Backflow prevention

The seriousness of the risk of contamination by backflow is assessed using one of five fluid categories. Examples of these include:

Fluid category 5: contaminants, which are a serious health risk. Fluid containing pathogenic organisms, radioactive or very toxic substances.

Fluid category 4: contaminants with a significant health hazard. Fluid containing toxic substances including chemicals, carcinogenic substances, pesticides and environmental organisms of potential health significance.

Fluid category 1: wholesome drinking water, as supplied by Manx Utilities.

The degree of backflow risk is dependent on local circumstances. Risk assessments, if not carried out by us, should be confirmed by us.

The Byelaws require that plumbing systems, fittings and appliances are protected by suitable backflow prevention devices rated to provide protection to at least the same fluid category as indicated by the risk assessment. The Water Regulations Guide provides information on the fluid category rating of different types of backflow device.