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Household Water Usage from Fixtures Calculator

Daily gallons = Σ (uses × flow rate × duration).

Estimate a household's daily water usage in gallons from typical fixture flow rates and use frequencies: toilets (1.6 gal/flush), showers (2.0 gal/min), bathroom faucets (1.5 gal/min), dishwasher (4 gal/load), and clothes washer (15 gal/load).

Marcus Laurent By Marcus Laurent
Published Last reviewed 1 min read

Inputs

Results

Enter values and click Calculate to see results.
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How to use this calculator

  1. Fill in the inputs above using the units you already have.
  2. Values update automatically as you type — no submit button needed.
  3. Hover any result row for the underlying formula and intermediate values.

Formula

Gallons/day = toilet_flushes·1.6 + shower_min·2.0 + faucet_min·1.5 + dishwasher_loads·4 + laundry_loads·15.

In depth

Estimate a household's daily water usage in gallons from typical fixture flow rates and use frequencies: toilets (1.6 gal/flush), showers (2.0 gal/min), bathroom faucets (1.5 gal/min), dishwasher (4 gal/load), and clothes washer (15 gal/load).