Replacing the Main Shutoff Valve and Pressure Regulator

What each part does

The main shutoff is the valve that stops water from the service line entering the house. Older homes often have a round wheel-handle gate valve; newer installs usually use a quarter-turn ball valve that closes with a single lever movement. A shutoff you cannot close in an emergency is not doing its job.

A pressure regulator, also called a pressure reducing valve or PRV, is a bell-shaped device on the line that lowers incoming street pressure to a level the home's pipes and fixtures handle well. Not every home has one, and whether one is needed depends on the pressure arriving at your property. A plumber can measure it with a simple gauge on a hose bib.

Signs the shutoff valve needs attention

Handle will not turn, or turns without stopping the water
Water drips or weeps from the valve stem
Visible corrosion or crusty mineral build-up on the body
You have to use a wrench or excessive force to move it
It is buried, boxed in or hard to reach

Signs a pressure regulator may be failing

Pressure surges or swings noticeably throughout the day
Banging pipes when faucets close quickly
Toilets refilling on their own or faucets dripping more than usual
Pressure has suddenly dropped across the whole house
A gauge reading that differs sharply from what the regulator is set for

Gate valve versus ball valve

Gate valve (older)

Round wheel handle, many turns to close
Internal gate can stick or break after years idle
Common in original installs on older homes

Ball valve (common today)

Quarter-turn lever, quick to close
Handle position shows open or closed at a glance
Often installed during a service line replacement

Questions for your plumber

What is the incoming pressure at my house?
Do I have a pressure regulator, and is it working?
Would you replace the main shutoff with a ball valve?
Should a pressure gauge be left installed so I can check it later?
Will the shutoff be easy to reach after the work is done?

Common questions

Can I replace the main shutoff without replacing the service line?

Yes. It is a common standalone job, but the water has to be shut off upstream, which may involve the meter side. Ask the city how that is handled.

Does every Fullerton home need a pressure regulator?

It depends on the pressure arriving at the property. A plumber can test it and tell you whether a regulator is recommended.

How often should I test the main shutoff?

Gently operating it now and then helps keep it from seizing. If it feels stiff, have it checked rather than forcing it.

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