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Water Bill Calculator

Estimate a household water bill from showers, laundry, dishes and a dripping tap.

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About the Water Bill Calculator

Estimates household water use from how the fixtures are actually used, then applies your rate. The breakdown is the useful part: showers and toilets usually dominate, and seeing the split tells you where a change would make a difference.

Toilets are where the biggest single saving usually sits. A pre-1994 US toilet uses 3.5 gallons or more per flush against 1.6 for a modern one — for a household of four that is over 13,000 gallons a year from one fixture.

Most bills also charge for sewer, usually as a multiple of the water used, so the real bill is often close to double the water figure alone. A tap dripping once a second wastes about five gallons a day — 1,800 a year, from a washer that costs pennies.

How it works

  1. Set how many people live there and how often each fixture is used.

  2. Enter your rate per 1,000 gallons — it is on the bill.

  3. You get daily and monthly usage, the bill, and where the water goes.

Frequently asked questions

How much water does a shower use?
About 2.1 gallons a minute for a modern low-flow head, so an eight-minute shower is roughly 17 gallons. Older unrestricted heads can use two or three times that.
How much water does a dripping tap waste?
About five gallons a day at one drip per second — around 1,800 gallons a year. The washer that fixes it costs pennies, which makes it the best-value repair in most homes.
How much does a toilet flush use?
1.6 gallons for a post-1994 US toilet and 3.5 or more for an older one. For a household of four, replacing an old toilet saves over 13,000 gallons a year.
Why is my water bill higher than this estimate?
Because most bills also charge for sewer, often as a multiple of water used, plus standing charges. The real total is frequently close to double the water figure alone.
What uses the most water in a home?
Toilets and showers typically dominate indoor use, followed by laundry. Outdoor watering can exceed all of them combined in summer, which is why bills are seasonal.

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