LayoutWise

Sprinkler Layout Planner

Enter the lawn size and how much water your supply delivers. You get a head-to-head layout, the nozzles for each head, how to split it into zones, how long to run them and a parts list.

Your lawn

1. Lawn
Length
ft
in
Width
ft
in
2. Heads
3. Water supply

Heads

15

5 x 3, head to head

Zones

4

up to 10 gpm each

Total flow

29.6 gpm

all heads

Run time

32 min

per zone for 1" a week

Head layout

12.5 ft x 15 ft spacing
Zone 1: 5 headsZone 2: 2 headsZone 3: 2 headsZone 4: 6 heads

Every head throws water all the way to its neighbors (head-to-head coverage) — the only way to water evenly. Corners get quarter circles, edges half circles.

Shopping list

  • ✓Spray heads (4" pop-up, pressure-regulated 30 psi): 15
  • ✓Nozzles, 15-ft matched precipitation: 3 full, 8 half, 4 quarter
  • ✓Zone valves: 4 (with a valve box)
  • ✓Controller with at least 4 stations
  • ✓Pipe: about 199 ft of 3/4" or 1" PVC or poly for the laterals, plus the main line from your water supply
  • ✓Swing pipe and fittings: 15 x 12"–18" pieces with two elbows each
  • ✓Backflow preventer (required by code; your local water utility sets the type)

Spray flows are Rain Bird MPR nozzles at 30 psi. Check your static water pressure with a gauge before you buy — most heads need 30–50 psi. Call 811 before digging.

Head-to-head coverage

Sprinklers throw most of their water close to the head and very little at the edge of their reach. To water evenly, each head must spray all the way to the next head. That means spacing heads no farther apart than their radius — 15 ft apart for 15-ft nozzles. Spacing them wider leaves dry rings between heads that no amount of extra watering fixes.

Spray heads or rotors?

Spray heads cover up to about 15 ft and put down water fast, so they suit small lawns, narrow strips and odd shapes. Rotors turn slowly and throw 25–45 ft, so a large lawn needs far fewer of them and less pipe. Never mix sprays and rotors in the same zone: rotors apply water three or four times slower, so one part of the zone would flood while the other stays dry.

Matched precipitation

A quarter-circle nozzle covers a quarter of the area of a full circle, so it should use a quarter of the water. Matched-precipitation nozzles are made that way: a 15-ft spray uses about 3.7 gpm for a full circle, 1.85 for a half and 0.92 for a quarter at 30 psi. With matched nozzles, corners, edges and the middle all get the same amount.

Measure your water supply

Time how long the outdoor faucet nearest the meter takes to fill a 5-gallon bucket. Divide 5 by the seconds and multiply by 60 to get gallons per minute. Also check the static pressure with a hose-thread gauge: most sprinkler heads work best at 30–50 psi. The planner fills each zone with heads until it reaches your available flow.

How long to run each zone

Most lawns need about an inch of water a week, including rain. Spray heads apply roughly 1.5 inches an hour, so about 40 minutes a week per zone, usually split into two or three waterings. Rotors apply closer to half an inch an hour and need about two hours a week. Water early in the morning to cut evaporation and disease.

Before you dig

Call 811 a few days ahead so buried utility lines get marked. Most areas require a backflow preventer between the sprinkler system and your drinking water; your water utility or building department tells you which type, and some require a licensed installer for that part.

Sources: Rain Bird MPR nozzle performance data. Starting a new lawn? Use the sod and grass seed calculator.