Regulation 4(1)(a) & 4(2): Overview

How will I know if a water fitting is suitable for installation?

Establishing whether a water fitting is suitable for installation is dependent upon a number of factors including but not limited to:

  • System design, things considered include but are not limited to compatibility:
    • with other water fittings within a plumbing system (e.g the potential for galvanic action)
    • system operational parameters (e.g. the maximum* and minimum pressure, temperature and flow the systems will be operating at)
  • Location specific factors, things considered include but are not limited to:
    • the environment (e.g. ground or airborne contamination, the risk of frost damage, corrosion or dezincification)
    • product installation requirements and/or constraints (e.g. installed where light is excluded or only above ground)
    • installation backflow risks (e.g. the need for backflow protection to be installed)

If the proposed plumbing work is notifiable, the suitability of water fittings will be assessed as part of the notification process. 

If the installation is not notifiable there remains a legal obligation for the installer and premises owner or occupier to ensure the plumbing work is fully compliant with the water fittings regulations in England, Wales and Northern Ireland, byelaws in Scotland. Therefore, if in doubt, contact the local water undertaker for advice.


*P​lease note all water fittings must be capable of withstanding an internal water pressure of not less than 1½ times the maximum pressure it will be subject to in operation.



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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.