Question to the Department for Environment, Food and Rural Affairs:

To ask the Secretary of State for Environment, Food and Rural Affairs, what estimate he has made of the number of off mains drainage properties which use septic tanks in (a) England and (b) Cumbria.

Mains sewerage systems (operated by the Water and Sewerage Companies) cover around 95% of the population of England. Non-mains sewerage systems (including septic tanks or small private sewage treatment works) serve the remaining 5%.

The then Department of Environment conducted a study in 1994 to estimate the number of properties not on mains drainage. It estimated that there were approximately 700-750,000 such properties in England. It further estimated that approximately 85,000 to be within the North West Region. It did not account for specific numbers for Cumbria.

The Environment Agency has recently begun work to understand how many properties are likely served by private sewerage systems. We do not believe that the figures for either England or the North West Region are likely to have changed significantly in the period since the 1994 study.