The purpose of a pressure relief valve in a home water supply system, like the one shown above, is to protect the pipes and plumbing fixtures from damage caused by excessive pressure. The valve is usually located along the main water line coming into the house and after the shut-off valve. They are not code-required, but definitely a good leakage-prevention safety feature. 

    However, the building code does require a pressure relief valve at your water heater to keep it from violently exploding if the thermostat fails and the water overheats. See our Frequently Asked Questions (FAQ) about Temperature and Pressure Relief Valves to learn more.

   Only a few homes have pressure relief valves on the cold water piping in our area. Because they look like a hose faucet with the handle missing, our customers will ask about it when they see one. Most are preset by the manufacturer to open if the pressure exceeds 75 psi. 

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Here’s links to a collection of some of our other blog posts about PLUMBING PIPES:

• How can I protect my pipes to keep them from bursting during a hard winter freeze in North Florida?

• Can galvanized steel pipe still be used for new water lines in a house? 

• What are the abandoned pipes sticking out of the wall in my house?  

• What are the code requirements for plumbing vent terminations?

• What are the code requirements for layout of drain piping under sinks?

• What causes a gurgling sound when a bathtub or sink drains? 

• What is a "combination waste and vent" in a plumbing system? 

• What are the pipes sticking out near my water valves?

• Are plastic pipes (PVC, CPVC, and PEX) safe for drinking water? 

• Is a hot water faucet handle required to be on the left?  

• What's that powdery crust on the pipe connections at the water heater? 

• If all the plumbing drains have water in them and you can still smell sewer gas, what's causing the problem?  

• How can I tell what type of plumbing pipe I have?

• What is the difference between water service pipe and water supply pipe? 

• What are the pipes on my roof? 

• Which water pipes are an insurance problem and possibly uninsurable?

     Visit our PLUMBING page for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles.