Backflow protection: FAQs

What is the backflow risk categorisation for a hose union tap supplying watering systems?

The backflow risks associated with hose union taps supplying watering systems will vary dependent upon their use (intended or otherwise) and the environment in which they are sited. Ultimately it is for the local water undertaker to determine whether fluid category 5 backflow protection is required.

Factors taken into account when assessing those supplying watering or irrigation systems included but are not limited to:

• The use of chemical additives. For example, fertilisers, herbicides, and insecticides.

• The irrigation system design. For example, pop-up sprinkler heads, seep hoses.

• How the system is installed. For example, what parts of the system are below ground or permanently fixed above ground.

• The size of the system and the environment in which it is installed.

The installation of an irrigation system must be notified, conditions are likely to apply

To avoid the risk of cross connection with other supplies irrigation system pipework should be clearly marked in accordance with BS 1710.

Hose union taps are typically categorised as a fluid category 3 or 5 risk. Below are some examples of backflow prevention which may be used where the hose union tap is categorised as either a fluid category 3 or 5 risk.

Fluid category 3 backflow protection arrangement

Fluid category 5 backflow protection arrangement