ILI calculator
Enter five numbers and get the Infrastructure Leakage Index, the UARL and your World Bank performance band. For the full IWA water balance with uncertainty, cost and carbon, use the complete calculator.
Real losses come from a water balance; if you only have NRW, run the full calculator to separate apparent losses first.
- UARL
- –
- CARL
- –
- Real losses per connection
- –
- …per m of pressure
- –
How it's calculated
The unavoidable annual real losses are the leakage a well-run network of your size and pressure could not get below: UARL (litres/day) = (18 × Lm + 0.8 × Nc + 25 × Lp) × P, where Lm is kilometres of mains, Nc the number of service connections, Lp kilometres of service pipe between the property boundary and customer meters, and P the average operating pressure in metres. The ILI divides your current annual real losses by that floor. For intermittent supply, both are corrected for hours of supply per day.
Read more: ILI explained · the UARL formula · full methodology.