How long should each sprinkler zone run?
Each zone's run time depends on how fast it applies water (its precipitation rate) and how much water you're aiming to apply. Because spray heads, rotors and drip zones all apply water at different rates, and a system commonly mixes them across zones, a single "run 20 minutes" setting for the whole controller rarely fits every zone correctly.
This calculator builds a full program: enter a target depth once, then each zone's precipitation rate and type, and it works out run time zone by zone, splits any zone that needs cycle and soak into shorter cycles, and totals the program length. For a single-zone homeowner question without building a full program, see the how long to water lawn calculator; for which days to water rather than how long, see the lawn watering schedule calculator.
How this sprinkler run time calculator works
1. Run time needed per zone
Run time
Run time (minutes) = (Target depth ÷ Precipitation rate) × 60
2. Cycle and soak, where a zone needs it
The EPA WaterSense program's cycle-and-soak guidance has you test each zone for the point where water starts pooling or running off, which sets that zone's maximum single-cycle run time; if the needed run time is longer than that, split it into multiple shorter cycles with a soak period between them.
Cycles (only if a max single-cycle run time is given and exceeded)
Number of cycles = ROUNDUP(Run time needed ÷ Max single-cycle run time)
Minutes per cycle = ROUNDUP(Run time needed ÷ Number of cycles)
3. Zone total and program length
Zone total time
Zone total = (Minutes per cycle × Number of cycles) + (Soak time × (Number of cycles − 1))
Zones are assumed to run one after another, so the total program length is the sum of every zone's total time; if you enter a start time, the finish time is the start time plus that total.
When this calculator isn't the right tool
Use a different approach for:
- A single-zone homeowner question without a full multi-zone program. See the how long to water lawn calculator.
- Which days to water, rather than how long. See the lawn watering schedule calculator.
- Finding a zone's precipitation rate before you can fill this in. See the sprinkler precipitation rate calculator.
Sprinkler run time calculation example
A 0.5 in target depth, 30-minute soak time, program starting at 6:00 AM, with two zones:
- Zone 1 (spray, PR 1.5 in/hr, max single-cycle run time 5 min): Run time needed = (0.5 ÷ 1.5) × 60 = 20 min. Cycles = ROUNDUP(20 ÷ 5) = 4. Minutes per cycle = ROUNDUP(20 ÷ 4) = 5 min. Zone total = (5 × 4) + (30 × 3) = 20 + 90 = 110 min.
- Zone 2 (rotor, PR 1.0 in/hr, no max cycle entered): Run time needed = (0.5 ÷ 1.0) × 60 = 30 min. No cycling → zone total = 30 min.
- Total program length: 110 + 30 = 140 minutes (2 h 20 min). Finish time: 6:00 AM + 140 min = 8:20 AM.
The same idea in metric
A 12 mm target depth, one zone at 25 mm/hr, no cycling needed, starting at 5:00 AM:
- Run time needed: (12 ÷ 25) × 60 = 28.8 → rounded up to 29 min.
- Finish time: 5:00 AM + 29 min = 5:29 AM.
Both examples use the exact formulas the calculator runs; enter your own program's numbers above for your result.
Practical guidance
Get each zone's precipitation rate right before building the program; Texas A&M AgriLife Extension notes precipitation rates commonly range from about 0.5 to more than 1.5 inches per hour depending on sprinkler type, pressure and spacing, so a guessed figure can throw off run time substantially. The sprinkler precipitation rate calculator works this out from head flow and spacing if you don't already have it.
To find a zone's maximum single-cycle run time, EPA WaterSense's cycle-and-soak guidance has you simply run the zone and time how long it takes before water starts pooling or running off the surface; that's the number to enter here. Leave it blank for zones that never show runoff at their full needed run time, such as many zones on sandy or well-drained soil, since no cycling is needed there.
Check local watering rules. Many water utilities set watering days, hours or restrictions, especially during drought. Where those apply, they take priority over any program built here.
What changes the program
| Factor | Effect | What to check |
|---|---|---|
| Precipitation rate | A higher rate needs less run time for the same target depth, and vice versa. | Use the actual rate for that zone's heads and spacing. |
| Target depth | A larger target scales run time (and total program length) up proportionally. | Base it on your ET-based watering recommendation, not a guess. |
| Max single-cycle run time | A shorter max cycle means more, shorter cycles for the same run time. | Base it on an observed runoff test for that zone, not an assumption. |
| Soak time | Longer soak time extends the zone's total time without changing how much water is applied. | 30-60 minutes is typical EPA WaterSense guidance. |
| Number of zones | Each additional zone adds its own total time to the program, since zones run sequentially. | Confirm whether your controller can run zones simultaneously, which this calculator doesn't assume. |
Frequently asked questions
How do I calculate sprinkler run time for each zone?
Divide the target depth of water by the zone's precipitation rate, then multiply by 60 to convert hours to minutes: Run time (minutes) = (Target depth ÷ Precipitation rate) × 60. Each zone needs its own run time because different sprinkler types and spacings apply water at different rates.
What are good sprinkler timer settings if I have to guess my precipitation rate?
Don't guess if you can avoid it. Texas A&M AgriLife Extension notes precipitation rates for irrigation systems commonly range from about 0.5 to more than 1.5 inches per hour depending on sprinkler type, pressure and spacing, so a guessed value can be off by a factor of three or more. Use the sprinkler precipitation rate calculator with your actual head flow and spacing, or a catch-can test, instead.
How do I set sprinkler zones on a controller for cycle and soak?
The EPA WaterSense program's cycle-and-soak guidance describes splitting each zone's total run time into shorter cycles no longer than the time it takes for water to begin pooling on that zone, with roughly 30 minutes to an hour of soak time with the water off between cycles, repeated until the full scheduled run time has been delivered. Most modern controllers have a built-in cycle-and-soak or multiple-start-times feature for exactly this.
How do I know if a zone needs cycle and soak?
The EPA WaterSense program's cycle-and-soak guidance recommends running a zone and timing how long it takes before water begins pooling or running off; that time is the zone's maximum single-cycle run time. If your target run time is longer than that, split it into cycles; if it's shorter, cycle and soak isn't necessary for that zone.
Why does a spray zone need less run time than a rotor zone for the same amount of water?
Spray heads typically apply water faster (a higher precipitation rate) than rotors, which throw water further and take longer to cover the same area with the same depth. Colorado State University Extension gives an example of pop-up spray heads applying roughly 1¾ inches per hour against about ½ inch per hour for rotor heads, so a rotor zone commonly needs several times the run time of a spray zone for the same depth.
How much time should I leave between cycles?
The EPA WaterSense program's cycle-and-soak guidance suggests roughly 30 minutes to an hour with the water off between cycles, long enough for the applied water to soak in before the next cycle starts.
This gives me one zone's run time; what if I just want a quick answer for my whole lawn?
For a single-zone homeowner question without building a full multi-zone program, the how long to water lawn calculator answers that directly.
See the how long to water lawn calculator.
This tells me how long to run each zone; how do I know which days to water?
This calculator covers run time and cycle splits, not a weekly watering calendar. See the lawn watering schedule calculator for which days to water.
See the lawn watering schedule calculator.
Who built and checked this calculator
Licensed Professional Engineer and Irrigation Association Certified Irrigation Designer with more than 20 years in irrigation design, system auditing and landscape water management. Full profile
How this page was checked
- Both worked examples, including the cycle-split arithmetic and the finish-time calculation, were verified by hand and traced against the code.
- The cycle-and-soak approach and its recommended soak-time range are checked against EPA WaterSense's own program guidance.
- An edge case where a max single-cycle run time is entered but not exceeded was tested to confirm the program correctly does not split that zone into extra cycles.
Sources
- U.S. Environmental Protection Agency, WaterSense program. Cycle and Soak: A WaterSense How-To Guide (cycle-and-soak method, soak-time guidance, and testing for a zone's maximum single-cycle run time).
- Texas A&M AgriLife Extension. Preventing Water Runoff with Cycle and Soak Irrigation (AGEN-PU-218) (typical precipitation rate range, cycle-and-soak worked example).
- Colorado State University Extension. Methods to Schedule Home Lawn Irrigation (typical spray vs. rotor precipitation rates).