The Water Regulations permit the re-introduction of dual-flush WC flushing cisterns. Installed and used correctly they can achieve considerable water savings.
The Regulations require a reduced maximum volume of water flushed in newly installed WC cisterns – from seven and a half litres down to six litres. There is no prescribed lower limit. Only those flushing devices which meet the stringent specification approved by the Regulator will be allowed. These include drop valves. Mains pressure flushing valves and pressure flushing cisterns which are permitted in certain non-domestic premises.The Water Supply Industry encourages the use of displacement devices in existing flushing cisterns provided they do not lead, by repeated flushing, to a greater water use. There are proprietary devices available as alternatives to ‘the brick in the WC cistern’ but they must be used judiciously. Their installation must not result in additional flushing to remove faecal material nor must the displacement device impede the action of the float operated valve.
The Regulator has modified the Regulations by means of a relaxation to permit the retro-fitting of dual and interruptible flushing devices to WC cisterns which were installed before 1 July 1999. Retro-fit devices must not alter the available full flush volume and must meet the relevant parts of the current Regulators’ WC Performance specification.
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Information Updated on: 2 February 2012
