RPZ Device Service
RPZ device service covers the installation, annual testing, and repair of reduced pressure zone assemblies — the backflow preventers required for high-hazard connections like boilers with chemical treatment. FlowFast Plumbing connects you with an independent local plumber who services the check valves and relief valve, verifies passing readings, and keeps your compliance paperwork current.
- Connected with an independent local pro — never a call center queue.
- Part of our Backflow Prevention Testing & Installation services — explained up front.
Parent service
Backflow Prevention Testing & InstallationBackflow test due? What backflow preventers do, testing requirements, and how to get connected with an independent local plumber.
View all Backflow Prevention servicesA reduced pressure zone (RPZ) assembly is the heavy-duty end of backflow protection. It contains two check valves plus a relief valve between them, which opens to dump water — rather than let it flow backward — if either check fails. Utilities require RPZ devices where the hazard is serious: boilers with chemical additives, commercial dishwashers, medical connections, and any cross-connection where backflow could introduce toxins. Because the relief valve discharges to atmosphere, the device needs a drain-safe location. It can never be installed where a relief discharge would flood the building.
Through FlowFast Plumbing, an independent local plumber handles the full lifecycle of your RPZ assembly: verifying it is the correct device for your hazard, performing the annual gauge test on both checks and the relief valve, rebuilding worn internals with model-matched kits, and diagnosing the all-too-common symptom of a relief valve that will not stop discharging. The pro also makes sure the installation details are right — adequate drainage for relief discharge, freeze protection, and test-cock accessibility — and files the test report your utility requires.
Warning signs
Signs you need this service
- The relief valve discharges water continuously or in frequent bursts, which usually means a fouled check valve or debris holding the relief open.
- Your annual test shows a check valve or the relief valve out of tolerance, and the utility's notice gives you a deadline to correct it.
- You operate a boiler with chemical treatment, a commercial kitchen, or another high-hazard connection and need the RPZ protection your utility requires.
- An existing RPZ sits in a pit, below grade, or somewhere its relief discharge could flood the building — an installation defect that needs correction.
What to expect
The process, step by step
Inspection: the pro checks the installation location, relief valve drainage, and overall condition before attaching test gauges to the device.
Gauge testing: each check valve and the relief valve opening point are measured and compared against the passing criteria for your assembly.
Service: worn checks, springs, seals, or relief components are rebuilt with parts matched to the exact model, and seats are cleaned.
Verification: the pro retests the full assembly, confirms every reading passes, and files the test report with your water utility.
Prevention
How to avoid this problem
- Test annually without fail — RPZ assemblies protect against the most serious hazards, so utilities watch their compliance closely.
- Keep the relief valve discharge path clear and draining safely so a legitimate discharge never floods the area.
- Protect the device from freezing, since ice damage to the relief valve is a leading cause of continuous discharge.
Frequently asked questions
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