Water Supply Industry Interpretations and Advice

  • Area of Interest : Backflow prevention
  • Topic : Maintaining supplies
  • Title : Cross connections - permissible arrangements
  • Clause Reference : Regulation 5 & Schedule 2 paragraph 15
  • Reference Number : B16
  • Decision Date : February 2002 (Revised September 2005 & February 2015)

This interpretation does not give justification for cross-connections in general.

With the agreement of the local water undertaker, a bypass arrangement may be permitted in specific circumstances, including for maintenance and emergency situations.

Factors that will be taken into consideration by the water undertaker include but are not limited to:

  • the level of risk downstream
  • the system design, in particular the need to minimise stagnation
  • the presence of appropriate point of use backflow protection at terminal fittings
  • the likely duration of the bypass arrangement
  • the design and location of the bypass arrangement
  • the installation of appropriate backflow protection on the bypass arrangement
  • where applicable an agreed method statement and the circumstances under which arrangement this will be applied.   

This arrangement will not normally be acceptable in any situation when a pump capable of delivering any flow rate greater than 12 litres per minute, may become mains fed as a result if the use of a bypass arrangement.