8.For properties built before 1990, where consumers pay on an unmeasured basis for water and sewerage services, their charges are usually calculated by reference to the rateable value of the property. Under section 145 of the Water Industry Act 1991, companies were prevented from continuing to base charges for water and sewerage services on rateable value after 31 March 2000.
Background English and Welsh Provisions Basis of water charging - unmeasured charges