Why Is My Relief Valve Still Leaking?
A leaking pressure relief valve can be scary.
It can also be confusing.
That is true when the water pressure looks normal.
This issue happened at a Florida mobile home park.
The outside pressure relief valve started dripping years after moving in.
The valve was located after the main shutoff.
The homeowner replaced the valve.
It still leaked.
So, the valve was capped.
That may seem like a quick fix.
But capping a relief valve can be unsafe.
A relief valve is there to protect the plumbing system.
It lets water escape when pressure gets too high.
Later, a pressure gauge was added to an outside spigot.
The gauge showed about 60 PSI.
That sounds normal for many homes.
But the red needle later showed a spike near 100 PSI.
That means pressure had climbed too high at some point.
The park management had no clear answer.
So, a pressure-reducing valve was installed.
The pressure then stayed near 60 PSI.
But the gauge still showed high-pressure spikes.
The relief valve also leaked fast.
Next, the homeowner found there was no expansion tank.
An expansion tank was installed.
After that, the gauge stayed near 60 PSI.
That seemed like the fix.
But the 75 PSI relief valve still leaked.
It did not just drip.
It leaked like a small stream.
Question
Why does my 75 PSI relief valve still leak after adding a regulator and expansion tank?
Answer
The relief valve is likely seeing pressure above 75 PSI, or the valve setup is wrong. Do not cap it. Check the pressure reducing valve, expansion tank charge, valve location, and gauge reading. A licensed plumber should inspect it if water keeps flowing.
What May Be Causing The Leak?
The pressure-reducing valve may be installed backward.
It may also have dirt stuck inside.
A bad regulator can allow pressure creep.
Pressure creep means pressure rises after water stops moving.
The expansion tank may also be set incorrectly.
The air charge should match the house water pressure.
This should be checked with the water pressure off.
The relief valve may also be in the wrong place.
If it sits before the regulator, it sees park pressure.
That pressure may still spike above 75 PSI.
The relief valve may also be rated too low.
Many systems use higher-rated valves in the right location.
But the right rating depends on the plumbing setup.
You can learn more about pressure-reducing valves from Watts.
You can also review expansion tank basics from The Home Depot.
What Should Be Checked Next?
- Check the pressure before and after the regulator.
- Confirm that the regulator arrow faces the water flow.
- Test pressure overnight with a good gauge.
- Set the expansion tank charge to match 60 PSI.
- Make sure the relief valve is not before the regulator.
- Ask the park for the highest supply pressure reading.
A steady leak means the problem is not solved.
The valve is warning you.
It should not be ignored.
It should never be capped again.
High water pressure can damage pipes, fixtures, and water heaters.
A plumber can test the system in the right order.
That is the safest next step.
I’m Chris Mayer, writing for Plumbing 101.
