If your taps hammer when they close, your toilet fill valves keep failing, or your water heater’s relief valve drips, the cause may be up the street, not in the house. Municipal pressure on hillside lots can run well above the 40–60 psi a home’s plumbing is designed for, and a pressure-reducing valve is what stands in between.
What A PRV Does
It sits on the main line where water enters the house and holds the downstream pressure at a set value regardless of what the street delivers. It is a mechanical spring-and-diaphragm device, and like anything mechanical it wears.
Where They Matter Most
Hillside neighbourhoods where the municipality has to push water uphill: Mission, Westwood Plateau and Burke Mountain in Coquitlam, White Rock, Silver Valley in Maple Ridge, and parts of Abbotsford and Chilliwack. Homes at the bottom of a pressure zone can see 100 psi or more at the meter.
Signs Yours Is Failing
- Pressure that creeps up: banging pipes, dripping relief valves on the water heater, fixtures and supply lines failing early
- Pressure that drops off: weak showers throughout the house that were fine last year
- Pressure that changes through the day
- The valve itself weeping at the stem
A gauge on an outside tap, read with everything off and again with a fixture running, tells the story in a minute.
Why It Is Worth Fixing
High pressure quietly shortens the life of everything downstream: braided supply lines, dishwasher and washing machine hoses, toilet fill valves, cartridges and the water heater. A burst washing machine hose at 100 psi empties a lot of water into a house very quickly.
Replacement
A PRV is normally replaced rather than rebuilt, set to the pressure the house needs, and paired with a thermal expansion tank on the water heater, because once the PRV closes the system off from the street, heated water has nowhere to expand. In BC that expansion tank is required, and it is often the part that was never installed.
Related: low water pressure explained · thermal expansion tanks · plumber in Mission
Related guides
- Well And Septic Basics For Rural Fraser Valley Homes
- 7 Signs You Need a Plumber in Langley BC
- Poly-B Pipe Replacement Cost in BC — What Langley Homeowners Need to Know
- Emergency Plumber Langley BC — What to Do When a Pipe Bursts
