|6.1||Non Revenue Water||Difference between water supplied and water sold (i.e. volume of water “lost”) expressed as a percentage of net water supplied||%|
|6.2||Non Revenue Water||Volume of water “lost” per km of water distribution network per day||m3/km/day|
|6.3||Non Revenue Water||Volume of water “lost” per water connection per day.||m3/conn/day|
Non revenue water represents water that has been produced and is “lost” before it reaches the customer (either through leaks, through theft, or through legal usage for which no payment is made). Part of this “lost” water can be retrieved by appropriate technical and managerial actions. It can then be used to meet currently unsatisfied demand (and hence increase revenues to the utility), or to defer future capital expenditures to provide additional supply (and hence reduce costs to the utility).
The IWA distinguish between non revenue water (%) and unaccounted for water, with the latter not including legal usage that is not paid for. The indicators are usually measured in m3/conn/day. The difference is usually small, and the IBNET Toolkit therefore only uses non revenue water as an indicator.
There is a debate as to the most appropriate measure of non revenue water. A percentage approach can make utilities with high levels of consumption, or compact networks, look to be better performing than those with low levels of consumption or extensive networks. To capture these different perspectives the reporting of three measures of non revenue water has become the norm.