I just drained my water heater to flush out any sediment that may have accumulated at the bottom of the tank. When I filled it back up, I suddenly am lacking water pressure, both cold and hot, at all of the faucets of my house. What would cause this?

1 Answer 1


I assume when you drained the tank, you turned off the main cold water supply. I suspect that the cold water valve is not opened all the way now. Check to see if in fact it is open full. If it is, and the pressure is still low, you may have a jammed or damaged valve. This is very common on old valves that are not used very often. The seats and washers inside the valve can degrade over time and now are not allowing water to pass freely.

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    It turned out to be clogged aerators at all of the faucets and shower heads. I think when I flushed the tank, some of the sediment got stirred up and clogged up the faucets.
    – snicker
    Nov 20, 2011 at 17:50
  • Wow, I gotta remember that. Never seen that happen to all the fixtures at once, Nov 21, 2011 at 10:44
  • @shirlockhomes, maybe you test the first one, then fixed it (hence flashed out the system) before moving onto the next. When someone else may test them all first, and therefore block all of them. (I hate it when the testing creates the problem!)
    – Walker
    Nov 21, 2011 at 14:37
  • Usually if the main water is turned off when you drain a water heater, you don't get a lot of stuff after. I wonder if the water supply was still on a bit when the bottom drain was opened, thus mixing up the sediment with incoming water instead of draining it. I always run some water into the tank after draining, and drain it again. Nov 21, 2011 at 23:01

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