Water Supply Industry Interpretations and Advice

  • Area of Interest : Installation
  • Topic : Irrigation systems
  • Title : Guidance for installers of irrigation systems
  • Clause Reference : Schedule 2 paragraph 15 & G15.3
  • Reference Number : I31
  • Decision Date : January 2012

If any of the water in a non-domestic irrigation system is derived from the public mains then the Water Supply (Water Fittings) Regulations, Byelaws in Scotland, apply, which means that the supply feeding the system needs to be protected against backflow and the water used should not be wasted, misused or unduly consumed.

This interpretation applies to non-domestic irrigation systems only: to comply with the requirements of the Regulations/Byelaws:-

  1. Water suppliers have to be notified and agree to the installation or modification of irrigation systems installed in non-domestic installation.
  2. As irrigation systems which utilise sprinkler heads less than 150mm above ground level are a fluid category 5 risk the supply feeding these systems must be through a fluid category 5 backflow protection arrangement such as a Type AA or AB air gap arrangement.
  3. Where a system is drained down during the winter months, with the water supplier’s agreement supply pipes may be laid at a shallower depth than 750mm.
  4. Irrigation systems, with the exception of seep hose systems, should be pressure tested and capable of withstanding 1½ the system maximum operation pressure.
  5. To avoid the risk of cross connection with other supplies irrigation system pipework should be clearly identifiable. It is recommended that the identification advice given in WRAS Information & Guidance Note 9.02.05 ‘Marking & Identification of Pipework for Water Reuse Systems’ be followed and suitable labelling identifying the pipework as an irrigation system applied.