Household water use calculator
Showers and toilets dominate household water use, and both are easy to measure directly.
L/min
L
per cubic metre
Daily household use
648L
- Per person per day
- 162.0
- Annual use
- 236.68
- Annual water cost
- 497.02
- Showers
- 288
- Toilet flushing
- 120
- Showers as a share of the total
- 44.4 %
Show the working
- People in the household = 4
- Shower length = 8
- Shower flow rate = 9
- Toilet flushes per person per day = 5
- Litres per flush = 6
- Other use per person per day = 60
- Water price = 2.1
- Showers = 4 * 8 * 9 = 288
- Toilet flushing = 4 * 5 * 6 = 120
- other = 4 * 60 = 240
- Daily household use = 288 + 120 + 240 = 648
- Per person per day = 648 / 4 = 162
- Annual use = 648 * 365.2425 / 1000 = 236.677
- Annual water cost = 236.677 * 2.1 = 497.022
- Showers as a share of the total = 648 > 0 ? 288/648*100 : 0 = 44.4444
Values are shown to six significant figures here; the arithmetic itself runs on exact fractions and is only rounded where a number is printed.
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The formula
- daily use = showers + flushing + everything else, all per person
Average household use runs 120 to 150 litres per person per day in Europe and about twice that in the United States.