
9.2.5The Contractor shall install the specific nozzle assigned to each head on the drawings and shall not field-substitute nozzles, because the substitution destroys the matched precipitation the designer established.
9.3 Matched Precipitation Rate
9.3.1Within any single zone, all emission devices shall apply water at a matched precipitation rate so that a single run time waters the entire zone uniformly.
NOTE Matched precipitation is achieved by selecting nozzles whose flow is proportional to the arc each head covers. (9.3.2)
NOTE A zone that mixes mismatched precipitation rates cannot be scheduled correctly: any run time that adequately waters the low-rate heads over-waters the high-rate heads, producing simultaneous dry spots and runoff. Matched precipitation is the reason emission devices, arcs, and nozzles are specified by the designer rather than chosen in the field. (9.3.3)
9.4 Head-to-Head Coverage
NOTE This overlap is required because the application depth from a single sprinkler is heaviest near the head and tapers to nearly nothing at the edge of its throw; without overlap, the areas between heads receive far less water than the areas near them, producing the characteristic ring or doughnut dry pattern. (9.4.1)
○ Head-to-head (100 percent of radius) spacing per design layout
○ Reduced spacing in high-wind areas (per design, less than full radius)
○ Per drawings
9.4.2Spray heads and rotors shall be installed at the spacing indicated on the drawings to achieve head-to-head coverage — each head's throw reaches the adjacent heads, so that every point in the zone receives water from at least two heads.
9.4.3The Contractor shall install heads at the design spacing and shall not increase spacing to economize on heads, because head spacing greater than the head-to-head design destroys distribution uniformity.
9.4.4Where field conditions (hardscape edges, planting changes, obstructions) prevent the design spacing, the Contractor shall report the condition to the designer rather than leaving a coverage gap.
9.5 Swing Joints and Risers
9.5.1Every spray head and rotor connected to a lateral shall be installed on a flexible swing joint (a triple-swing assembly of marlex/PVC street ells, or a flexible PVC riser) between the lateral fitting and the head.
NOTE The swing joint allows the head to be set precisely to finished grade and to the correct vertical position, and absorbs the impact of foot traffic, mowers, and vehicles without transmitting the load to the buried lateral fitting. (9.5.2)
NOTE Heads installed on a rigid nipple directly into a lateral tee crack the fitting the first time the head is kicked or driven over; the swing joint is not optional on quality commercial work. (9.5.3)
10 Drip and Micro-Irrigation
10.1 Application
10.1.1Drip and micro-irrigation shall be used for planting beds, shrub masses, groundcover, individual trees, and other non-turf areas as indicated, and for turf only where subsurface drip is specifically designed for the area.
NOTE Drip irrigation applies water slowly and directly to the root zone, achieving very high application efficiency and eliminating the wind drift and evaporation losses of spray irrigation; it is the preferred method for beds and is frequently required by water-efficient landscape ordinances for all non-turf plantings. (10.1.2)
10.2 Drip Zone Control Assembly
NOTE The filter protects the small emitter passages from clogging and the pressure regulator holds the drip line at the low pressure (commonly 15 to 40 psi) at which the emitters are rated; both are essential, and a drip zone fed at an unregulated, unfiltered pressure will clog and blow apart. (10.2.1)
150 mesh (approximately 100 micron) — typical for emitter tubing
200 mesh (approximately 75 micron) — fine emitters or marginal water quality
Disc or screen filter sized to zone — per drip product requirement
Per drawings
30 psi regulator — typical for inline-emitter dripline
25 psi regulator — point-source emitters and micro-spray
40 psi regulator — high-flow / high-elevation dripline
Per drip product requirement
10.2.2Each drip zone shall be served by a zone control assembly consisting of, in order, the remote control valve, a line-size filter, and a pressure regulator, sized for the zone flow and set to the design operating pressure of the drip product.
10.3 Emitters and Dripline
NOTE Emitter flow rate and spacing are selected for the plant water demand and the soil's lateral wetting characteristics. (10.3.1)
0.6 GPH per emitter — typical for clay and loam soils
0.9 GPH per emitter — typical for loam
1.0 GPH per emitter — sandy soils and higher demand
Per drawings
12 in. emitter spacing — typical for beds
18 in. emitter spacing — wider plant spacing / sandy soil
9 in. emitter spacing — tight spacing / clay soil
Per drawings
10.3.2Drip devices shall be pressure-compensating so that every emitter delivers the same flow regardless of its position along the line or its elevation, which is what allows long runs and sloped beds to water uniformly.
10.3.3Inline-emitter dripline (tubing with emitters factory-installed at a fixed spacing) shall be used for bed and groundcover coverage.
10.3.4Point-source emitters on distribution tubing shall be used at individual trees and specimen plants as indicated.
10.3.5Emitter flow rate and spacing shall be as indicated on the drawings, selected for the plant water demand and the soil's lateral wetting characteristics.
10.4 Air/Vacuum Relief and Flushing
NOTE The air/vacuum relief valve admits air when the zone shuts down so that the emptying line does not develop a vacuum and draw soil and debris back into the emitters; the flush point allows accumulated sediment to be flushed from the line. (10.4.1)
NOTE Without these, dripline progressively clogs from the ends inward and from soil ingestion at shutdown. (10.4.2)
☐ Air/vacuum relief valve at zone high point
☐ Flush valve or flush cap at end of each dripline run
☐ Manifolded flush header (large bed systems)
10.4.3Each drip zone shall include an air/vacuum relief valve at the high point of the zone and a flush point (flush valve or flush cap) at the end of each dripline run or at a manifolded flush header.
10.5 Subsurface Drip
4 in. — turf and shallow-rooted groundcover
6 in. — shrub beds
Per drawings
10.5.1Where subsurface drip irrigation is indicated — for turf, for medians, or where surface drip would be a trip or vandalism concern — the dripline shall be buried at the depth indicated and shall use dripline with integral check valves (to hold water in the line and prevent backflow of soil at shutdown) and with root-intrusion protection (chemical-impregnated or copper-shielded emitters) to prevent roots from growing into and blocking the emitters.
10.5.2Subsurface drip shall include the same air/vacuum relief and flush provisions as surface drip.
10.5.3The subsurface drip zone shall be mapped on the as-builts because the lines are not visible after installation.
11 Controllers, Sensors, and Control Wiring
11.1 Controller
Weather/ET-based smart controller (WaterSense, ANSI/ASABE S627)
Soil-moisture-based smart controller (WaterSense)
Central-control / cloud-managed controller (multi-site)
Per drawings
448
4681216243248
Default: 12 stations
11.1.1The system shall be operated by an automatic controller with the number of stations indicated, plus spare stations for future expansion.
11.1.2The controller shall be a smart controller that adjusts watering based on local conditions: a weather-based (evapotranspiration, or ET) controller listed under EPA WaterSense and ANSI/ASABE S627, or a soil-moisture-based controller listed under the WaterSense soil-moisture specification.
11.1.3Conventional time-clock controllers that water on a fixed schedule regardless of weather shall not be specified for new commercial systems where a WaterSense-labeled controller is available for the station count, because they waste water by irrigating during and after rain.
NOTE A weather-based controller is the default because it adjusts each zone's run time to the measured or forecast ET demand and is the most widely available smart-controller type for commercial station counts. Soil-moisture-based control is selected where direct measurement of root-zone moisture is preferred, such as on athletic fields or where the landscape palette has well-defined moisture targets. (11.1.4)
11.1.5The station count shall include not fewer than two spare stations beyond the installed zones to accommodate future landscape expansion without replacing the controller.
11.2 Controller Location and Power
○ Exterior wall / pedestal in NEMA-rated outdoor enclosure
○ Interior wall mount (mechanical/electrical room or similar)
○ Per drawings
11.2.1The controller shall be installed at the location indicated, in an enclosure suited to its environment — a NEMA-rated outdoor enclosure for exterior mounting, or an interior wall mount as indicated.
11.2.2Line-voltage power to the controller shall be provided on a dedicated circuit in accordance with NFPA 70, with the controller's low-voltage transformer (listed to UL 1951) stepping the supply down to the 24-volt AC control voltage.
11.2.3Surge and lightning protection shall be provided on the power supply and on the field-wiring common and station outputs, because the long buried control runs of an irrigation system act as antennas for lightning-induced surges that destroy unprotected controller outputs.
11.3 Master Valve
NOTE The master valve protects the site against the continuous risk of a mainline leak or a stuck-open zone valve dumping water for hours or days while the system is unattended; combined with the flow sensor it is the basis of automatic leak detection. (11.3.1)
○ Normally-closed master valve (recommended — mainline pressurized only on demand)
○ Normally-open / no master valve (mainline continuously pressurized)
○ Per drawings
11.3.2A normally-closed master valve shall be installed on the mainline immediately downstream of the backflow assembly (or as indicated) and wired to the controller so that the mainline downstream of the master valve is pressurized only when a zone is calling for water.
11.4 Flow Sensor
NOTE The flow sensor lets the controller learn the expected flow of each zone and detect abnormal flow — a broken lateral or a sheared head shows up as flow higher than the zone's expected value, and a clogged zone or a stuck-closed valve shows up as flow lower than expected. (11.4.1)
NOTE On detecting an abnormal flow, the controller can shut the master valve and alarm, limiting the loss to a single cycle rather than days of leakage. (11.4.2)
○ Flow sensor with controller high-flow shutdown (recommended)
○ Flow sensor for monitoring only (no automatic shutdown)
○ No flow sensor
○ Per drawings
11.4.3A flow sensor shall be installed on the mainline downstream of the master valve and wired to the controller where the controller supports flow monitoring.
11.5 Rain and Freeze Sensors
☐ Rain sensor / rain shutoff device (commonly code-required)
☐ Freeze / low-temperature sensor (freeze-prone climates)
☐ Wind sensor (high-wind or coastal sites)
☐ On-site weather station (large or campus sites)
11.5.1A rain sensor (rain shutoff device) shall be provided and wired to the controller to suspend irrigation during and immediately after measurable rainfall; many jurisdictions require a functioning rain sensor on every automatic irrigation system by code.
11.5.2In freeze-prone climates a freeze (temperature) sensor shall also be provided to suspend irrigation when the temperature approaches freezing, both to avoid wasting water and to prevent the hazard of ice on walks and pavement.
11.5.3The rain sensor's function shall be verified at commissioning by triggering the device and confirming that the controller suspends irrigation.
NOTE A rain sensor that is installed but not wired through the controller's sensor circuit, or that is mounted where roof overhang or tree canopy shields it from rain, provides no benefit. (11.5.4)
11.5.5The Contractor shall mount sensors in open exposure and shall demonstrate the shutoff function at turnover.
11.6 Low-Voltage Control Wiring
One spare conductor to every valve box
Two spare conductors to every valve box (larger systems)
Per drawings
11.6.1Control wiring between the controller and the zone valves, master valve, and sensors shall be direct-burial-rated irrigation control cable (solid-copper, UF-rated or AWG irrigation wire) sized for the run length so that the voltage delivered to the solenoid at the most distant valve remains within the solenoid's operating range.
11.6.2A separate, distinctly colored common (ground) conductor shall serve all valves.
11.6.3At least one spare conductor shall be run with every wire bundle to every valve location for future use and for troubleshooting.
11.6.4Control wire shall be installed in the mainline trench below the mainline where practical, bundled and taped at intervals, with an expansion loop at each valve and at each change of direction.
11.6.5All wire connections and splices shall be made inside a valve box using waterproof, gel-filled or epoxy-filled splice connectors listed for direct burial.
11.6.6Twisted-and-taped splices, wire nuts, and any splice made outside a valve box are not acceptable; a buried connection that is not waterproof corrodes within a season and is the most common cause of dead zones in an irrigation system.
11.6.7No splice shall be buried outside a valve box.
12 Sleeving and Trenching
12.1 Sleeves Under Paving and Hardscape
NOTE The sleeve allows the pipe or wire to be installed, repaired, or replaced without cutting the pavement, and protects the pipe from the load and the saw-cutting that pavement work involves. (12.1.1)
○ Schedule 40 PVC sleeve, minimum twice the pipe/bundle diameter
○ Schedule 80 PVC sleeve under heavy vehicular paving
○ Per drawings
12.1.2Pipe and control wire crossing under paving, sidewalks, curbs, or other hardscape shall be installed in sleeves placed before the paving is constructed.
12.1.3Sleeves shall be Schedule 40 PVC (or other approved conduit) sized at not less than twice the diameter of the pipe or bundle they carry, extend not less than 12 inches beyond the edge of paving on each side, and be marked at each end so they can be located after paving.
12.1.4Pipe sleeves and wire sleeves shall be separate; control wire shall not share a sleeve with a pressure pipe, so that a pipe repair does not require disturbing the wire and vice versa.
12.1.5The Contractor shall coordinate sleeve installation with the paving and hardscape schedule under Earthwork and the paving scopes; a missed sleeve discovered after paving requires either boring under the finished pavement or saw-cutting and patching it, both of which are far more expensive than placing the sleeve in advance. 12.2 Boring and Trenchless Crossings
12.2.1Where a crossing is required under existing paving, under a tree protection zone, or where open trenching is not permitted, the crossing shall be made by boring (horizontal directional drilling or auger boring) and the pipe or sleeve pulled or pushed through the bored path.
12.2.2Bored crossings shall maintain the minimum cover and clearance from other utilities indicated, and the entry and exit pits shall be located outside the protected feature.
12.3 Trenching and Cover
Mainline (constant pressure): 18 in. minimum
Laterals: 12 in. minimum
Drip dripline (surface-buried under mulch): 2 to 4 in.
Deeper cover in agricultural / deep-tillage or freeze-prone areas per drawings
Per drawings
12.3.3Pipe shall be installed on a firm trench bottom free of rock and debris, and bedded and backfilled with material free of rock larger than the manufacturer's limit so that point loads do not damage the pipe.
12.3.4Minimum cover shall be as indicated on the drawings and not less than the values above for the pipe function.
NOTE The deeper cover on the mainline reflects that it is pressurized continuously and is more critical to protect from surface loads and aeration/cultivation equipment than the laterals, which are pressurized only during their cycle. (12.3.5)
12.3.6In freeze-prone regions the cover and the winterization method shall be coordinated so that the system can be reliably drained or blown out; deeper burial alone does not substitute for winterization where ground frost reaches the pipe.
13 Testing
13.1 Mainline Pressure Test
○ Hydrostatic test at 1.5x working pressure, held per spec (typical)
○ Hydrostatic test at fixed pressure per local purveyor requirement
○ Per drawings
13.1.1The mainline (the constant-pressure piping from the point of connection to the zone valves) shall be hydrostatically pressure-tested after the joints have cured and before the trench is backfilled above the pipe, with the zone valves closed or capped.
13.1.2The line shall be filled with water, purged of air, and pressurized to the test pressure indicated — typically 1.5 times the system working pressure, and not exceeding the rating of the lowest-rated component on the line — and held for the duration indicated.
13.1.3Any pressure drop beyond that attributable to thermal change and a small amount of pipe relaxation indicates a leak, which shall be located and repaired before backfill.
13.1.4Compressed air or any gas shall never be used to test solvent-welded irrigation piping.
13.1.5A solvent-welded thermoplastic line under air pressure stores a large amount of energy and can fail explosively, propelling pipe fragments and fittings; all pressure testing of solvent-welded pipe shall be done with water.
13.1.6This prohibition on air testing is absolute and applies regardless of pipe size or test pressure.
13.2 Lateral Flushing
13.2.1Before the heads, emitters, or drip devices are installed, every lateral shall be flushed by running water through the open lateral ends to carry out the dirt, solvent-cement shavings, and debris that accumulate during assembly.
13.2.2Flushing shall continue until the discharge runs clean.
NOTE Debris left in the laterals lodges in head nozzles and emitter passages and is a leading cause of clogged and erratic emission devices at start-up; flushing before installing the emission devices is far more effective than trying to clear debris through the installed nozzles. (13.2.3)
13.3 Coverage and Operational Test
Visual operational test of every zone (typical)
Visual test plus catch-can distribution uniformity audit on turf zones
Per drawings / water-efficiency program requirement
13.3.1After all heads, emitters, and devices are installed and the controller is programmed, each zone shall be operated and observed for full operational performance: every head and emitter shall operate, heads shall pop up and rotate (rotors) through their assigned arcs, spray patterns shall be adjusted to keep water on the landscape and off pavement and buildings, and coverage shall be verified to be uniform with no dry gaps and no excessive overspray or runoff.
13.3.2Coverage of turf zones may be verified by observation and, where required, by a catch-can distribution-uniformity test in accordance with recognized audit procedures.
13.3.3The Contractor shall adjust each head's arc and radius and each nozzle's pattern during this test so that water is applied to the intended landscape and not to walks, walls, windows, or pavement.
NOTE Overspray onto hardscape is wasted water and a slip and staining hazard, and is a frequent cause of post-occupancy complaints. (13.3.4)
13.3.5Any head or emitter that does not operate correctly, any coverage gap, and any overspray shall be corrected and the zone re-tested.
13.4 Backflow Assembly Test
13.4.1The backflow prevention assembly shall be tested and certified by a certified tester as required by the local cross-connection control program before the system is placed in service, coordinated with Backflow Prevention. 13.4.2The certification test report shall be included in the closeout submittals and filed with the water purveyor where required.
14 Commissioning and Controller Programming
14.1 Controller Programming
☐ Station-by-station run times, start times, and watering days recorded
☐ Seasonal adjustment / ET source configured and documented
☐ Cycle-and-soak settings for slope and tight-soil zones
☐ Rain, freeze, and flow-sensor responses configured and tested
☐ Laminated zone map posted at controller
14.1.1After all testing is complete, the Contractor shall program the controller for the as-installed system and shall set up the smart-controller features for the site.
14.1.2Programming shall include, for each station: the assigned zone and its emission-device type, the run time and number of start times computed for the plant demand and the soil intake rate (using cycle-and-soak where the intake rate is exceeded), the allowed watering days and times consistent with any local watering restrictions, the seasonal-adjustment or ET-source configuration, and the rain, freeze, and flow-sensor responses.
14.1.3The as-left program shall be recorded in the closeout submittals and posted at the controller.
14.2 Owner Instruction
14.2.1The Contractor shall instruct the Owner's personnel in the operation of the controller, including manual operation of zones, adjustment of run times and seasonal adjustment, response to sensor alarms, and the seasonal start-up and winterization procedures.
14.2.2The instruction shall be documented and shall be supported by the O&M manuals provided in the closeout submittals.
15 Winterization
15.1 Winterization Method
NOTE Excessive air pressure ruptures fittings and over-speeds rotor gears. (15.1.1)
Compressed-air blow-out (zone-by-zone, pressure limited per material)
Gravity drain to manual/automatic drain valves at low points
Combination drain plus blow-out
Not required — non-freezing climate
Per drawings
15.1.2In freeze-prone climates the system shall be winterized at the end of each watering season by isolating the supply, draining the backflow assembly and exposed components, and clearing water from the buried piping either by gravity drainage to drain valves at low points or by compressed-air blow-out.
15.1.3Where the winterization method is compressed-air blow-out, the air supply shall be regulated so that the blow-out pressure does not exceed the lowest-rated component on the zone being cleared, and in no case exceeds 80 psi for PVC piping or 50 psi for polyethylene piping.
15.1.4The blow-out air shall be introduced through a dedicated blow-out connection downstream of the backflow assembly, never through the backflow assembly itself.
15.1.5The blow-out shall be performed zone by zone, energizing one zone at a time so that the air clears the line at a controlled velocity; blowing all zones at once over-pressurizes the mainline and starves each lateral of the airflow needed to clear it.
15.1.6The first seasonal start-up after winterization shall re-pressurize the system slowly with the zone valves open to purge air, and shall be followed by an operational check of every zone.
15.1.7The Contractor's first-season winterization (where it falls within the warranty period) and the start-up the following spring shall be included in the work or in the O&M instruction as indicated.
16 Warranty
16.1 Warranty Coverage
1 year from substantial completion
2 years from substantial completion
Per contract documents
16.1.1The Contractor shall warrant the irrigation system, including all piping, valves, heads, emitters, drip components, controller, sensors, wiring, and the workmanship of installation, against defects in materials and workmanship for the project warranty period beginning at substantial completion.
16.1.2Warranty obligations include correction of leaks, failed valves and solenoids, clogged or failed emission devices not attributable to Owner neglect, settlement at trenches that exposes or damages piping, and controller or sensor failures.
16.1.3Manufacturer warranties for the controller, valves, heads, and specialty devices, where they extend beyond the Contractor's installation warranty, shall be passed through and assigned to the Owner at closeout.
16.1.4The warranty does not relieve the Contractor of liability for latent defects discovered after the warranty period — including pipe installed at insufficient cover, splices made outside valve boxes, mixed emission devices on a single zone, or substituted nozzles that defeat matched precipitation — which remain the Contractor's responsibility whenever discovered.
17 Spare Parts
17.1 Spare-Parts Inventory
☐ Spare nozzles — representative quantity of each type installed
☐ Spare spray bodies and rotor internal assemblies
☐ Spare drip emitters and fittings
☐ Quick-coupler key(s) and controller key(s)
☐ Special service tools for installed heads and valves
☐ Spare waterproof wire-splice connectors
17.1.1The Contractor shall turn over to the Owner at closeout a spare-parts inventory to support routine maintenance without immediate reordering.
17.1.2The inventory shall include a representative quantity of each type of nozzle installed, spare drip emitters and fittings, the special tools required to service the heads and valves installed (including the quick-coupler key and the controller key), and spare waterproof wire-splice connectors.