RPZ Valve Testing & Backflow Prevention Testing
Professional testing of reduced pressure zone valves for commercial properties across the UK, using both digital and manual test methods — keeping your water system compliant and your drinking water protected.
What RPZ testing involves and why it matters
An RPZ (reduced pressure zone) valve is a backflow prevention device that protects the public water supply from contamination. Testing confirms it is still doing its job.
What RPZ testing involves
We test each reduced pressure zone valve to confirm both check valves and the relief valve are operating within the required parameters, then issue compliance documentation.
Why it matters
RPZ valves protect the public water supply from contamination. Regular testing is how you prove the protection is still working as installed.
When testing is needed
RPZ valves are generally tested annually, though the exact obligation depends on the installation, your water supplier and the relevant requirements that apply.
If a valve fails
We explain what has failed and carry out the service, repair or replacement needed, then re-test so your records show a compliant valve.
Digital & manual testing
We offer both digital and manual RPZ valve testing. Our calibrated digital test kits deliver precise, traceable readings, while manual gauge testing provides a proven, cost-effective method — we use whichever suits your site and compliance needs.
How RPZ valves prevent contamination
An RPZ valve contains two independent check valves and a relief valve positioned between them. Under normal flow, water passes through both check valves. If the supply pressure drops or reverse flow occurs, the relief valve opens to atmosphere and discharges the potentially contaminated water, preventing it from reaching the mains supply. This makes RPZ valves suitable for protecting against higher fluid categories where a simple check valve is not enough.
Two check valves in series provide primary and secondary isolation.
A relief valve opens to drain if pressure in the zone drops below mains pressure.
Discharge to atmosphere means contaminated water cannot return to the supply.
Suitable for fluid categories up to 3, and for 4 where approved installations apply.
Fluid category suitability depends on the specific installation and approval. We advise on the correct device for your risk during a site assessment.
What happens during a test
- 1
We isolate the valve and connect calibrated test equipment to the test cocks.
- 2
Both check valves are tested for tightness and correct opening pressure.
- 3
The relief valve is tested to confirm it opens at the correct differential pressure.
- 4
We record the results and explain any findings on the spot.
- 5
You receive compliant documentation for your records.
- 6
If anything fails, we quote for the service or repair needed and re-test afterwards.
Book your RPZ test
Tell us your site postcode and the number of valves to test, and we will confirm availability and pricing.