asked the Secretary of State for the Environment what is the average percentage of water lost through leakage in England for the last available year; and if he will give the average for each water authority.

I have no reliable estimates of the percentage of water lost through leakage in England, but a survey in 1977 showed that, on average, approximately 24 per cent. of water supplied in Great Britain was unaccounted for and leakage must have been the major factor.