How to Calculate Lawn Irrigation Water Usage and Costs
To provide your lawn with one inch of water takes a little over half a gallon per square foot (0.623 gallon to be more exact). That means that every 10’x10’ area will require over 62 gallons of water. That doesn’t sound like much until you consider that a 100’ x 100’ lawn uses 6,230 gallons of water every time you turn on the sprinklers!
This assumes that your yard is square or rectangular. For more unusual shapes, you’ll have to dig out your old high school geometry book to come up with the amount of area involved.
To calculate the cost of watering your yard, divide the number of gallons used by 1,000 then multiply by the price you pay per 1,000 gallons (see our calculator below). Don’t forget to include the sewer costs unless you have a separate meter.