Water Supply Industry Interpretations and Advice

  • Area of Interest : Backflow prevention
  • Topic : Backflow risk of shower hoses
  • Title : Demarcation between a fluid category 3 and fluid category 5 zone of risk in a bathroom
  • Clause Reference : Schedule 2 paragraph 15 & G15.5
  • Reference Number : B53
  • Decision Date : January 2012 (revised June 2015)

Hoses used in bathrooms must maintain a minimum of an AUK3 tap gap between the shower outlet and any fluid category 5 risk such as bath in highrisk premises or the spillover level of a WC. Where an AUK3 tap gap is required but cannot be maintained either the hose must be appropriately restrained(refer to interpretation B20) or an alternative form of fluid category 5 backflow protection must be installed.

Similarly hoses used in bathrooms must maintain a minimum of an AUK2 tap gap between the shower outlet and any fluid category 3 risk such as the spillover level of a basin or bath in domestic premises. Where an AUK2 tap gapis required but cannot be maintained either the hose must be appropriatelyrestrained (refer to interpretation B20) or an alternative form of fluid category3 backflow protection must be installed.