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Why the relief valve at the water heater is leaking, and what to do about it

By In Expansion Tanks, leaking relief valve On January 22, 2012


Leaking T&P relief valveWhen a temperature and pressure  (T&P) relief valve at a water heater leaks, it’s usually a simple fix; just replace the valve.   These valves cost less than $15, and replacing the valve is a very basic job – just drain some water out of the water heater, remove the discharge tube, and replace the valve.  No big deal.

Unless it starts leaking again.

If a recently replaced T&P relief valve starts leaking again, it probably means that the relief valve is only doing it’s job; it relieving excess pressure in the water heater.  When this happens, the fix gets a little bit more involved.  I’ll explain.

When a water heater heats up the water in the tank, the water expands.  When this happens, the water typically ends up expanding back out the cold water inlet, all the way back to the water supply coming in to the house.  The municipal water supply for the house acts as a gigantic expansion tank… and nobody notices.  This is illustrated in the diagram below.

Natural expansion

What would happen if a one-way valve, or check valve, was installed on the water supply piping for the house?  The water wouldn’t have anywhere to go.  As the water heater heats the water, it expands, which builds up pressure in what is now essentially a closed system.  When the pressure builds up enough, the T&P relief valve on the water heater just does it’s job and relieves the excess pressure by leaking a little water.

Pressure regulator prevents expansion

In Minnesota it’s rare for a check valve to be installed on the water supply line for the house, but it’s fairly common to have a pressure regulator installed.  When the pressure from the water supply coming in to a house is too high, a pressure regulator needs to be installed on the water main, to prevent damage to the plumbing components in the house.  The problem that these regulators can create is that they will act as a check valve; they’ll allow water in to the home, but they won’t allow water back out.  This creates what is called a ‘closed system’.

When this happens, the T&P relief valve for the water heater can leak.  This doesn’t happen every time a pressure reducing valve is installed, but there may be other problems that show up in the house, such as the toilet fill valves randomly re-filling toilets, or faucets chronically dripping.

The Fix  When a closed system exists on the water distribution piping in a home, an expansion tank needs to be installed somewhere on the plumbing system.  This is a fairly simple and straightforward fix; an expansion tank will give the water somewhere to go when it expands, and the T&P relief valve on the water heater will stop causing problems.

Expansion tank installed

This rule also applies to hot water heating systems; when a boiler heats the water in a hydronic heating system, the expansion tank allows for the water to expand without the pressure relief valve leaking.  If the pressure relief valve on a boiler system chronically leaks, even after replacement, it probably means there is a problem with the expansion tank.

5/20/14: For troubleshooting steps, click here: http://www.structuretech1.com/2014/05/troubleshooting-a-leaking-temperature-and-pressure-relief-valve/

Reuben Saltzman, Structure Tech Home Inspections – Email – Maple Grove Home Inspector

        


About the Author

Reuben

Reuben is a second generation home inspector with a passion for his work. He grew up remodeling homes and learning about carpentry since he was old enough to hold a hammer. Reuben has worked for Structure Tech since it was purchased by Neil in 1997, and is now co-owner of the company. Reuben’s favorite customers are the ones who have a lot of questions; he grew up thinking he was going to be a school teacher because he enjoyed teaching others so much. In a sense, that’s a lot of what home inspections are about, so Reuben truly does what he loves. Reuben has an A.A. degree in liberal arts and has attended most of the Building Inspection Technology classes at North Hennepin Community College. Reuben and his wife are the proud parents of two young childen, Cy Alexander and Lucy Nicole, and have a German Shepherd named Stanley. With two young children Reuben doesn’t have much free time, but he still tries to play disc golf as often as possible during the summer. Reuben lives in Maple Grove, MN. Professional Qualifications / Memberships: *ASHI Certified Inspector *President, ASHI Heartland Chapter *Member, Minnesota Society of Housing Inspectors (MSHI) *Licensed Minneapolis Truth-in-Sale of Housing Evaluator *Licensed Saint Paul Truth-in-Sale of Housing Evaluator *Licensed Maplewood Truth-in-Sale of Housing Evaluator *Licensed Hopkins Truth-in-Housing Evaluator *Licensed Robbinsdale Point of Sale Evaluator *Affiliate Member, Southern Twin Cities Association of Realtors

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245 Comments

  • Ahsan 12 MONTHS AGO

    @Lenny, there is currently no expansion tank installed. It was never there before as well. We do have one for home heating (furnace).

  • Lenny 12 MONTHS AGO

    Ahsan, You do not have an expansion tank or it is not working properly.

  • Ahsan 12 MONTHS AGO

    Hi Jordan, I retested the pressure reducing valve....actually it does increase / reduce the water flow pressure (water coming out of the tap) but the water pressure gauge will still hit 160 PSI regardless of the pressure valve setting. So I am assuming that the pressure reducing valve is working however it is still a mystery why there is this higher downstream system pressure (under no flow condition).

    • Reuben Saltzman 12 MONTHS AGO

      @Ahsan - at this point, I think you would do well to have a plumber check it out.

  • Jordan 12 MONTHS AGO

    A couple of questions: if you're water heater has with check valves on the hot and cold nipples leading into the water heater and out of it, how can the pressure tank help with water expanding out of the tank? Also, I noticed that your illustration shows the expansion tank before the hot water heater shutoff valve...most of the illustrations seem to stress it should be between the shutoff valve and the cold water nipple. Does it make a difference? Thanks.

    • Reuben Saltzman 12 MONTHS AGO

      @Jordan - I've never seen a water heater with check valves on the hot and cold water nipples, but yes, a check valve on the cold side would render an expansion tank useless. Also, the shutoff valve for the water heater should be located immediately before the water heater. Where have you seen illustrations showing otherwise?

  • Ahsan 12 MONTHS AGO

    Tried to reduce the pressure via water pressure reduction valve, but it did not reduced the PSI which is still showing at 160. Could it be that the valve is not functional and need to be replaced ?

    • Reuben Saltzman 12 MONTHS AGO

      @Ahsan - I think that's exactly what your issue is. Probably a defective pressure reducing valve.

  • Paul DE 12 MONTHS AGO

    I put a RainBird pressure gauge I bought at HomeDepot on my washing machine's cold supply and my pressure reached 160psi after about an hour of not using water. Yikes! Normal pressure was about 58psi. I checked the Schrader valve on the expansion tank and it sprayed water. So, it looks like my expansion tank's bladder was blown. Without the expansion tank my relief valve was doing what it should at 155psi. Releasing pressure. The instructions for the new tank said it has a bladder instead of a diaphragm which allows it to be installed at any angle. It's an Amtrol st-5. Online reviews said the cheaper in-store ones fail much more. I installed the new one with 58psi of air pressure and so far my water pressure has been steady at 58psi. My mistake during troubleshooting was not realizing that any water usage will equalize the pressure again. The only time the water pressure would have reached a dangerous 155psi or greater in my situation was after a lot of hot water usage followed by no water usage at all. That's when the most water is heated and the most expansion occurs without any release. Thanks for sparking the thought process for me!

    • Reuben Saltzman 12 MONTHS AGO

      @Paul DE - thank you for taking the time to come back and post your results here. I'm glad to hear you got it figured out.

  • Ahsan 12 MONTHS AGO

    You are right....the pressure is at almost 160PSI. So how can we reduce this to the desired level.

  • Ahsan 12 MONTHS AGO

    Sounds very logical. Any advice on how to check the pressure in the system ? I have meter installed to Furnace which shows reading of approx 25PSI. I am not sure if this will be the same for Water Heater as well. Thanks a lot for your help !

    • Reuben Saltzman 12 MONTHS AGO

      Put a device like this on the hot water connection for your washing machine. http://www.homedepot.com/p/Watts-3-4-in-Plastic-Water-Pressure-Test-Gauge-DP-IWTG/100175467#

  • Ahsan 12 MONTHS AGO

    Thanks for the reply. You were right. I installed a wrong valve. This morning I installed a correct one and unfortunately the water is still leaking. Not sure what should I do now. Thanks for your help!

    • Reuben Saltzman 12 MONTHS AGO

      @Ahsan - if it's still leaking and the correct valve is installed, there are three possibilities: 1) The valve is defective. 2) The pressure in your tank is over 150 psi. 3) The temperature of the water in your tank is over 210 degrees Fahrenheit. If it were me, I'd be checking the pressure in my system.

  • Ahsan 12 MONTHS AGO

    Many thanks for such a nice information which I am sure have helped many across the world. Following advices and recommendations, I have replaced the TPR valve to stop the almost constant dripping water. The water has unfortunately not stopped dripping. It ONLY stops dripping when there is hot water being used at home. This is my 6th year in the home. There is no expansion tank installed and some how things were working fine until now. Any recommendations from your side will be highly appreciated.

    • Reuben Saltzman 12 MONTHS AGO

      @Ahsan - if it still leaks, I'm guessing the wrong valve was installed. Make sure the valve is set to go off at 150 psi.

  • Paul DE 12 MONTHS AGO

    Thanks so much for the information! I replaced my heater with the exact same model and size as the original about 8 months ago and everything has been fine until now. My relief valve that came on the new one has been driving me nuts for a couple weeks now. It has been so intermittent I actually had to put a plastic cup under the pipe to make sure that is actually where it was coming from. It is. I can dry everything up and watch it for about 8 hours, through people taking showers, and doing dishes. Everything will be dry. Then, randomly, there will be an inch of water in the pan. I haven't been able to find a pattern. I think the relief valve is bad, but I need to ask a question. There is an expansion tank installed in the cold water inlet line that sits above the pipe. That means that the air section would be above water section. When I drained the water heater the expansion tank drained too. I didn't do anything special to refill the expansion tank. I just hooked everything back up and turned on the water. Was I supposed to prefill the expansion tank, deflate it, or anything? Instructions for new ones said just pressurize and connect it. I never deflated the bladder pressure on this one. I just left it as it was. Could an air bubble be stuck above the water in the expansion tank causing it not to work right? Also, the outside temp is dropping around here. The inlet water would be colder but the tank itself is under the stairs in the warmer house. Thanks for any help!

    • Reuben Saltzman 12 MONTHS AGO

      @Paul DE - I'm no expert at troubleshooting expansion tanks; I know just enough to explain the concept. Your theory sounds plausible. I'd check the pressure on the water distribution piping in the house, then compare it to the pressure in the expansion tank. If they're not the same, get that corrected. That should be your first step.

  • Andy McDonnell 12 MONTHS AGO

    So I changed Pressure relief valve on water heater but had strange problem. After turning off cold water input and draining about 15 gallons, the relief valve still flowed water when opened. I drained 15 more gallons, opened a HW faucet, and bled all pressure by holding relief valve open. Two minutes later I removed the old valve and warm water kept gushing out, until I was able to thread new relief valve into place, soaking me and dumping a few gallons of warm water onto the floor. MY question is, where did that water come from? Back flow from the hw piping? It was warm, not cold, and high in the tank.

  • Tara 12 MONTHS AGO

    Thank you so much! Happy Holidays!

  • Tara Herbert 12 MONTHS AGO

    Dear Mr Saltzman, Your blog is so great. I too have a question. My tpv started leaking.....initially a big flow of very hot water. I think it was my fault as I noticed the boiler pressure was low and let in more pressure. Then I left the boiler running on high and went out for a couple of hours. When I got back I heard the water rushing out through the Tundish and through the relief pipe to outside. I checked the boiler and saw the pressure was up to 3 bar. So I drained some water through a radiator to get the pressure back down to 1.5 bar. However water continued to come though the tpv for the next 8 or 9 hours ...less over time. I turned off the boiler and switched off the power into the tank. Eventually the water went to a drip and now it's stopped. I need To go away for a few days over Christmas and the plumber is coming straight when I get back. I will leave the boiler and power off as its not freezing weather. My big question is shall I switch off the mains water or not? There is no cut off for water directly into the tank I can work out so its mains or nothing. Just frightened to do the wrong thing. THanks so much.

    • Reuben Saltzman 12 MONTHS AGO

      Hi Tara, once you have added water to the system, the fill valve should be shut back off, and you shouldn't have to worry about more water coming in. It doesn't sound like you have an automatic fill valve, so you should be safe leaving the water on. Without seeing your system I obviously can't guarantee that, but that's my best guess. If there is a valve that adds water to your boiler system, it should be turned off.

  • L 12 MONTHS AGO

    the water dept was completing a repair and apparently some debris made its way to our PRV valve and we had significantly reduced water pressure. We are waiting on a plumber to fix it but in the mean time I wondered if using the little water pressure we have to shower will damage our hot water heater? Thanks!

  • Brandon Baker 1 YEAR AGO

    expansion tank was what i ment in the last post

    • Reuben Saltzman 1 YEAR AGO

      @Brandon - yes, this could be a bad valve, a bad tank, or the tank might not be charged. Read through the previous comments to see what I mean about the expansion tank not being charged. The tank has a bladder that separates the air from water; if the bladder fails, the expansion tank has failed. That's not too likely on a three-year-old system. If the pressure in your expansion tank matches the water pressure, replace your relief valve.

  • Brandon Baker 1 YEAR AGO

    Hey Mr.Saltzman looked all over the web for a blog like this and im hoping you will be able to help me i have a pressure regulator coming in on the main water supply and an expansion tank before the hot water heater...today after two showers i was in my basement (having a smoke) and i hear alot of water running i look and the pressure relief valve is discharging all over...filled the pan by the time i got it to stop and all over the floor (atleast 3 gallons) could this just mean that the valve is going bad? or the expansion tank? and what causes the tank to go bad? its a new home and was installed no later then 3yrs ago..any help would be appreciated

  • Tim 1 YEAR AGO

    Rueben, I recently bought a house and the water heater wasnt giving me much hot water, about enough for a 5 minute shower. I called the home warranty and they came out and flshed the system and got out a lot of sediment. He mentioned that they cannot replace it until it actually is leaking. A few hours after he left I noticed that the T&P was leaking quite a lot, about the same amount that comes out of a bathroom sink when turned on. Do you know why this would happen and how I can fix this? The water heater is very old and does need to be replaced but I was hoping to hold off a little while Thank you for your help

    • Reuben Saltzman 1 YEAR AGO

      @Tim - I'm guessing the T&P valve was operated, which could cause an old defective valve to start leaking.

  • Scott Simpson 1 YEAR AGO

    For the first time in 10 years I opened the release valve on my water heater. I have never had an issue, a leak or any issue with it prior. Now the copper drain tube from the release valve will not quit leaking water. Does that mean my valve is defective and will not close now that I opened it.

    • Reuben Saltzman 1 YEAR AGO

      @Scott S - yes, that's a common occurrence when someone tests one of those valves that hasn't been operated for a long time. Time for a new valve.

  • James 1 YEAR AGO

    T&P valve has a constant flow coming out. I've turned down the temperature on the water heater, adjusted the house's water pressure to 60psi, installed an expansion tank and adjust it to 58psi, and replaced the pressure relieve valve, yet it continues to leak. Anything else I can try?

    • Reuben Saltzman 1 YEAR AGO

      @James - if the house pressure is at 60 psi and water constantly comes out, it means the valve is open, the valve is defective, or the wrong valve is installed. Make sure the valve is set for 150 psi and 210 degrees (f).

  • Bob 1 YEAR AGO

    My T&P valve was leaking. I checked the water pressure coming into house and it was 100 psi. Between the cold water shut-off and the water heater, I installed a Pressure Reducing Valve, a pressure gauge and an expansion tank. The reducing valve and the tank were set at 50 psi and the gauge confirmed that. The leaking stopped for one month and started again. I noticed the gauge sometimes reads 80 or 90 psi and sometimes 50 psi. I closed the cold water inlet valve and the gauge went to 0 psi. I left it closed for 1 hour and then checked the gauge and it read 75 psi. So, I seem to be getting a backflow from the hot water line that has high pressure and causes the leaky T&P. How do I fix this problem?

    • Reuben Saltzman 1 YEAR AGO

      @Bob - I'm no expert at troubleshooting situations like yours, but my best guess is that you either have a defective or improperly installed expansion tank. You'll have to talk with a plumber for more info.

  • Sarah Tooke 1 YEAR AGO

    My husband replaced the relief valve and thermostat on the hot water heater, and it's fine for awhile then the relief valve starts leaking water and there is a lot of steam coming from it. What can we do to fix this?

    • Reuben Saltzman 1 YEAR AGO

      @Sarah T - It sounds like you have a defective water heater. What is the temperature of the water when this happens?

  • scott 1 YEAR AGO

    So i need to recharge the expansion tank to match hot water heater pressure its an older expansion tank so I don't have the manual is there a common procedure for this. Also is that the reason I don't have the water pressure in the shower as before with the new heater.

  • scott 1 YEAR AGO

    Replaced hot water heater due to old one leaking out bottom. Now the new hot water heater leaks water outof the pressure valve. I have an expansion tank already. The old hot water heater never leaked. What do you think is the problem. I tried turning the temperature down. And that didn't help

    • Reuben Saltzman 1 YEAR AGO

      @Scott - you probably need to charge the pressure tank. See my comment to "Biniam" on 7/2/13.

  • Chad 1 YEAR AGO

    Ive actually noticed that it only leaks whenever she takes a bath and the tank starts to fill back up

  • Chad 1 YEAR AGO

    my relief valve keeps leaking after replacement. ive never had this problem before. my wife said she had seen standing water out by our incoming line. i have yet to see the standing water come up but my question is If there is a blockage or something in the main line would that cause my relief valve to leak?

    • Reuben Saltzman 1 YEAR AGO

      @Chad - no, I'm sure there's no blockage in your main water line that could cause the relief valve to leak.

  • Kevin 1 YEAR AGO

    Reuben, I tested my T&P valve tonight as the directions called for annually (just bought the house last month and not sure when it was last tested) and it has been dripping for a few hours now since I tested it. It did not drip before I tested it, now I'm regretting doing it. I turned off the the water supply to stop the dripping over night. We where also out of town for the past week, not sure if there is excess pressure from not using the hot water for that long or if the valve just needs to be replaced? Do I need to hire a plumber to do that?

    • Reuben Saltzman 1 YEAR AGO

      Kevin - the valve needs replacement. You can find youtube videos of how to replace the valve; that might help you decide whether you need a plumber.

  • Paul 1 YEAR AGO

    After a remodel I noticed that a pipe is now welded to the heater relief valve and it appears to feed plumbing for a bathroom. I tried it see if the valve would activate and pushed fairly hard but can't budge it. I've never tested one before so I'm afraid to pull the lever too hard. This appears to be a dangerous adaptation. I live in nevada. Is this a valid setup that meets code?

    • Reuben Saltzman 1 YEAR AGO

      Hi Paul, That sounds like an unsafe setup. I'm not familiar with Nevada plumbing code, but whatever it is, I'm sure your setup doesn't meet it. Get a plumber to fix it.

  • Carol H. 1 YEAR AGO

    Glad I found your site! Hopefully you can help me, I'm trying to save replacing my water heater as a very last resort. A couple of months ago, our gas water heater started leaking from the top. We drained it completely and then refilled it. No problems until today. Today, when my husband started getting ready for work, we discovered there was no hot water. Went downstairs to find water on the floor, minor compared to the first a few months before. I opened the PRV to let some of the water out, let it go for about a half an hour and then closed it again. It is making a sound kind of like a hiss, if that makes any sense. So, I turned off the level on the pipe above the water heater, as my husband told me to do. The leak and the hissing sound both stopped instantly. I will be checking it around noon my time (it is 9:41 in the morning right now) to see if the water is heating up. I live in Colorado, and we have had a lot of rain over the last week (I'm sure you all have seen the news about it). While we were not hit by any flooding, I mention this in the event it might be related. I appreciate any info you can give. Thank you so much for this blog!

    • Reuben Saltzman 1 YEAR AGO

      Hi Carol, It sounds like you probably need a new water heater.

  • Mike Widmer 1 YEAR AGO

    Must of been Saturday night sometime, while I was at work. My wife came down the basement Sunday morning to feed the dog, when walking over by the dog food, almost half of the basement was water. 1) did the water come from the pressure relief valve. 2) is the tank leaking somewhere? Now, today is Monday, I am sitting in the basement, typing you this, ran all our showers for 10 minutes, and so far, nothing is happening. What should I do? Mike W

    • Reuben Saltzman 1 YEAR AGO

      Hi Mike, Stick your finger up inside the T&P discharge tube. If it's wet, there's your culprit. If not, I don't know what it was.

  • evee sue 1 YEAR AGO

    I live in a condo, the water heater is enclosed in a closet with a pan . My water heater leaked, (about >10 years old), and the plumber adviced me to replace it with new one, but he said he need to upgrade it, he said the new plumbing code requirement is to have the discharge pipe extended to the outside of my unit. he will use approx. 30 feet pipe. Is this a new plumbing code?

    • Reuben Saltzman 1 YEAR AGO

      @evee sue - there is no requirement in Minnesota for the T&P discharge tube to discharge to the exterior of the home. The Minnesota State Plumbing Code says "The discharge pipe shall be full size and run to within 18 inches of the floor or a safe place of disposal." If you're outside of Minnesota, you'll need to check your state plumbing code.

  • Donna 1 YEAR AGO

    Reuben, replaced the T&P relief valve and viola, works like a champ. Thanks for your help!

  • Donna 1 YEAR AGO

    Hello. We just installed a new Whirlpool Gas hot water heater. Filled tank with water and then PRV begin leaking/spewing to the point we had to shut it off at the cold water supply valve off. That stopped it. But it was too late to go back to the store. Could the PRV be defected on new water heater? We did go down in size from a 50 gallon to 40 gallon short. Thanks in advance for your expertise!

    • Reuben Saltzman 1 YEAR AGO

      Hi Donna, yes, it's possible that your water heater came with a defective T&P relief valve. It's even more likely that it's stuck in the open position.

  • Val 1 YEAR AGO

    Thank you for this site. We just replaced a 19 year old water heater that dripped just a bit from the relief valve. We have since reduced the pressure in our home to 45psi (from about 100) so we were surprised to find that the new heater is dripping more than the old. Not only is it dripping but it seems like during the day when we're at work it "throws up" water because there is much more water on the floor than a drip should cause. We'll be replacing the Pressure Relief Valve in hopes that is all we have to do. Fingers crossed!

  • JayMar 1 YEAR AGO

    I have a 6 year old Lochinvar 50-gal gas water heater (model no: LTN050G-4) that is not producing hot water and there is water filling up in the drain pan as I don't ever recall water being in there before. The relief valve discharge line has a steady drip of water into the pan which has filled the pan to almost full. There's no corrosion anywhere and the PRV looks normal. What steps should I take to resolve the steady drip of water into the pan from the PRV discharge line before reigniting the pilot light? And is it safe to reignite the pilot light if water is dripping from the PRV discharge line?

    • Reuben Saltzman 1 YEAR AGO

      @JayMar - replace the T&P relief valve. Yes, it's safe to re-ignite the pilot even if the T&P relieve valve is leaking.

  • Eugene 1 YEAR AGO

    Reuben, thanks for the prompt reply. There are no additional leaks since replacing the drain valve. Would draining the water heater again (done once in 11 years) help with the thermostat sediment issue? Or, would you recommend replacing a thermostat in a 1998 model? During the repair, I did vacuum off the burner. It had a lot of black sediment piled on top of it…

    • Reuben Saltzman 1 YEAR AGO

      Draining the water heater now probably won't make any difference; it needs to be done regularly from the start. I would just plan to replace the water heater soon; water heater are expected to last for about 10 - 15 years.

  • Eugene 1 YEAR AGO

    I hope I am not asking a question previously ask. I recently replaced the drain valve on my gas water heater. Prior to the replacement, I operated the heater on A for several years and moved it between A and B about one year ago. Since replacing the valve, I have to operate the heater on B to satisfy my family. We have been in the home for 11 years and prior to replacing the valve I performed zero preventive maintenance (I did not know it was required). I drained the water heater during valve replacement and also learned from the manual TODAY my water heater requires annually the temperature pressure relief value be manually open. Does the requirement to increase the setting indicate an issue, will opening the pressure valve help? Thanks in advance.

    • Reuben Saltzman 1 YEAR AGO

      Hi Eugene, You're probably having to turn up the temperature dial because the thermostat is covered in sediment; this happens over time. Testing the pressure relief valve won't affect that.

  • Donnie 1 YEAR AGO

    I have a 40 gal Hot Water Tank and the T/P valve is leaking after replacing it a year ago, I tried turning off the cold water at the inlet, but it continued to leak. My next step was to turn the water back on and turn the thermostats (both) all the way down to 90 deg. I left it that way for a day and checked the water temperature to insure that the thermostats are working properly. They appear to be just fine: nothing but warm water! The T/P valve was still leaking however. I also checked the pressure at an outside faucet and found it reading about 75 pounds. With the T/P Valve leaking continually however, I am thinking that it may be defective, or it could be excessive pressure at 75 pounds. If the problem is the incoming pressure, what are my options? An expansion tank will just fill up with water due to pressure and the t/p valve will start leaking again once the expansion tank reaches capacity, right? Replacing the T/P valve won't remedy the pressure problem either will it? HELP!!!

    • Reuben Saltzman 1 YEAR AGO

      Hi Donnie, Before doing anything, I would try replacing the T&P valve again. An expansion tank will not fill up with water; it has a bladder that allows air to compress inside it. If the valve leaks again after replacing it, contact a good plumber.

  • Carol 1 YEAR AGO

    Our six year old Whirlpool Gas Water Heater has decided to stop working. The pilot light will not light. We have an Expansion Tank and have noticed that on the pipe leading to it there is a build up of rust. Also the top of the Water Heater has a spot where it looks like it is rusting and has a hole. I can see rust stains as if the pipe was leaking but never actually saw it leak. So my question is is it time for a new heater? Is there something that needs to be replaced?

  • jeanne 1 YEAR AGO

    If we had a discharge about [a gallon], then the discharge stopped, do we still have to replace the pressure relief valve? Thank you so much

  • Dave 1 YEAR AGO

    The pressure relief valve on my gas hot water heater was dripping water on a system that has an expansion tank which I thought may be waterlogged. I turned off the water main, drained part of the system, and attempted to add air to the expansion tank. However, after adding air, I am not getting a pressure reading at the Schrader valve. Is this an indication that my expansion tank is defective and needs replaced?

    • Reuben Saltzman 1 YEAR AGO

      Dave - air is supposed to be added to the expansion tank when water is already in the system. If it won't take pressure after that, yes, it's probably defective.

  • Steve 1 YEAR AGO

    Hi Reuben, We had found a small amount of water nearby our gas water heater every three/four days for two weeks now. Our plumber just replaced the T&P valve last week. We could not find any leaking from the water tank. Is it possible that the water came underneath the concrete floor? Thank you for your time. Steve

  • Marco 1 YEAR AGO

    Is it necessary to have a drainage line coming out from your t&p relief valve? Mine is located on the top of my water heater, and there is no drainage line attached to it. No water is leaking from the t&p valve though. My concern is will my house be flooded if the t&p valve does release water?

    • Reuben Saltzman 1 YEAR AGO

      Marco - yes, there should be a discharge tube attached. You can read more about it here: http://www.structuretech1.com/2010/05/water-heater-installation-defects/ The T&P valve typically won't release water suddenly; it's usually more of a slow leak.

  • Shawn Macedo 1 YEAR AGO

    Thanks for the great information on your blog. This article was just what I was looking for!

  • Reuben Saltzman 1 YEAR AGO

    Dave - your expansion tank should have a small valve on it called a Schrader valve. You can use a bicycle pump to re-charge the pressure tank to make sure the pressure inside it matches the pressure of the water in your home. To check the pressure of the water in your home, you need a pressure gauge. If the pressure in the tank doesn’t match the pressure of the water, the expansion tank won’t work properly. For more detailed info on this, you should locate the installation instructions for your specific expansion tank and follow the manufacturers instructions.

  • Dave 1 YEAR AGO

    The pressure relief valve on my gas hot water heater is dripping. The system also has an expansion tank which I think may be waterlogged. Is there a way to add air to the expansion tank? If so, how do I add air to the system and how much should be added? The expansion tank specs list Air Pre-Charge as 20 PSI, Max Air Charge as 80 PSI, and Max Working (Water) as 150 PSI. Thanks for your assistance

  • Dave 1 YEAR AGO

    The pressure relief valve on my gas hot water heater is dripping. The system also has an expansion tank which I think may be waterlogged. Is there a way to add air to the expansion tank? If so, how do I add air to the system and how much should be added? The expansion tank specs list Air Pre-Charge as 20 PSI, Max Air Charge as 80 PSI, and Max Working (Water) as 150 PSI. Thank you for your assistance.

  • Scott 1 YEAR AGO

    YEP! bad section of 3/4" copper pipe...had a pinhole leak. Had to cut out a section of drywall about half the size of a doorway, cut and replaced the pipe, and now all good. Just need to let dry and get a drywaller in to finish the job. Good blog and great info here!

  • Scott 1 YEAR AGO

    I have an 11 year old house with gas water heater (75 gal). I have copper plumbing in the house. I noticed the last week or two a sound of "rushing water through pipes" that could be heard from inside the house on the wall where the water heater resides in the garage. The wall is also warm to the touch where the water heater is (warm on the garage side wall and house side wall). I noticed quite a bit of water under the water heater as well. I shut off the water supply to the house, drained the water tank, turned the water back on, continued to drain (looked clear, no sediment..on city water for house good quality). I tested the T&P relief valve and it seems to be operating correctly. When in the middle position, water runs freely from the valve. With the water to the house on, and water to the water heater shut off, I still get the sound of rushing water. When the house water supply is shut off, the sound stops. Any ideas of what to do next? I never notived this sound or the felt heat on the wall in my 11+ years of living here.

    • Reuben Saltzman 1 YEAR AGO

      Scott - It sounds like you have a leak that probably isn't related to the water heater. Check your water meter to see if there is water flowing when it shouldn't be. If so, you have a leak somewhere, probably in the wall.

  • biniam 1 YEAR AGO

    I meant valve not calves on the previous post,my smart phone is not so smart sometimes.