A friend of ours writes that the water company dug up their road and installed a new larger supply pipe in his street. They also installed a Check Valve to reduce Back Flow. Now his Water Heater Pressure Valve is leaking and he is wondering what he should do.
The first thing to understand is when water is heated in your water heater it expands. This expansion can be dangerous and they can actually explode so manufacturers install a pressure relief valve so hopefully in a over heating situation the water heater will vent enough pressure to reduce the chance of explosion. If your water heater did explode it probably wouldn’t take out your whole house but remember many of these heaters run off of natural gas and if it was to cause a problem with the gas line you could be in trouble.
So, our friend believes that the increased line the water company installed is the direct culpret for his problems. The first thing you should do if this happens is check the temperature of your hot water. Is it very hot or scalding hot? If it is then you probably have a bad thermostat which is overheating the water. If the water is normal temperature then the next thing to do is turn the electricity and if necessary the gas off to the water heater and let it cool down. This can take a long time but you could grab a shower to speed it up some. Now just leave the water heater off over night or through out the day and see if the pressure valve continues to leak. If it does it could either be a bad valve or over pressure from the street.
How to cure High Pressure water from the Street Valve
If you have high pressure water running thorough out your home it can cause problems such as over pressure in your water heater but it can also cause problems at every appliance and fixture and valve.
To find out if you have high pressure you can call a plumber or purchase a water system pressure tester.
Pressure Testers are normally attached to the hose bib on the outside of your home. Normally they are actually attached with an extension pipe that replaces the hose bib. This is because the outside hose bib where you attach your garden hose is one of the largest connections to your system and if there is a leak or problem you will see it outside. When new houses are built plumbers leave them installed for a few days to check that there is no problems they will also shut off the street valve before your meter to see if there are any leaks in your internal pipes. If the pressure drops to zero overnight you may have a leak in a wall or some place that is not normally visible and a repair must be made.
In our home owners case they should first make sure that the water heater is not overheating and if that is not the problem then they can check the street pressure.
If the street pressure is high then a pressure restrictor valve can be placed where the water from the street enters the house and before the water meter.
Now normally this cost would be something the home owner needs to eat but because the water company did just do work they may be held to do the work or reimburse you. It is difficult to say what their agreement is but normally all work after the outside service cutoff valve that is probably in the street in front of your house is where their responsibility ends.
I would put them on notice though because if it does damage your water heater or other fixtures and appliances they may need to cover it if the pressure is well above normal range.
Final Note
When in doubt and you have a pressure relief valve leaking or going off on your water heater first go to your electrical panel and turn the power off to the water heater. Do not approach it until it cools down. The gas can also be shut off but the water heater should have a shut off when power is not available and shut the gas off at the water heater. If you can you should also shut off the gas at the valve that supplies the water heater.
Once it is cool you can perform your inspections. Your manufacturer should have a Service Manual that you can use to test the system and all of its parts. Some parts must be powered while testing and others do not require power to be tested. you will need a good quality volt meter that can read house voltage and ohms.
Finally if you have concerns then call a plumber. Water heaters are not normally dangerous but they can be so if you don’t feel you are mechanically inclined then call someone and keep the heater shut off until they get there.. there will be no rush once the heater is turned off but your showers will be cold.