top of page

What Are Water Fluid Categories?

Water fluid categories are set out through The Water Supply (Water Fittings) Regulations 1999 and relate to the level of water contamination risk of stored substances. Within both commercial and domestic systems, the nature of fluids transported across a system is dependent its application. As a result, fluid categories help set out the necessary fittings and installations that need incorporating into the design to override the risk of backflow contamination into the water supply. WRAS set out five distinct categories that help to clarify the significance of the health risks and the appropriate means of meeting compliance. These categories are as so:

Fluid Category 1

Wholesome water supplied by a water undertaker and complying with the requirements of regulations made under section 67 of the Water Industry Act 1991

Fluid Category 2

Water in fluid category 1 whose aesthetic quality is impaired owing to–

(a) a change in its temperature

(b) the presence of substances or organisms causing a change in its taste, odour or appearance, including water in a hot water distribution system.

Fluid Category 3

Fluid which represents a slight health hazard because of the concentration of substances of low toxicity, including any fluid which contains–

(a) ethylene glycol, copper sulphate solution or similar chemical additives, or

(b) sodium hypochlorite (chloros and common disinfectants).

Fluid Category 4

Fluid which represents a significant health hazard because of the concentration of toxic substances, including any fluid which contains–

(a )chemical, carcinogenic substances or pesticides (including insecticides and herbicides), or

(b) environmental organisms of potential health significance.

Fluid Category 5

Fluid representing a serious health hazard because of the concentration of pathogenic organisms, radioactive or very toxic substances, including any fluid which contains–

(a) faecal material or other human waste;

(b) butchery or other animal waste; or

(c) pathogens from any other source.

With access to a variety of external and in-house training, our engineers possess all the technical knowledge when it comes to how to stop water backflow. Whether you're in need of backflow testing, a repair or a backflow preventer installation, we operate throughout the United Kingdom and actively track our responsiveness to all enquiries. Explore our backflow prevention services today to learn more about what we do!


bottom of page