What should I look for when buying pressure reducing valves (prv) guide?

Test pressure with a $10 gauge. Above 80 PSI at any time means install a PRV. Set to 50-60 PSI for best balance. Always pair PRV with an expansion tank -- closed system needs thermal expansion relief.

What are common mistakes when buying pressure reducing valves (prv) guide?

Ignoring high pressure because faucets seem fine. Damage is cumulative. PRV without expansion tank causes T&P dripping. Setting too low (under 40 PSI) -- fixtures may not perform.

Pressure Reducing Valves (PRV) Guide

Buying Guide

Created by Ryan Pietrzak Illinois Licensed Plumber · In the plumbing industry since 2009

Updated February 20, 2026

Key Takeaway

Municipal pressure can exceed 100 PSI -- too high for residential plumbing. Anything above 80 PSI damages pipes, fittings, appliances, and water heaters. A PRV on the main line reduces pressure to a safe 50-60 PSI. Required by code when incoming pressure exceeds 80 PSI.

Overview

What to Know

How PRVs Work

Spring-loaded diaphragm restricts flow to maintain set outlet pressure. Adjusting screw: clockwise increases, counterclockwise decreases output pressure.

When You Need One

Incoming pressure above 80 PSI. Signs: dripping T&P valve, water hammer, premature aerator failure, supply line leaks. Test with a $10 gauge on any hose bib.

Replacement

PRVs last 7-12 years. Failing symptoms: pressure fluctuations, returning water hammer. Not field-repairable -- replace the whole unit. Install an expansion tank at the same time.

Buying Tips

Test pressure with a $10 gauge. Above 80 PSI at any time means install a PRV.
Set to 50-60 PSI for best balance.
Always pair PRV with an expansion tank -- closed system needs thermal expansion relief.
Check output pressure annually.

Common Mistakes

Ignoring high pressure because faucets seem fine. Damage is cumulative.
PRV without expansion tank causes T&P dripping.
Setting too low (under 40 PSI) -- fixtures may not perform.
Trying to repair instead of replacing ($30-75 for new valve).

Bottom Line

Test pressure. Install PRV if above 80 PSI. Set 50-60 PSI. Pair with expansion tank. Replace every 7-12 years.