§ Mr. Dalyellasked the Secretary of State for the Environment what estimates he has made of the average number of sewer collapses per day.
§ Mr. Giles ShawIn 1981, 3,228 sewer failures in England and Wales were reported to the water research centre, of which 2,177 (six per day) were collapses. 73 per cent. of failures concerned pipes of nine inches (225mm) diameter or less.
§ Mr. Dalyellasked the Secretary of State for the Environment what estimates are available to him of the annual cost of maintaining the sewerage system over the next 10 years.
§ Mr. Giles ShawTaking 'maintenance' to refer to water authorities' revenue expenditure on the sewerage system, the most recent published accounts of the water authorities for 1981–82 show some £50 million spent in that year for this purpose in England and Wales. There are no projections available for this element of expenditure over the next 10 years.
§ Mr. Dalyellasked the Secretary of State for the Environment approximately how many miles of (a) public and (b) private sewers there are, and in each case, what is his estimate of the length in need of urgent repair.
§ Mr. Giles ShawThe total length of public sewers in England and Wales is about 138,000 miles. Water authorities are proceeding with surveys of those parts of these systems considered to be most critical. These surveys are continuing and results have not generally been published. However one authority, Severn-Trent, has estimated on a sample basis that about two per cent. of its332W system may be unsound although that does not necessarily indicate a need for urgent repair. Information on the length and condition of private sewers is not available.
§ Mr. Dalyellasked the Secretary of State for the Environment what percentage of 100-year-old sewers are deemed defective; what percentage of 80-year-old sewers are deemed defective; and what percentage are being repaired.
§ Mr. Giles ShawThe information requested is not available but some 15 per cent. of United Kingdom sewers are over 100 years old.