Lawn Watering Calculator
Minutes per zone and gallons to hit 1 inch of water a week.
Enter your values
ⓘ Live results
Results
- Total weekly run time
- 120 minutes
- Per session
- 60 minutes x 2 days
- Water used per week
- 2,492 gallons
- Weekly water cost
- $12.46
- Monthly cost
- $53.95
Working
- 11 in / 0.5 in/hr = 2 hr = 120 min
Quick answer
Run time = target inches divided by the sprinkler precipitation rate. One inch over 1,000 sq ft is about 623 gallons.
minutes = inches / rate x 60; gallons = 0.623 x area x inches
How to use the Lawn Watering Calculator
- 1Find your precipitation rate with the tuna-can test: place cans, run 15 minutes, measure depth and multiply by four.
- 2Aim for about 1 inch per week including rainfall.
- 3Water deeply on fewer days to push roots down rather than sprinkling daily.
Worked example
Using the values the calculator loads with:
Inputs
- Lawn area4000 sq ft
- Water per week1 in
- Precipitation rate0.5 in/hr
- Watering days per week2
- Water price per 1,000 gal5 $
Results
- Total weekly run time120 minutes
- Per session60 minutes x 2 days
- Water used per week2,492 gallons
- Weekly water cost$12.46
- Monthly cost$53.95
- 1 in / 0.5 in/hr = 2 hr = 120 min
Frequently asked questions
Is 1 inch a week right for every lawn?
It is a good default for cool-season grass. Sandy soil wants smaller, more frequent doses; clay wants slow cycles to avoid runoff.
When should I water?
Early morning. Evening watering leaves blades wet overnight and invites fungal disease.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.