How Long To
Water Your Lawn
Determine your lawn’s weekly watering needs.
Most require an average of 1 to 1½ inches weekly, but specific watering needs vary by turfgrass type, the specific grass, and time of year.
Figure the water output of your sprinkler system.
To calculate how much water your sprinkler system puts out per hour, place six containers of the same size and shape in one area of the lawn where your sprinklers hit and run your sprinklers for 20 minutes.
If in doubt, use the tuna can method or a flow timer.
Place two empty tuna cans in two different spots the lawn sprinklers hit. Run the sprinklers for 15 minutes. Using a ruler, measure the water depth in each can and take the average of the two measurements.
Calculate how long to water the lawn each week.
To figure out how long your sprinklers should run each week, divide your lawn’s weekly watering needs in inches by your sprinkler’s hourly water output.
Divide weekly sprinkler duration by weekly watering frequency.
This calculation will inform you how long to run your sprinklers each watering session. To grow a healthy lawn, water must reach and be fully absorbed by the grass roots.
To save water (and money), water at the right times.
Many cities have ordinances requiring residents to water only during early morning and evening hours.
Adjust the math to account for rainfall.
On a twice-weekly watering schedule, run your sprinklers 10 minutes each time.