How to use this calculator
Select your sprinkler type (fixed spray, rotor, MP rotator, or drip), your grass type, soil type, sun exposure level, and current season. Each of these factors affects how much water your lawn needs and how quickly your sprinklers deliver it.
The calculator combines your sprinkler head precipitation rate with your lawn's actual water needs to determine the exact run time per session. It also tells you how many sessions per week to water and whether you need cycle and soak breaks to prevent runoff on clay soils or slopes.
Review the weekly schedule in the results to see total minutes per zone. If the recommended run time seems long, check that you selected the correct sprinkler type, as rotors and MP rotators deliver water much more slowly than fixed spray heads and naturally require longer run times.
Sprinkler precipitation rates
| Type | Rate (in/hr) | Best for |
|---|---|---|
| Fixed Spray | ~1.5 | Small areas, narrow strips |
| Rotor | ~0.5 | Large open lawns |
| MP Rotator | ~0.4 | Slopes, clay soils, mixed zones |
| Drip | ~0.6 | Beds, gardens, trees |
Frequently asked questions
How long should I run my sprinklers?
It depends on your sprinkler type. Fixed spray heads deliver about 1.5 inches per hour, so 20 minutes provides about half an inch. Rotors deliver 0.5 inches per hour, so they need about 60 minutes for the same coverage. Use this calculator with your specific setup for an accurate recommendation.
How often should I water my lawn?
Two to three times per week is ideal for most lawns. Deep, infrequent watering builds deeper roots than daily light sprinkling. Watering every day can actually harm your lawn by keeping the root zone constantly saturated and promoting shallow root growth.
What is cycle and soak?
Cycle and soak means running sprinklers in short bursts with breaks in between. This prevents water from running off before it soaks into clay soil or slopes. Run for 10 to 15 minutes, wait 30 minutes, then run again until you reach your total needed time.
What are signs of overwatering vs underwatering?
Overwatering: mushy soil, mushrooms, yellow patches despite wet ground. Underwatering: grass blades fold inward, blue-gray color, footprints stay visible. When in doubt, stick a screwdriver into the soil. If it slides in easily to 6 inches, you have enough moisture.