Toilet Water Calculator — Formule
## 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
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
Exemple Résolu
12 flushes/day with 1.6 GPF toilet at $5/1000 gal water rate.
- Daily water: 12 * 1.6 = 19.2 gallons
- Annual water: 19.2 * 365 = 7,008 gallons
- Annual cost: 7,008 * $5 / 1,000 = $35.04
- Savings with 1.0 GPF: (1.6-1.0) * 12 * 365 * $5 / 1,000 = $13.14