What you need to know about backflow preventers

Backflow is bad news and, in the unfortunate event it occurs, it poses a health risk. It leads to undesirable, non-potable water streams returning to the usable water supply. Backflow occurs if there is a change in pressure, causing the liquid to move in the wrong direction. In a situation where your premises handles many different liquids, gases, or other possible contaminants, it’s important to ensure nothing crosses over. Due to this, backflow preventer inspections should be a top priority for your water systems. These inspections are simple for professional plumbers and ensure you keep people safe.

In 2001, the Colour Water Regulations Guide was published, detailing how UK companies could actively enforce these regulations. The Fluid Category identifies the level of contamination risk. Category 3 presents a slight health risk, Category 4 a significant health risk, and Category 5 a serious health risk. For each level of risk, you need to make sure you have a suitable backflow prevention device. It also needs to be maintained effectively, depending on risk category.

How often should you get your backflow preventer inspected?

It is always useful to check with the manufacturer or stockist of your backflow preventer to find out their recommendations for maintenance. However, For RPZ valves, the UK Water Regulations Advisory Scheme (WRAS) supply an ‘Approved Installation Method’ which requires you to check the Reduced Pressure Zone (RPZ) at least once a year – more frequently if specified by the suppliers.

You need to rebuild it completely every five years. You also need to test the Double Check Valve (DCV) once every three years. These checks aren’t frequent enough to impede your operations which is always good news. So there is little excuse to avoid them. Be aware: it is your responsibility to make sure your backflow preventer is in proper working condition at all times.


According to the Approved Installation Method document, any competent person can install RPZs, but they must be tested and commissioned by a Water Industry Approved RPZ Tester. But it is good to be extra careful with your backflow prevention.

Any ‘competent person’ does not mean just any person can install the device. It is always best to contact a professional plumber to take care of matters that could pose a risk to public health when not installed correctly. This will ensure you don’t run into any problems later on.

If you’re in need of commercial plumbers to take care of your backflow prevention, get in touch with Higgins today on 01625 613 308. We are Water Industry Approved plumbers with years of experience, so we know we can help.