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Water Bill Calculator

Use this free water bill calculator to estimate your monthly water bill. Enter your usage in gallons, CCF, or cubic meters, choose a flat rate or tiered rates, add your base fee and sewer charge, and see the full breakdown — plus how your usage compares with a typical household.

How it works

A water bill has three parts, and only the first one depends on how much water you use. The water charge pays for the volume itself. The base fee, also called a service fee, is a fixed monthly charge that covers the meter, the pipes, and keeping the system running — you pay it even if you use no water at all. The sewer charge pays for treating the wastewater that leaves your home. Add the three together and you have the monthly bill, before any local taxes or surcharges your utility may add.

Usage is measured in different units depending on where you live, so the calculator accepts all three common ones. Gallons are the most familiar in the United States. A CCF is 100 cubic feet, equal to 748 gallons, and many utilities bill in CCF — if your bill says 8 CCF, you used about 5,984 gallons. A cubic meter is 264.172 gallons and is the standard unit in most of the rest of the world. Whatever unit you enter, the calculator converts it to gallons first and does all the pricing from there.

With a flat rate, the water charge is simple: usage divided by 1,000, multiplied by the rate per 1,000 gallons. At $5.50 per 1,000 gallons, 6,000 gallons costs $33.00. With tiered rates, the price per unit rises as usage rises. The first block of usage is charged at the lowest rate, the next block at a higher rate, and anything above the top limit at the highest rate. Tiered pricing is designed to make heavy use — usually lawn watering and pools — more expensive, which encourages conservation. The default tiers here are $4.00 for the first 3,000 gallons, $6.00 up to 8,000 gallons, and $8.00 above that, but you can change every limit and rate to match your own utility.

The sewer charge is usually tied to water use, because most water used indoors ends up in the sewer. The common method is a percentage of the water charge — 50% is a typical figure, so a $33.00 water charge adds a $16.50 sewer charge. Some utilities charge a flat monthly sewer amount instead, and some homes on septic systems pay no sewer charge at all. Pick the method that matches your bill.

The household comparison puts your usage in context. A typical person uses about 3,000 gallons a month, so a two-person household usually lands near 6,000 gallons and a family of four near 12,000. If your per-person usage is far above that, look for the usual culprits first: a running toilet, a dripping faucet, an irrigation system running too often, or a hidden leak. A single toilet that runs constantly can waste thousands of gallons in a month — often more than the rest of the household combined.

Worked example

A two-person household uses 6,000 gallons in a month. Their utility charges a flat $5.50 per 1,000 gallons, a $15.00 base fee, and a sewer charge of 50% of the water charge.

Step 1: The water charge is 6,000 ÷ 1,000 × $5.50 = $33.00.
Step 2: The base fee is $15.00.
Step 3: The sewer charge is $33.00 × 50% = $16.50.
Step 4: The total bill is $33.00 + $15.00 + $16.50 = $64.50.

The result: a $64.50 monthly bill, or $10.75 per 1,000 gallons all-in, and 3,000 gallons per person — right at the typical level for a two-person household. Try the tiered option with 10,000 gallons: the water charge becomes $58.00, the sewer charge $29.00, and the total $102.00.

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