How many times does a person flush per day?

The average person flushes about 5-6 times per day. A household of 2-3 people averages 10-15 flushes daily.

How much can a low-flow toilet save?

Replacing a 3.5 GPF toilet with a 1.28 GPF model saves about 9,700 gallons per year for a typical household, cutting toilet water use by 63%.

Do dual-flush toilets save water?

Yes. Dual-flush toilets use 0.8 gallons for liquid waste and 1.6 for solid. Since most flushes are for liquid, average use drops to about 1.0 GPF effectively.

Toilet Water Calculator

Calculate annual water usage and cost from toilet flushing based on flushes per day and gallons per flush.

Save

Flushes per Day (Household)

Gallons per Flush

gallons

Water Rate

USD/1000 gal

Annual Toilet Water

7,008 gallons

Annual Cost35.04 USD

Savings with 1.0 GPF Toilet13.14 USD

Daily Use19.2 gallons

Annual Toilet Water vs Water Rate

View formula & how it works →

How to Calculate Toilet Water Usage

Toilets are the single largest indoor water user, accounting for about 24% of household water.

Formula

Annual Gallons = Flushes/Day * GPF * 365

Gallons per Flush by Age

Pre-1980 toilets: 5-7 GPF

1980-1994: 3.5 GPF

1994+ federal standard: 1.6 GPF

WaterSense (current): 1.28 GPF

Ultra low-flow: 0.8-1.0 GPF

Example Calculation

12 flushes/day with 1.6 GPF toilet at $5/1000 gal water rate.

01Daily water: 12 * 1.6 = 19.2 gallons
02Annual water: 19.2 * 365 = 7,008 gallons
03Annual cost: 7,008 * $5 / 1,000 = $35.04
04Savings with 1.0 GPF: (1.6-1.0) * 12 * 365 * $5 / 1,000 = $13.14

Toilet Water Calculator

How to Calculate Toilet Water Usage

Formula

Gallons per Flush by Age

Example Calculation

Frequently Asked Questions

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