Flexible hose connecting appliances to the water supply are a frequent cause of unacceptable taste in drinking water.

This is down to water in the hose becoming contaminated by chemicals which have leached from it. Water can move from the hose into the pipe supplying the drinking water tap as a result of pressure fluctuations or diffusion.

Both hot and cold water pipes must be protected with a fluid category 2 device, such as a single check valve, at the point where the hose is connected to the supplying pipework.

All connection hoses should be WRAS approved.

The risk of contamination by backflow from the appliance must also be considered. Some appliances may have built in protection; these will not require an additional device to be installed. However those without inbuilt protection must have the appropriate backflow protection device installed externally according to the level of risk.

Images from the Water Regulations Guide are reproduced by kind permission of the Water Regulations Advisory Scheme (WRAS).

For a copy of the guide contact WRAS.