Water Savings Calculator
Compare a baseline and a reduced monthly usage figure to see the gallons and dollars a change — a rain barrel, a fixed leak, a fixture swap — is actually worth.
Savings estimate
How the estimate works
The gallons saved per month is simply your baseline usage minus your reduced usage, projected to a year by multiplying by 12. To turn that into a dollar figure, the calculator combines your water rate and any sewer rate (many utilities charge sewer service based on metered water use) into one combined rate per 1,000 gallons, then applies it to the gallons saved.
The percent-reduction figure is the gallons saved divided by the baseline, which is useful for comparing the impact of different changes — a rain barrel offsetting irrigation, a fixed leak, or a fixture swap — on a common scale regardless of your household’s starting usage.
Frequently Asked Questions
Why does the calculator ask for a sewer rate too?
Many water utilities calculate a sewer or wastewater charge based on how much metered water you use, not on separate metering of what goes down the drain — so a reduction in water use often lowers both charges at once. Adding your sewer rate alongside your water rate gives a more complete picture of the dollar savings than the water rate alone.
Where do I find my baseline and reduced usage figures?
A water bill typically states usage in gallons or in units like CCF (hundred cubic feet, 1 CCF ≈ 748 gallons) or cubic meters (1 m³ ≈ 264 gallons) — convert to gallons first if needed. The household water-use calculator on this site can also produce an estimated baseline if you don't have a bill handy.
What counts as 'reduced usage' for this calculator?
Anything that lowers your metered water draw: a rain barrel offsetting outdoor irrigation, a fixed leak, a low-flow fixture swap, or a shorter shower habit. Enter your new expected monthly total after the change, and the calculator handles the rest.
Why can't reduced usage be higher than baseline?
This tool is built specifically to estimate savings from a reduction, so it expects the reduced figure to be at or below the baseline. If your usage went up instead of down, compare the two numbers directly rather than running them through a savings calculator.
Planning estimate only, based on the rate and usage figures you enter. Actual savings depend on your utility's billing structure, which can include tiered rates and fixed fees not modeled here.