Water Bill Calculator
Estimate your monthly and yearly water bill from gallons used, the rate per 1,000 gallons and fixed fees.
How it works
usage charge = gallons ÷ 1,000 × price · monthly = usage charge + fixed fee · yearly = monthly × 12
Water is metered per 1,000 gallons, so gallons used divided by 1,000 times the rate gives the usage charge. Most bills add a fixed monthly service fee on top regardless of use, so that’s included before annualizing. Many utilities also bill sewer as a share of water use, which can roughly double the effective cost — check whether your quoted rate already includes it.
Worked example
6,000 gallons at $5.00 per 1,000 gallons is $30.00 of usage. Add a $15.00 fixed monthly fee and the bill is $45.00 a month — about $540 a year, an all-in $7.50 per 1,000 gallons.
Frequently asked questions
Where do I find gallons used and my rate?
Both are on your utility bill: usage is often listed in gallons or in “units” (frequently 748 gallons per hundred-cubic-foot unit, or 1,000 gallons per unit — the bill says which), and the rate per 1,000 gallons and the service fee are itemized in the charges section.
Does this include sewer charges?
Only if you fold them into the rate. Many bills charge sewer as a percentage of metered water, which can nearly double the real cost of each gallon — enter a combined rate if you want the true all-in number.
How much water does a household use?
A typical US household uses around 8,000–12,000 gallons a month, but it varies widely with lawn watering, family size and fixtures. Toilets, showers and outdoor irrigation are the biggest levers if the bill looks high.
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This calculator is for educational purposes. Double-check important results before acting on them.