Backflow arising from connections between potable (drinking) water and non-potable water can constitute a serious public health hazard.

The Water Supply (Water Fittings) Regulations 1999 for England & Wales and the Water Byelaws 2000 (Scotland) detail the rules & requirements for the installing & use of RPZ Valves as backflow prevention devices.

The local Water Supplier must approve the installation. Diamond Plumb Ltd / can obtain the approval on behalf of the customer.

Only approved RPZ valves & fittings must be used (see list of approved valves supplied by Diamond Plumb HERE).

The RPZ valve must be serviced, tested & maintained in accordance with the Water Supplier’s requirements, usually annually.

RPZ Valves (sometimes referred to as type BA devices) can protect against backflow at the point of use from a possible contamination of fluid up to Category 4. RPZ valves should not be used in Category 5 situations, such as mortuary or embalming, commercial agricultural insecticide or fertiliser applications and reclaimed water systems.

Honeywell-BA300Specific instructions relating to the INSTALLATION OF RPZ VALVES should be followed, basically:

  • The Installation and use of RPZ valves must be notified in advance
  • All RPZ valves reduce the water pressure available ( this varies according to the Make / Model used )
  • Only UK approved RPZ valves can be legally fitted
  • RPZ valves should only be tested & certified by an Accredited UK RPZ VALVE TESTER
  • The RPZ valve should not be fitted in areas that are liable to flooding
  • RPZ valves should not be fitted above Electrical Equipment
  • RPZ valves must not be in a concealed compartment
  • They should not be exposed to frost or freezing conditions ( unless protected from freezing )
  • In the UK only Horizontal fitting of RPZ valves is appropriate.
Copyright © 2015 Diamond Plumb Limited.
Scroll to Top