In Plain English
Quick Answer
A valve that reduces high water pressure from the street to a safe level for the building's pipes and fixtures.
Definition
Definition
A valve that automatically reduces and stabilizes the incoming water pressure from the utility supply to a safe operating level for building plumbing systems. Most codes require a pressure reducing valve (PRV) when street pressure exceeds 80 PSI. PRVs protect fixtures, water heaters, and appliances from damage caused by high pressure.
Context
Why It Matters in Bidding
When street pressure exceeds the code threshold, a pressure reducing valve becomes a required scope item, and forgetting it on the plumbing takeoff leaves a gap the bid will have to absorb later. Beyond the valve itself, high incoming pressure can trigger expansion-tank and relief requirements that add cost, so reading the civil pressure data drives an accurate sub price. Mis-sizing the device risks fixture damage and warranty callbacks that erode margin.
Example
Example
Seeing the utility report list 95 PSI at the meter, the plumbing estimator carries a pressure reducing valve and a thermal expansion tank in the takeoff so the bid reflects the code-required components rather than a callback after rough-in.
See Also
Related Terms
FAQ
Questions Contractors Ask
When does code require a pressure regulator?
Most plumbing codes require a pressure reducing valve where the static water supply pressure exceeds 80 PSI, reducing it to a safe level at the fixtures. Estimators should check the utility's available pressure during takeoff, because a high reading turns the PRV—and often a related expansion tank—into required scope rather than an optional add.
Does a pressure regulator require a thermal expansion tank?
Often yes. A PRV can create a closed system, so when water heats and expands it has nowhere to go, raising pressure dangerously. Codes typically require a thermal expansion tank or device in that case. Estimators should pair the two in the takeoff to keep the bid compliant and avoid a later change order.
Who installs the pressure regulator on a project?
The plumbing subcontractor typically furnishes and installs the PRV as part of the domestic water service, usually near the meter or where the supply enters the building. Estimators should confirm the valve, its sizing, and any required expansion tank are within the plumbing sub's scope so the device is not missed at buyout.
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