# Low hot water pressure



## Oldman

How's the pressure in the tub (Not the shower)?


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## Mike Swearingen

Usually, the hot water pressure is fairly equal to the cold water pressure going into the heater.
Has someone partially closed the water heater cold water supply valve? If it's wide open, the valve may be clogged with mineral buildup or debris. You can turn OFF the main water supply and dismantle the valve to check it.
And when is the last time that you flushed the tank?
Good luck!
Mike


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## crebive

I last flushed my water heater when I noticed the problem. The tub is the same as all the other faucets when on, it is low, when two faucets are on, very low.

I will look at the valve, hopefully that will be the only problem. How long do water heaters last? I hear they have a "mind" of their own and can last 2 years or 20.

D


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## Oldman

Sounds to me as if the valve has broke inside and is not opening fully (Had that happen before!) May need to replace the cut off valve to the water heater, on some gate valves you may could repair it.


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## redline

When you flush the water heater do you get good pressure from the hot water drain?

You may have sediment in the hot water tank or the sediment may be clogged in the line coming from the hot water tank.


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## Teetorbilt

The valve failing is a good one (sort of). I'm not a plumber and haven't seen one go bad in 30 yrs. BUT I've had 3 in the last 6 mos. Maybe the Chinese brass can't take our water.


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## Oldman

Teetorbilt, If they flushed the water heater I'd say they had to cut off the cold water into the tank, this would cause the seat to bottom out, but if the screw broke off it would not allow the washer to lift fully off the seat. If the cold water pressure is good the hot should also be good. Heck, it may be that it is a gate valve which requires many turns to fully open it.


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## MAS2006

*Water heater*

10 year avg on water heater before problems start, (leaking, etc.) Elects have a sacrifical rod in them. How hard is your water? Do you have 1/2 or 3/4 to and from heater and how far to sink or tub. 3/4 line will give better multi use preformance. Check faucet screen they display hard water build up first (around here clean once a year with out softner in system)


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## MAS2006

*Flushing*

 What did you get out when you flushed it? What type of pipe do you have? Should be copper if only 12 yrs old.


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## crebive

haven't responded in a couple of days...sorry.

I tried the valve, but upon taking apart it seemed that the valve is one piece? I took the handle off, then a copper nut, but after that there was nothing more to take off. I had a threaded end sticking out of the valve body, with white plastic on the inside. The threaded end was where the handle is connected to and if the handle where on it, it would turn to open or close the valve. The plastic was solid and I didn't want to force anything. So anyway I put it all back together. I have copper pipe. 

Funny, I consider myself a pretty handy guy. I completely gutted my master bath and put in new tile, new counters, new floor. Same for my other two bathrooms. Replaced my Kitchen floor, even finished my basement. But when it comes to plumbing I get intimidated to try anything. Water can cause so much damage, and I would hate to meddle with something and wake up in the morning only to find my basement flooded, because I failed to tighten a nut or something.

crazy....maybe time to call a plumber.

Thanks for all the advice
D


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## redline

Sounds like you have a ball valve.

Where is the next spot that you are able to turn and get hot water just after the hot water tank? Do you have a washing machine before any of the hot water faucets in the bathrooms or kitchens?


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## crebive

I do have a washing machine that would be the closest hot water valve

Okay so I drained my water heater again, and I got more green stuff and the water was a bit discolored. But still I have little pressure. 

When I drain my hot water heater and i open the valve to drain it all the way open, should I get a pretty good water force out of that drain valve. the main water is off so there is no water coming into the house. When i was draining the water heater the water was running rather slow. My tank is 50 Gallons and it took FOREVER to drain.

Also, since I have copper pipe thru out the house, my problem should be either a valve to my water heater or my water heater itself, correct?

I just want to get to the bottom of this. My Heater is 12 years old, so maybe it is breaking down? My water in the house is still hot, just low pressure.

Our water is hard water too. we always get water stains on our shower doors etc. need to use CLR alot.

any other ideas or just suggestions, anything will help!
Thanks!
D


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## redline

crebive said:


> I do have a washing machine that would be the closest hot water valve
> 
> 
> Leave the main water supply on and disconnect the hose on the hot side going to the washing machine. See if the pressure drops at this point or if it is as high as the the pressure at the main coming into the house. If the pressure drops then the problem is from that point back to the hot water heater.
> 
> 
> Okay so I drained my water heater again, and I got more green stuff and the water was a bit discolored. But still I have little pressure.
> 
> Leave the main water supply on when you drain the hot water tank. Does the pressure drop when you are draining the tank? If so then the problem is from the tank back to the main. It could be sediment in the bottom of the tank. You have hard water and the tank is 12 years old so it may be that the tank is near the end of its life.
> 
> If the pressure doesn't drop then the problem is as the water leaves the hot water tank or further down the line. The outlet from the hot water tank could be filled with sediment or corrosion. Do you have a di-electric fitting connection as the pipes leave the hot water tank?
> 
> When I drain my hot water heater and i open the valve to drain it all the way open, should I get a pretty good water force out of that drain valve. the main water is off so there is no water coming into the house. When i was draining the water heater the water was running rather slow. My tank is 50 Gallons and it took FOREVER to drain.
> 
> 
> The water will drain slow if the main is turned off because there is not any pressure pushing the water out of the tank just gravity. If you drain the tank with the main water off then you have to open the relief valve near the top of the tank to allow air into the tank. You could also open a faucet to let air into the tank. Just be sure that you turn on the hot side of the faucet. If the relief valve is old then it may not close fully when you try to refill the tank.
> 
> Also, since I have copper pipe thru out the house, my problem should be either a valve to my water heater or my water heater itself, correct?
> If you have copper thru out the house then that helps. Do you have copper coming into the house from the main? Do you know if the main line coming from the street is copper?
> 
> 
> I just want to get to the bottom of this. My Heater is 12 years old, so maybe it is breaking down? My water in the house is still hot, just low pressure.
> 
> Do you have a coupling at the top of the water heater where the cold water comes in?
> Or is it a solder joint?
> 
> Do you have a coupling connecting to the hot water coming out of the top of the tank?
> 
> If you have couplings for both the cold water coming in and the hot water coming out then I would disconnect the hot water pipe coming out fo the hot water heater and see if you have any blockage (sediment/corrosion) trapped in the pipe. If you have good pressure coiming into the hot water tank but you have a drop in the pressure as it leaves the tank then the problem is at the tank. If the pressure going into the tank is the same pressure that is coming out if the tank (at the drain and also at the first connection near the top of the tank then the problem is down further in the pipe. Process of elimination.
> 
> 
> Our water is hard water too. we always get water stains on our shower doors etc. need to use CLR alot.
> Are you on a public water supply or are you on a well?
> 
> 
> any other ideas or just suggestions, anything will help!
> Thanks!
> D



Try these and see what happens.


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## crebive

Wow thanks for the detailed answers. When i leave the water to the tank on my pressure is good out of the drain valve. I'm not sure how to check for the water coming out of the water heater. I do know that the hot water to the washing machine is just as low as the rest of the house, as it takes forever for the machine to fill when we wash clothes in just hot water. So it sounds like it is the water heater? correct? 
But let's say that the problem is farther down the line and I have a clog in the pipe somewhere and that pipe is located behind a wall, how would you fix that? Plus how would you determine where the clog is? I imageine there is lots of pipe behind the walls. Plus since I have copper pipe isn't that supposed to "resist" clogging?

Thanks again!
D


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## MAS2006

You can check pressure/flow at washing machine. Turn Hot/cold off, cycle washer, start fill should relieve pressure. Remove hot from back of machine, (carefully most are plastic parts) inspect if screen clogged most washers have them. Put hose in washer tub, hold while you turn just hot back on, see how your pressure and flow are. If low, your back to heater outlet. Most well systems have lime/calcium build up. Older city water can have rust problems. On electrics build up coats heating elements and can become quite hard and thick. Chalk or rust color is the usual, is your green copper statue patina or alge green? Flushing a water heater gets neglected until it complains.


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## rdooba

*Same issue- what was your fix?*

Redline- I have the identical problem described in this post with low hot water pressure (http://www.diychatroom.com/f7/low-hot-water-pressure-2364/) and I did the same things that you did (drained the hotwater heater several times, changed the valve on the hot water spigot in the bathroom- none worked and the low hotwater pressure is all over the house). Did you ever get it resolved?? What ended up being the cause of the problem and the eventual fix? I REALLY appreciate your sharing your experience, many thanks!


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## kenmac

Look for rstriction on the cold water inlet to the w.h. If you have low hot water perssure throughout the house ( if you dont have galvvanized pipes) Low cold water inlet to the w .h would result is low hot water .. Mabe scale build up as the hot water leaves the tank


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## rdooba

Thanks for the tips. The problem, in my mind, cannot possibly reside in the cold water feed because the cold water pressure in the hous is 2 to 3 times as strong as the hot water (ie: normal/no noticable difference). I've done many of the things listed in this post and none have worked. I beleive that the issue may reside either in the hotwater heater itself (which i did drain to no avail) or in the hot water pipe exiting the heater. Either way, the issue is the same as Redline's original post so I am wondering what he eventually did to fix it. 

It not, do you have any other suggestions for me?

Thanks!


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## kenmac

cold water feeds the w.h . Hot water is forced out the top & out of the w.h by the cold water entering at the top of the w.h.Could possibly be even the dip tube in the cold water inlet of the w.h..


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## kyball

*Sounds crazy but it worked*

I tried the flush method on my water heater and it didnt fix the problem. However when I started to fill it back up I noticed that the water going into the heater seemed to be not flowing properly. I figured that there must be some sort of blockage before or at the cold water entrance to the heater. I took a wrench and hit the water pipes in the general area where the cold water entered the tank and wala! it dislodged whatever was keeping the water from flowing properly. Problem fixed!


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## Viper16

Well since it sounds like it is a newer water heater...i don't think ti could be it. 

What is the water like? is it hard water? do the faucets have any sort of corrosion or buildup on them? I wonder if there could be some restriction due to hard water...like a buildup. Could be a pain in the butt to do, but get a pipe nipple and connect the supply line to the line to the fixtures and see if it does it then. If so it is the water heater...if not, then something is plugged up. 

Take a look at the ball valve...can you semi close it and look in there...see if the ball has become cracked...if it is a plastic ball.


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## biggles

your anrod is restricted that the hot water exits up and into the copper line to start the run of hot water pipes..OR the copper fitting closest to the HOT OUT on the top of the heater is closing down like an artery with a cloresterol build up in a blood vessel...if it slowly has becoome less and less over the year it is that mineral build up on the copper fitting that is threaded into the steel female hot tank out


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## lakhan124

I had the same problem so I did two things - drain the hot water from the drain water but I think it didn't work. Then I lifter the pressure relief value from the top of the water and I could see hot water coming out at very high pressure. That assured me there is no problem with my heater. I did it couple of times and *it worked.*


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## spark plug

crebive said:


> I last flushed my water heater when I noticed the problem. The tub is the same as all the other faucets when on, it is low, when two faucets are on, very low.
> 
> I will look at the valve, hopefully that will be the only problem. How long do water heaters last? I hear they have a "mind" of their own and can last 2 years or 20.
> 
> D


I haven't heard of either. (2 or 20). On average, they last 10-12 years. I had one last 8 years. The next one lasted EXACTLY Ten Years. Just as long as the (pro-rated) Warranty! (No matter what) :furious::no::drinkon't Drink and Drive, Ever!!!


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## Snell Lancaster

I also had clogged pipes from hard water. First, I cleaned the screens in each faucet outlet and shower and clothes washer. Then I turned off the elec., took out the heating elements (lower), shined a light into the water heater and found a few inches of crap minerals. I took the shop vac, put a smaller half inch hose on the end of the fitting and ran it around inside the tank (after draining). After cleaning, it seemed to work fine. Hot water with no clogs. Now I have a tankless. Wish I had a tank again. No elec. $ saved. Goes off while showering. Is very temperamental. Mind of its own.


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## spark plug

Snell Lancaster said:


> I also had clogged pipes from hard water. First, I cleaned the screens in each faucet outlet and shower and clothes washer. Then I turned off the elec., took out the heating elements (lower), shined a light into the water heater and found a few inches of crap minerals. I took the shop vac, put a smaller half inch hose on the end of the fitting and ran it around inside the tank (after draining). After cleaning, it seemed to work fine. Hot water with no clogs. Now I have a tankless. Wish I had a tank again. No elec. $ saved. Goes off while showering. Is very temperamental. Mind of its own.


You should (as a long term solution) use Chemical water softeners. Or use the services of a "Water maintenance" co. Who will gladly (for a hefty fee) service your water supply on a Monthly basis, or as needed! (No matter what) Don't Drink and Drive, Ever!!!:no:!


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## paulahenry1

*low hot water pressure cold is fine*

*Instructions*


*Things You'll Need:*


One dime.
 
http://ad.doubleclick.net/click;h=v...p://clk.atdmt.com/IWC/go/273386824/direct/01/

1
 
Go to your water heater and turn off the cold-water supply that runs to the tank. This will generally be a valve located directly above the tank, or somewhere near it, on the cold-water line. You can tell which line is cold by touching it.

2
Go to the lowest faucet in the house that is not having the water-pressure problem, ideally a basement faucet. Turn the hot water on full and let it run.
3
Locate the faucet that's having the problem. Close the drain (so the rubber washer can't fall down it when you take the aerator off). Remove the aerator screen at the end of the faucet by turning it clockwise. Once it's off, make sure to keep holding it in the same upright position as it was on the faucet, so the washer doesn't fall out.
4
Press the dime into the aerator, flat side down against the screen, to completely close it off. Depending on the design, you may have to remove the washer, put the dime under it, and put the washer back in over it. In most faucets, the dime will fit perfectly. Now replace the aerator on the faucet, turning it counter-clockwise.
5
Slowly turn on the cold water tap until it's fully on, and leave it on. Water will not come out of the faucet (because the dime is blocking it), so the water will run back through the hot-water line.
6
Return to the faucet in step 2 and watch the water coming out; you will likely see discoloration and waste material in the water stream. Let it run for a few minutes, until the water runs clear again. Let it continue running while you go back to the faucet with the dime in it. Turn off the faucet, remove the dime, and replace the aerator. Then turn off the basement tap and turn back on the water line to the water heater.

*Tips & Warnings*



Do not turn off the basement hot-water tap until after you've gone back and turned off the tap with the dime in it.

I han very low hot water pressure in all faucets, but the cold was fine. Flushed my hot water heater and it got worse, so I did this and now have great water pressure at all faucets. Was very easy and only took about fifteen minutes!!!!
​


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## efowler

*easy fix*

Had this problem after flushing my water heater and it was an easy fix. Check the Dielectric Union, which joins the hot water outlet from the tank to the copper pipe. Mine looked like a clogged artery from a heart attach victim ... probably 98 percent restricted. Pull the old one, sweat a new one on and I was done for $4. 

They look like this:

http://www.zorotools.com/g/00059328/k-G2993094?utm_source=google_shopping&utm_medium=cpc&utm_campaign=Google_Shopping_Feed&kw={keyword}&gclid=CMPoit2Grq4CFcrQKgod3UJ0Rw


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## jaydevries

ohh no not another low pressure scenario:laughing::thumbup:


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## efowler

That's what I said when I found this fix on another site. 

Should've been more detailed in my instructions. Turn off the feed to the water heater and drain some room off the top of the tank through the flush valve. You'll need to open faucets to get it to drain. If you don't, once you crack that union the water from the pipes above the tank will be all over you and the floor.

Pull pipe off the top of the union and you can look and see if it's clogged.


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## Sandmangs

*Hot water pressure problem*

I have similar issues with my hot water pressure. My house is only 8 years old, I have two 50 gallon water heaters in the attic daisy chained for the house. The symptom is when opening any faucet in the house, it starts off strong then instantly goes down 3/4. if you open multiple faucets, it will trickle or not even flow at all.

I have copper pipes throughout the house, and the problem happened suddenly. I called a plumber and at first he said he hadn't seen that issue before (strong then instantly trickle), but he came back and said his boss sees it all the time, that there is sediment in the tanks, and they need to be replaced. I seriously question the replace part. After reading the thread, I will try to flush the tanks this weekend, but wanted to post here with the added symptom of starting strong then a trickle within a second or two. 

Could it be sediment in the tanks that clog the screen when the flow starts? Would a flush help in this case?

Thanks for any help you can provide!


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## Homerepairguy

Sandmangs said:


> I have similar issues with my hot water pressure. My house is only 8 years old, I have two 50 gallon water heaters in the attic daisy chained for the house. The symptom is when opening any faucet in the house, it starts off strong then instantly goes down 3/4. if you open multiple faucets, it will trickle or not even flow at all.
> 
> I have copper pipes throughout the house, and the problem happened suddenly. I called a plumber and at first he said he hadn't seen that issue before (strong then instantly trickle), but he came back and said his boss sees it all the time, that there is sediment in the tanks, and they need to be replaced. I seriously question the replace part. After reading the thread, I will try to flush the tanks this weekend, but wanted to post here with the added symptom of starting strong then a trickle within a second or two.
> 
> Could it be sediment in the tanks that clog the screen when the flow starts? Would a flush help in this case?


Sandmangs,

When you say "when opening any faucet in the house", I assume you mean any "hot" water faucet in the house since your thread is titled "Low hot water pressure".

That being the case and with the symptoms of strong flow and then instantly going down, the problem sounds like a bad heat trap valve on your water heater. The heat trap could be partially clogged with sediment. There's a ball in the heat trap and when it moves off it's seat, to allow water flow, the sediment could be forming another seat on the other end, blocking water flow.

There are heat traps for the hot and cold water lines and either could be bad but the hot one is more suspect since sediment from the heater exits past the hot heat trap.










The heat traps shown are external and can be replaced. There can be heat traps internal to some water heaters but I don't know if they can be replaced.

There may be a way to unclog a heat trap on the hot outlet without doing any plumbing work. If you want to try it, let me know. I've never tried it myself but I think it might work if the clog is fresh.

HRG


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## Sandmangs

Thank you for your thoughtful reply, homerepairguy, I really appreciate it. I will look tonight to see if they are external and try replacing the hot heat trap if external. I'll let you know what I find out. 

Thanks again!


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## Homerepairguy

Sandmangs said:


> Thank you for your thoughtful reply, homerepairguy, I really appreciate it. I will look tonight to see if they are external and try replacing the hot heat trap if external. I'll let you know what I find out.
> 
> Thanks again!


Welcome. BTW, not all water heaters have heat trap valves.
If yours does and you find that an external one is clogged/defective, since plumbing work has to be done anyway, maybe consider tossing the heat trap valves and building heat trap piping instead.









See 16th article down at:
http://waterheatertimer.org/9-ways-to-save-with-water-heater.html

Heat trap piping won't ever get clogged by sediment and are almost effective as heat trap valves. Do a google image search on "water heater heat traps" to see different ways to do this.

HRG


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## zhangar

i had the same problem,and i just fixed my self.
Replace Both (((((((heat trap nipples))))))) cold and hot

picture 
http://cfnewsads.thomasnet.com/images/large/457/457271.jpg


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## Alan

efowler said:


> Had this problem after flushing my water heater and it was an easy fix. Check the Dielectric Union, which joins the hot water outlet from the tank to the copper pipe. Mine looked like a clogged artery from a heart attach victim ... probably 98 percent restricted. Pull the old one, sweat a new one on and I was done for $4.
> 
> They look like this:
> 
> http://www.zorotools.com/g/00059328/k-G2993094?utm_source=google_shopping&utm_medium=cpc&utm_campaign=Google_Shopping_Feed&kw={keyword}&gclid=CMPoit2Grq4CFcrQKgod3UJ0Rw


Why dig up a 3 year old thread??? :huh:

http://t3.gstatic.com/images?q=tbn:...646EjeRlezFv_K5kgawucNvG_L0OZCDtKp5TlPsTpea0Q


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## switchoff

I know this post is super old but I just wanted to add my 2 cents to anyone googling this problem. I had the same experience as Kyball. I drained the tank and that didn't solve the problem, actually the water was pretty clean.

I turned off the cold water supply and turned on a hot water faucet. I took a wrench and banged the inlet and outlet pipes right above the tank. When I turned the water supply back on I could hear the hot water sputtering and then gushing out! Problem solved. 

BTW it is a John Wood tank I have.


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## GeeBee

I had the same issue with low hot water pressure when cold side was fine. A plumber fixing a different problem advised me (wrongly!) that it was my pressure regulator. Replaced that Saturday - no help at all. Sunday I bypassed the water heater with a flex coupler and water came out of the hot faucets, showers etc no problem. So on checking the inlet side to the water heater I discover the little ball in the valve in there is stuck. The stem on it was wedged against the side, so I was getting about 1/4 normal flow. For now I have NO check vale there. Is that a bad idea? At least I now get to have a shower that isn't a pathetic trickle.


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