Reduced Pressure Zone (RPZ) Valves

If you have an RPZ valve installed at your premises or think you have a need to install one, there are some things you should know first.

Reduced Pressure Zone Valves, known commonly as RPZ valves or Type BA device, is a fitting used to protect against backflow in higher risk plumbing systems. Backflow has the potential to cause contamination of water, so it’s a legal requirement that the correct protection is installed within any plumbing installation.

Unlike other types of backflow protection, such as air gap arrangements used in higher risk installations, an RPZ valve is a mechanical device which requires regular testing and maintenance to ensure it continues to provide the necessary levels of protection.

Installing an RPZ Valve

The installation of any RPZ valve is notifiable under The Regulations, meaning it can’t be installed without first letting us know.

When we grant consent to the installation of an RPZ valve, our customer must agree to our Terms & Conditions of Installation and meet any conditions we impose on the proposed works.

You can notify us by completing and returning our form, which can be downloaded below. Once notified, we’ll be in touch either granting consent or requesting more information if we need to know more.

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Notification of RPZ Installation form

PDF, 74.3kB

When installing an RPZ valve, you will want to be sure you are using an installer who knows enough about them. RPZ valves can only be commissioned and tested by a suitably accredited tester, such as those listed by WaterSafe for specialist Support Services.

Maintaining an RPZ Valve

An RPZ valve is not a fit and forget solution for backflow protection. These fittings must be tested no less than once in a 12 month period in order to remain in compliance, as is a requirement under the Water Undertakers’ Approved Installation Method AIM-08-01.

As such, you’ll need to keep records of annual testing and ensure that evidence of each test is submitted to us, either by you or your nominated tester. We also keep a record of all RPZ Valves that are notified to us and monitor their testing status.

You’ll also need to think about checking the valve regularly for signs of failure and letting us know immediately if something goes wrong.

Not sure if you need an RPZ Valve?

If you’ve been advised to fit an RPZ Valve but aren’t sure if it’s needed, get in touch with us for advice. There are alternative options for providing the necessary level of backflow protection, some of which have fewer specific requirements for testing and maintenance.

You can get in touch with us by e-mailing or by calling us on 01792 841572.

If you’d like to get independent advice on RPZ Valves, Water Regs UK provides a technical advisory service and publishes industry recognised guidance on their website. You can also call them on 01495 983010 or e-mail