Fictional worked example

Build a four-person household water estimate

Showers and toilet flushes are counted per person; shared kitchen tap use and laundry are counted once for the household. Add the separate daily averages to estimate the listed activities.

Open Calculator

Inputs and calculation

Showers
Tool inputValue
CurrencyUSD
Volume or billing unitm³
Activity measurementFlow over time
Flow (L/min)8
Minutes per occurrence6
Occurrences per person per day1
People (1 for shared use)4
Days or equivalent sessions30
Price per billing unit (USD)3

8 L/min × 6 min × 1 × 4 × 30 = 5760 L. Divide by 1,000 for m³ and multiply by 3 for USD 17.28.

Tool result · USD 17.28

Toilet
Tool inputValue
CurrencyUSD
Volume or billing unitm³
Activity measurementFixed volume per event
Liters per event5
Occurrences per person per day4
People (1 for shared use)4
Days or equivalent sessions30
Price per billing unit (USD)3

5 L per event × 4 × 4 × 30 = 2400 L. Divide by 1,000 for m³ and multiply by 3 for USD 7.20.

Tool result · USD 7.20

Shared kitchen tap
Tool inputValue
CurrencyUSD
Volume or billing unitm³
Activity measurementFlow over time
Flow (L/min)6
Minutes per occurrence10
Occurrences per person per day1
People (1 for shared use)1
Days or equivalent sessions30
Price per billing unit (USD)3

6 L/min × 10 min × 1 × 1 × 30 = 1800 L. Divide by 1,000 for m³ and multiply by 3 for USD 5.40.

Tool result · USD 5.40

Shared laundry
Tool inputValue
CurrencyUSD
Volume or billing unitm³
Activity measurementFixed volume per event
Liters per event60
Occurrences per person per day0.5
People (1 for shared use)1
Days or equivalent sessions30
Price per billing unit (USD)3

60 L per event × 0.5 × 1 × 30 = 900 L. Divide by 1,000 for m³ and multiply by 3 for USD 2.70.

Tool result · USD 2.70

Laundry at 50 L per load
Tool inputValue
CurrencyUSD
Volume or billing unitm³
Activity measurementFixed volume per event
Liters per event50
Occurrences per person per day0.5
People (1 for shared use)1
Days or equivalent sessions30
Price per billing unit (USD)3

50 L per event × 0.5 × 1 × 30 = 750 L. Divide by 1,000 for m³ and multiply by 3 for USD 2.25.

Tool result · USD 2.25

What the comparison shows

The first four rows total 10,860 L and 32.58. Replacing only the laundry row lowers that to 10,710 L and 32.13. Multiplying shared loads by four would overstate the estimate.

Assumptions and limits

The total covers the listed activities. Outdoor use, dishwasher loads and leaks require their own estimates.

Related guides and examples