Yesterday I decided to flush my water heater and I did the following:

  1. turn to pilot
  2. turn off cold water supply to water heater
  3. open valve and drain hot water. I noticed it was still flushing for a while and I was expecting the water to be less and less every time so what I did is to turn off the water coming to the house and kept draining, and then now I noticed that the water flow was every time less and less, until it was almost no flow at all. I then closed the water heater valve.
  4. I lower the temperature of the water heater since it's already hot outside, and I was thinking in moving it back up when is winter again.
  5. I opened the water valve for the house, opened cold water valve to the water heater.

When I went upstairs and I opened my faucet with hot water I first noticed it was sputtering and brown water coming out and then the presure on the water wasn't the same as before. The next day the sputtering stopped but the pressure in some of the faucets for hot water is still not the same. At the beginning when I open the faucet it had good pressure and after 2 seconds the pressure decreased and it has been like that since then.

Note: I just checked and there are at least 5 faucets that have the same problem, not just one like I originally thought.

What could be wrong with my system?

Thank you

  • How long did you leave hot water running after flushing? Jul 30, 2019 at 16:32
  • Hello, and welcome to Home Improvement. Is this true on all of your faucets, or might it be a problem with a specific one (e.g. block aeriator)? And, you should probably take our tour so you'll know how best to participate here. Jul 30, 2019 at 18:15
  • @FredShope I left it running for like 3 minutes.
    – VaTo
    Jul 30, 2019 at 21:02
  • @DanielGriscom I don't think it would have to be with an aeriator since when I open the bathroom faucet it runs well when you just open it and then it decreases in flow after 3 seconds, and I think there's only one that has that problem. The same one that was doing a lot of very loud sputtering after I drained my water heater.
    – VaTo
    Jul 30, 2019 at 21:03
  • look for accumulated crud behind the faucet screens. heavy stuff can sink in the water, traveling down the pipe until a pinch point. When you turn on water and it runs for a few seconds, that gives time for the crud to make it up to behind your screen and reduce flow, resetting by sinking once you turn off the faucet.
    – dandavis
    Jul 30, 2019 at 21:31

2 Answers 2


maybe you didn't get the cold turned back on fully

  • I will check today when I get home but even if I did that wouldn't had to do with the water coming OUT since the cold water going into the water heater is just to fill the water heater not for water going out of it. Am I missing something?
    – VaTo
    Jul 31, 2019 at 15:27
  • @VaTo yes you are: where do you think the hot water pressure comes from? Hint - it's not the heater tank. Jul 31, 2019 at 18:38
  • got it. I will check today. It might be as easy as that (facepalm). Thank you!
    – VaTo
    Jul 31, 2019 at 19:21
  • turn on one of the outlets and then work the cold valve at-least until it stops getting stonger at the outlet. these valves that are seldom used can get stiff in places.
    – Jasen
    Aug 1, 2019 at 4:14
  • Thank you @Jasen, it was as simple as that. I didn't know honestly that the pressure was not comming from the water heater. Thank you!
    – VaTo
    Aug 5, 2019 at 23:06

You shouldn't have shut off the cold water feed. that helps nothing and may reduce the flushing efficiency. But you did, so most likely you ended up draining all hot water piping in the rest of the house. You will have to run every hot water faucet/valve individually until you've cleared all the air out of every pipe.

It wouldn't hurt to re-flush, but this time leave the cold inlet open. This might push some bubbles out of the tank itself.

BTW, there's no reason to turn off the pilot either, so long as you keep the feed open so the tank itself is always full.

  • Thank you for your response, I just think that it would be more efficient to flush all the water that is already in the water heater, avoiding new water coming in so I could know when all the water have been flushed, otherwise there's no way to know when to stop. Also I turned off the pilot so I wouldn't be wasting gas by trying to warm up water that has been flushed.
    – VaTo
    Jul 30, 2019 at 20:59
  • @VaTo Leave the pilot on but turn the heater thermostat down. As to "all the water..." what you are flushing is the particulates that have collected primarily near the bottom of the tank. a good pressure head leads to better flushing. Don't worry so much about wasting a couple cubic meters of new water. Jul 31, 2019 at 18:38

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