Water Supply and Sanitation in England and Wales - Efficiency (Water Losses)

Efficiency (Water Losses)

Efficiency of service provision has many dimensions, of which only one (water losses) is treated here.

According to OFWAT leakage in England and Wales has declined significantly from 228 litres/property/day in 1994-95 to 141 l/p/d in 2006-07, enough to supply the needs of 10 million people. According to the Environment Agency, many companies in the UK have reduced their water loss to the economic level of leakage. This is the level at which, in the long-term, the marginal cost of leakage control is equal to the marginal benefit of the water saved. The rate of reduction in leakage has slowed for many companies because the most obvious causes of leakage have been detected and addressed, leaving only less apparent leakage problems. Models have been developed and fine-tuned to assess the economic level of leakage. A summary of the debate on these models can be found in a recent report by OFWAT.

According to a comparative study commissioned by the German water industry association BGW average water losses in the distribution network in England and Wales have been estimated at 19 percent. They are lower than in France (26 percent) or Italy (29 percent), but higher than in Germany, where they are apparently only 7 percent. The study states that its methodology allows for an accurate comparison, including water used to flush pipes and for firefighting. This is consistent with the International Water Association's definition of non-revenue water, which includes authorized non-metered consumption such as for flushing and firefighting.

OFWAT does not use percentage figures when it assesses leakage levels. Also it assesses only leakage and not broader losses. It is thus difficult to compare figures from the comparative study cited above with OFWAT figures for England and Wales.