My gas hot water heater is 10 years old and I replaced the temperature release valve 4 months ago since it was non functional and covered with a clear salt-like material. There is no pressure reducing valve or any kind of water softner. My hot water pressure has been reduced approximately 75 percent, cold water pressure is phenonmenal. The only thing I have done is routine maintenance which was flushing the tank for sediment. Water comes out clean. Does anyone have any clue?

OK lets flush the tank again and look at the pressure right there on the drain. How strong is that pressure. You say pressure but we need to picture this as a volume problem. Your volume is lower so when you open a faucet there appears to be less pressure, its still probably 45 psi but less gallons per minute. Is every single hot fixture affected the same? It would be rare but when you replaced your corroded T&P you may have dislodged debris which is caught in the dip tube or heat trap above the tank. We'll be getting to those if the drain has good volume/pressure.

Some heaters have hot and cold aluminum nipples supplied by manufacturer. The hot water nipple has snorkel-like device inside that allows water out, but not in. It is kind of a check valve. It may be stuck in one position disallowing water flow. I have seen it happen few times before on Rheem and American Water Heater brands. The way to check it out is to remove w/h flex line from hot water outlet, remove the nipple and inspect it for sediment and overall proper functionality of the device.

OK lets flush the tank again and look at the pressure right there on the drain. How strong is that pressure. You say pressure but we need to picture this as a volume problem. Your volume is lower so when you open a faucet there appears to be less pressure, its still probably 45 psi but less gallons per minute. Is every single hot fixture affected the same? It would be rare but when you replaced your corroded T&P you may have dislodged debris which is caught in the dip tube or heat trap above the tank. We'll be getting to those if the drain has good volume/pressure.

Water pressure is definitely reduced on all hot water outlets. This has been going on for about 3 weeks now and the hot water pressure is now reduced to a trickle. Maybe it IS time for a new hot water heater.

Some heaters have hot and cold aluminum nipples supplied by manufacturer. The hot water nipple has snorkel-like device inside that allows water out, but not in. It is kind of a check valve. It may be stuck in one position disallowing water flow. I have seen it happen few times before on Rheem and American Water Heater brands. The way to check it out is to remove w/h flex line from hot water outlet, remove the nipple and inspect it for sediment and overall proper functionality of the device.

Milo you're the second person who has mentioned the check valve. I asked a contractor buddy of mine when I heard this and he had no knowledge of this. I will look into this check valve tomorrow morning. If there is one and there is debris then that's the problem which I hope it is. Not looking forward to getting a new hot water heater. :(

khinanight: that nipple on hot water side, on your w/h is not really necessary. Most of the heaters don't have it. You can just remove it, and install new either brass of aluminum nipple.

Hello night, if you checked the drain on the water heater for pressure, and you've determened that you still have low pressure on the drain spigot then,
What type of shutoff valve do you have on the cold supply to the water heater?
Is it a gate valve type, which could be partially corroded and not opening up like it should.
If it's a ballvalve it could be stripped and not opening up, the ballvalve handle will turn to on and off position but the ball inside may be getting stuck and not opening up. Turn off the main water supply to the hose so you can inspect the valve, you will have to take the supply off the cold side that ties the valve to the water heaterso you can make a visual inspiction and see that the valve is working properly, if it's a sweat connection then you may need to replace the valve with a compression valve. You can pick one up at any hardware store. Goodluck ----zeke----

Hello night, if you checked the drain on the water heater for pressure, and youve determened that you still have low pressure on the drain spigot then,
what type of shutoff valve do you have on the cold supply to the water heater?
is it a gate valve type, which could be partialy corroded and not opening up like it should.
if its a ballvalve it could be stripped and not opening up, the ballvalve handle will turn to on and off position but the ball inside may be getting stuck and not opening up. turn off the main water supply to the hose so you can inspect the valve, you will have to take the supply off the cold side that ties the valve to the water heaterso you can make a visual inspiction and see that the valve is working properly, if its a sweat connection then you may need to replace the valve with a compression valve. you can pick one up at any hardware store. Goodluck ----zeke----

Zeke, I do have a gate valve for the shutoff and as a matter of a fact it is frozen and will not budge... thats probably the problem!

khinanight: that nipple on hot water side, on your w/h is not really necessary. Most of the heaters don't have it. You can just remove it, and install new either brass of aluminum nipple.


I will check tomorrow morning to see if there are any obstructions on the hot water side. Will also look into the shutoff valve for the cold water side. Thanks!

A gate valve can freeze up from disuse and it not necessarily th source of your problem but it could be. After checking the nipples you will have opened the system to the point that replacement with a ball valve would be a smart move.

A gate valve can freeze up from disuse and it not necessarily th source of your problem but it could be. After checking the nipples you will have opened the system to the point that replacement with a ball valve would be a smart move.

I have finally found out what the problem is. I troubleshooted the gate valve and that was working fine after I took a wrench to it. There was no obstruction to the cold water supply. As I got around to the hot side, that was where the problem was. My hot water flex line was obstructed with a hard gray-like mineral deposit. All the hardware shops were already closed so I used a 1/4 inch drill bit to temporarily remove the deposit. Lo and behold I got fantastic water pressure restored! Tomorrow Ill get a replacement hose and brass nipples. Thank you fellas for all your input. Saved me a new water heater... at least for a few more years hopefully!:D

I replaced the cold shut off and still no change in hot water volume. I removed the flex lines and checked the nipples and no obstructions. On a hunch I completely removed the flex lines and lo and behold, the hot water side was plugged with a light gray sediment like concrete. I replaced the hot water flex line and water volume was returned to normal. Has anyone ever heard of this?

Ps sorry it took so long for me to reply.

I have seen galvanized nipples enclosed on the inside with rust-like, hard, matter.

But I am glad you tackled it down yourself w/o replacing the heater ! Regards. Milo