Lawn Watering Calculator
Estimate weekly water for your lawn. Enter the area in square feet and inches of water per week to see gallons, and add a sprinkler rate for run time.
How to estimate lawn watering
- Enter your lawn area in square feet.
- Enter the inches of water per week your lawn needs.
- Add your sprinkler output in gallons per minute for run time.
Examples
1000 sq ft lawn, 1 inch per week
Area 1000, 1 in, sprinkler 5 gpm
623 gallons per week, about 124.6 minutes of run time
Frequently asked questions
How much water does a lawn need?
Most lawns want about one inch of water per week, including rainfall. In hot or dry weather some grasses need up to one and a half inches, while cool weather needs less.
How many gallons is one inch over a square foot?
About 0.623 gallons. One inch of water over a square foot is one twelfth of a cubic foot, and a cubic foot holds roughly 7.48 gallons.
How do I find my sprinkler's gallons per minute?
Place an empty container under the sprinkler, run it for a set time, then divide the gallons collected by the minutes. Manufacturer specs also list the flow rate.
Is it better to water deeply or often?
Deep and infrequent watering is best for most lawns, as it encourages deeper roots. Water in the early morning to cut evaporation and reduce disease.
Should I subtract rainfall?
Yes. Rain counts toward the weekly total, so a rain gauge helps you water only the shortfall. Skip watering after heavy rain to avoid waste and runoff.
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