Per Capita Water Supply Calculator

Work out per capita water supply instantly with clear inputs, formula shown and shareable results.

About Per Capita Water Supply Calculator

Per capita supply is volume supplied into the distribution system divided by population. Billed per capita consumption is always lower, and the gap is non-revenue water. Reporting both prevents the common error of interpreting high supply per capita as high consumption when it is actually high leakage.

Formulas

Per capita supply

Litres per person per day = supplied volume (m3) x 1000 / population

Non-revenue water

NRW % = (supplied - billed) x 100 / supplied

Worked example

With the default values below, Per Capita Water Supply Calculator returns Per Capita Supply of 170.000. Change any input above and every figure here is recalculated in your browser.

Inputs used

Volume Suppliedminimum 0 m3/day: 8,500 m3/day
Population Servedminimum 0: 50,000
Service Connectionsminimum 0: 9,500
Volume Billedminimum 0 m3/day: 6,800 m3/day

Results

Per Capita Supply: 170.000
Billed Per Capita Consumption: 136.000
Supply Per Connection: 894.74
Non-Revenue Water: 20.000%

Step by step

1Values used
2Per capita supply
3Non-revenue water
4Per Capita Supply= 170.000
5Billed Per Capita Consumption= 136.000
6Supply Per Connection= 894.74
7Non-Revenue Water= 20.000

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

What is a reasonable service level?

The World Health Organization considers 50-100 litres per person per day sufficient for most health and hygiene needs, with 20 litres the absolute minimum. Urban design standards are typically higher.

Is non-revenue water the same as leakage?

No. It also includes unbilled authorised consumption such as firefighting, and apparent losses from meter under-registration and unauthorised connections. Real losses are only one component.