Letter: Unknown waste of water

Sir: As a former senior water engineer of the pre-privatisation era I am concerned to see how the leakage rates of the various water companies are being generally quoted as though they were gospel. Matthew Taylor in his article "Lessons in how to run water" (19 May) is the latest politician to quote a 30 per cent leakage figure as though it were a proven fact.

Until there is metering of all supplies no one can say how much water is lost in the distribution system. The present means of arriving at leakage is by estimating the daily unmetered consumption of each household and making other basic assumptions on legitimate uses: the estimated leakage is then the difference between those totals and the amounts supplied into the system. An Ofwat report of May last year made it clear that there are "significant uncertainties in leak reporting".

By all means ensure that the water companies reduce their wastage of water in these times of drought, but let us have some caution in the figures quoted.

JOHN FAIRBANK

Hove, East Sussex