What a pressure-reducing valve does

Water systems deliver enough pressure to serve the highest homes in a zone, which can mean more pressure than plumbing fixtures are designed for at a house lower on the hill. A pressure-reducing valve, often called a PRV, sits on the main line just after the shutoff and steps the pressure down to a household level. Highlands Ranch has plenty of rolling terrain, and many homes have one.

Like any valve with springs and diaphragms, a PRV wears out. When it fails, pressure in the house creeps up toward street pressure. Nothing dramatic happens at first. Then washing machine hoses, toilet connectors and ice maker lines start failing more often, faucets drip, and the water heater relief valve may begin to discharge.

Signs pressure may be too high

  • Banging pipes when a washer or dishwasher valve closes
  • Toilets refilling with a loud hiss, or fill valves wearing out quickly
  • Faucets and shower valves that drip despite new cartridges
  • Water dripping from the water heater relief valve discharge tube
  • Several hose or connector failures within a short time
  • Sprinkler heads misting heavily instead of spraying

Checking your pressure

A screw-on gauge from a hardware store gives a quick reading.

  1. Find a test point.Use a hose bib, a laundry faucet or the water heater drain valve.
  2. Read with nothing running.Make sure no fixtures, irrigation or appliances are using water, then attach the gauge and open the valve.
  3. Watch for a few minutes.A reading that climbs over time with nothing running can indicate a failing PRV or thermal expansion.
  4. Compare with guidance.Ask a plumber what range suits your fixtures and water heater; many plumbers aim for a moderate household range.
Thermal expansion tank
A small tank near the water heater that absorbs pressure as water heats; needed on many closed systems with a PRV
Relief valve
The safety valve on the water heater; a dripping one is a symptom, not something to plug
Main shutoff
Usually right before the PRV; know where it is
Water hammer arrestors
Small devices at washer and dishwasher valves that soften pressure spikes

Common questions

Who owns the pressure regulator, me or the water district?
A PRV inside the house on your side of the meter is typically the owner's responsibility. Ask your water and sanitation district if you are unsure where their equipment ends.
Will the restoration contractor check my pressure?
Some do note it, but diagnosing and replacing a PRV is plumbing work. If a burst hose caused your loss, ask the plumber to test pressure before reconnecting new hoses.

General information for Highlands Ranch, not a quote or professional advice. In an emergency, call 911.