Backflow Protection: FAQs

How should mechanical backflow prevention devices be installed?

Mechanical backflow prevention devices which, depending on the type of device, may be suitable for protection against backpressure or backsiphonage, or both, should be:

  • Accessible for inspection, maintenance and replacement
  • Installed in a workmanlike manner. For example, installed in accordance with any applicable requirements set out in:
  1. Schedule 2 of the water fittings regulations, byelaws in Scotland
  2. The Regulators Specification for backflow
  3. The performance specification the device or arrangement confirms to
  4. Water undertaker AIMs
  5. BS EN 806 and/or BS 8558
  6. Manufacturers instruction
  7. Any conditions of product certification




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Uncontrolled if downloaded. This is informative, non-statutory guidance and intended for general guidance purposes only; it is subject to change.

Compliance with this information should not be relied upon as guaranteeing no enforcement action will be taken by water undertakers. Water Regs UK accepts no liability for loss, indirect or consequential loss arising from or in connection with this guidance document.

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