Irrigation System Reference

Why this matters

Lawn + landscape watering systems require knowledge across plumbing + electrical + horticulture. Wrong design = dry spots OR wasted water + overspray. The tech who can design, troubleshoot, + service irrigation delivers customer satisfaction + recurring revenue. This is the field card.

Irrigation types

Spray heads: pop-up sprayers; full / half / quarter pattern; fixed arc.

Rotary heads: pop-up rotors; rotating water stream; adjustable arc + radius.

Bubblers: tree wells + planters; saturate base of plant.

Drip irrigation: low-flow emitters; precise placement; gardens + shrubs.

Micro-spray: short-radius spray; gardens + landscape.

Subsurface drip: buried; lawns; water-conservation focus.

Drip line / soaker hose: emitter line on surface OR buried.

Coverage by head type

Spray head:

• Pop-up height: 4" - 12" (taller for tall grass / mulch)
• Throw: 5 - 15 ft
• Pattern: 0° - 360°
• Flow: 1 - 4 GPM each

Rotary head:

• Pop-up height: 4" - 12"
• Throw: 25 - 65 ft
• Pattern: adjustable 40° - 360°
• Flow: 1.5 - 8 GPM each

Pressure-regulated heads (PRS40 series): consistent flow regardless of system pressure variation; longer life + uniform coverage.

Sprinkler manufacturers

Hunter: most-common residential; PGP rotor, Pro-Spray spray head, PGV valve.

Rain Bird: similar product range; 5000 series rotors.

Toro: Sprinkler T7 spray, T-rotor.

K-Rain: rotor + valve options.

Irritrol: valves + commercial.

Spacing rule (head-to-head coverage)

Head-to-head: each head must cover the next head's location.

Triangular spacing: best uniformity.

Square spacing: easier layout.

Spacing: typical 1 ft less than throw distance. 15 ft throw → 14 ft spacing.

Result: uniform precipitation; no dry spots.

Pipe + valve sizing

Mainline: 1" - 1.5" PVC for residential supply.

Lateral lines: 3/4" - 1" PVC for branch.

Schedule 40 PVC: most common.

Schedule 80 PVC: higher pressure; commercial.

Poly tubing (drip): 1/2" - 3/4" for drip systems.

Valves: 1" zone valves typical; 24V solenoid; Hunter PGV / Rain Bird DV.

Zone design

Group similar-flow heads: rotors with rotors, spray with spray.

Each zone: 4 - 12 GPM typical; depends on supply.

Zones: separated by valve; controlled by timer.

Common zoning:

• Front lawn (full sun, high water)
• Back lawn
• Shrub beds (lower water)
• Drip zones (low water)
• Drip mulched / vegetable garden

Backflow prevention (REQUIRED)

PVB (pressure vacuum breaker): residential; basic protection.

RPZ (reduced pressure zone): highest protection; commercial + irrigation main.

DCV (double-check valve): medium protection.

Per IPC + most local codes: irrigation has higher cross-contamination risk than house plumbing.

Annual testing: certified tester; commercial + some residential.

Controllers + timers

Hard-wired (in box): traditional timer; 4 - 24 zones common residential.

Wi-Fi smart controller: Rachio, Rain Bird ST8, Hunter Hydrawise; remote control + weather data.

Battery-powered: standalone; for areas without power.

Wireless rain sensor: cuts system on rain; required by some codes.

Moisture sensor: ground-mounted; more accurate than rain sensor.

Common features: multiple programs, run times by zone, soak-and-cycle, seasonal adjust.

Valves + manifolds

Solenoid valve: 24V activates valve via control wire.

Anti-siphon valve: integrated backflow + valve; older design.

Manifold (valve box): 1 - 6 valves grouped; in below-ground box with cover.

Common boxes: 6 × 12 (1 valve), 12 × 18 (multi-valve), full-zone enclosures.

Common irrigation problems

Brown / dry spots: uneven coverage; head broken / blocked; pressure low.

Wet spots / pooling: head leaking; supply line leak; head buried; pressure too high.

No water at zone: blown valve solenoid; bad wiring; controller fail; mainline issue.

Constant running / not shutting off: stuck valve diaphragm; debris.

Head pop-up not retracting: dirty / spring weak; debris in canister.

Whistling / pressure: head restriction; over-pressure; install PRS.

Freezing / cracked PVC: insufficient winterization.

Winterization

Required in freezing climates.

Blow out lines with compressor: high CFM (100+); low pressure (50 PSI max for PVC).

Drain valves drain mainline: where applicable.

Anti-siphon valves: remove + drain OR insulated cover.

Backflow preventer: drain + insulate; some require removal.

Spring start-up

Check + replace: damaged sprinklers, broken pipes.

Adjust spray patterns: months of weather may have shifted.

Calibrate flow + pressure: especially after winter.

Test backflow preventer: per code.

Reset controller programs: seasonal + weather changes.

Drip system specifics

1/2" mainline (poly): from valve to area.

1/4" emitter line: from mainline to plant.

Emitters: 0.5, 1, 2, 4 GPH common; pressure-compensating preferred.

Pressure regulator: drip needs 25 - 30 PSI vs 30+ PSI spray.

Filter: required to prevent emitter clogging; 150-mesh typical.

Flush flush at end of run: open-end periodically to clear sediment.

Smart controller features

Weather-based adjustment: skips watering after rain; adjusts based on forecast.

Soak + cycle: shorter runs with rest periods; reduces runoff.

Plant-specific zone settings: lawn vs garden vs xeriscape.

Reporting: water usage + consumption.

Common irrigation mistakes

Wrong spray pattern (overspray onto driveway = wasted water + fines). Skipping backflow preventer (code violation; contamination risk). Undersized supply (low pressure; bad coverage). Mixing head types in zone (rotor + spray same zone = uneven coverage). Forgotten winterization (cracked pipes). Skipping drip filter (emitters clog).

Customer education

Watering frequency + duration: based on grass type + climate + season. Generally less frequent + longer better (encourages deep roots).

Best time to water: early morning (5 - 9 am); reduces evaporation + fungal issues.

Don't run during storm: smart controllers handle automatically.

Annual checkup: pre-summer + winterization.

Truck stock

PVC fittings (3/4" + 1"; tees, elbows, couplings, glue), valve box, 24V solenoid valve, PVB backflow, common sprinkler heads (Hunter Pro Spray + PGP rotor, Rain Bird), spare nozzles, controller battery, 6V battery, irrigation glue + primer, replacement diaphragm, valve key, irrigation flag markers.

Tools

Voltmeter (test solenoid + wiring), valve locator (radio), trenching tool / vibratory plow (for lines), 1.5" PVC saw + heavy cement, irrigation key (tool for adjusting heads), goof plug (PVC line cap).

References

• IPC + UPC irrigation requirements
• IBMA (Irrigation Association)
• WaterSense + EPA WaterSense Irrigation Pro standards
• Manufacturer technical data (Hunter, Rain Bird, Toro, K-Rain)
• Manuall internal: Pipe Sizing Materials, Common Valves Types