Water Bill Estimator
Estimate your monthly household water bill based on usage habits, household size, and local water rates.
Identify where you use the most water.
Your household water bill depends on how much water you use and the rate your utility charges per unit. Water is typically billed in one of two units: cubic meters (m³) or hundreds of cubic feet (CCF in the US). One cubic meter = 264 gallons. One CCF = 748 gallons.
The often-quoted US figure of 300 gallons (1,136 litres) a day is per HOUSEHOLD, not per person. That trips people up constantly. Spread across an average family it works out to roughly 80 gallons (300 litres) per person per day, and an efficient household with low-flow fixtures runs closer to 50 gallons (190 litres) each. The per-person figure in your result is measured against that 300-litre benchmark.
Major water uses in a typical household:
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Toilet flushing: 24–30% of indoor water use. Old toilets use 13 litres (3.5 gallons) per flush. WaterSense / dual-flush toilets use 4.8 litres (1.3 gallons).
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Showers: 17–20% of indoor use. Standard shower heads use 9–11 litres/min (2.5–3 gal/min). Low-flow heads: 5.7 litres/min (1.5 gal/min).
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Clothes washing: 15–22% of indoor use. Old top-loader: 150–190 litres (40–50 gallons) per load. HE (high efficiency) front-loader: 50–75 litres (13–20 gallons).
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Faucets (sink, kitchen): 15–19%. Typically 9 litres/min (2.4 gal/min) if no aerator.
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Outdoor watering / irrigation: Can be 30–50% of TOTAL household water use during summer. A typical lawn sprinkler uses 1,000–1,500 litres/hour (250–400 gal/hour).
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Leaks: The US EPA estimates that the average household has leaks accounting for 10% of total water use, about 37,850 litres (10,000 gallons) per year. A dripping faucet at one drip per second wastes 15 litres (4 gallons) per day.
Average US water rates: approximately USD 0.50–2.00 per 264 gallons (per m³ equivalent). Sewer charges are typically 50–100% of the water charge added on top, since most billed water eventually enters the sewer system.
Water rates commonly have a tiered structure: a base service charge plus a per-unit rate that sometimes increases as usage increases (to discourage waste).
How we build and check this calculator
This calculator runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
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