Plumbing systems

This section explains the requirements for installing a new plumbing system under the current water regulations. This includes the fittings, the design of the system and the prevention of backflow.

Meeting the regulations

Plumbing systems must be designed, installed and maintained to meet the Regulations’ requirements.

Plumbing materials and fittings must be of a suitable standard. Although it is not illegal to sell unsuitable fittings and appliances, it would be illegal to install them.

The Regulations list the standards for suitability and the Water Fittings and Materials Directory, published by the Water Regulations Advisory Scheme (WRAS), gives up-to-date details of a wide range of items which have been tested and proved to comply.



Plumbing must be properly installed and maintained to:

  • Protect water quality
  • To ensure safety
  • Allow ease of access for maintenance
  • Allow detection of leakage
  • Give protection against damage or freezing etc.

An approved contractor will guarantee compliance of the new installation.

The Regulations do not apply to existing water fittings. Any plumbing system or water fitting which was installed lawfully under the Water Supply Byelaws before the Regulations came into force on 1 July 1999 can continue to be used, even if its installation would not now be permitted.


Prevention of backflow

Where water or water-using appliances are used with fluids or materials which could contaminate the water supply there must be adequate protection to prevent backflow into other parts of the system.

The Regulations specify five Fluid Risk Categories describing types of contaminant, and detailing the appropriate type of prevention device that must be fitted to guard against backflow of contaminated water.

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