I did a water heater flush by turning off my heat down to the pilot light only and setting it to pilot instead of on, let it sit overnight. I then opened the stock drain valve and let it drain until it was just trickling a tiny bit. The trickling went on for hours it seems and didn’t stop after approximately two hours that I waited. Almost no sediment came out except for a small 4mm chunk. This doesn’t seem right for a water heater that hasn’t been flushed in about 7 or 8 years if not 9 years when it was first installed. Does a slow trickle plus very little sediment mean there is a big chunk that won’t come out? It was flushing at a really fast rate for a while, to where the hose was being almost fully utilized. I stuck a wire up the drain valve after removing the twist part, but it didn’t cause any more sediment to come out, and it didn’t feel like there was anything blocking it.

The pic shows the sediment after it broke apart when I picked it up. Picture of sediment

  • Gas or electric water heater? Do you know what the mineral content of your water supply is? Are you on well or city water? You may have had more sediment come out than you saw, it may have been very fine and suspended. After you drained, did you flush? That is, run water in for 30 second drain, repeat several times— attempting to stir up anything on the bottom.
    – Tyson
    Commented May 14, 2018 at 23:01
  • Quite often, the sediment becomes like oatmeal (packed tightly) and almost none will actually come out in a flush. I have an electric water heater and have to scoop out the sediment through the lower heating element opening.
    – mike65535
    Commented May 14, 2018 at 23:09
  • @Tyson gas. I did flush some cold water and it still didn’t change the output. At the beginning and at the end I was using a bucket so I should have been able to detect something I would think. It was quite clear except for a little bit of black particles that kind of looked like rubber shavings maybe from a rubbber washer, and there was not much of it at all. I only flushed twice afterwards though. I think my water is pretty hard because my dishwasher sometimes leaves horrible white spots on my dishes even after cleaning the filter.
    – James C
    Commented May 15, 2018 at 14:11
  • @mike65535 Interesting. Did you have to remove the heating element for access then? I assume it’s sitting on the bottom instead of floating?
    – James C
    Commented May 15, 2018 at 14:14
  • Yes, I had to pull the heating element. It's about 6 inches above the bottom of the tank. I used a shop vac with a garden hose taped to the vac's nozzle as a sort of anteater snout to suck out the "oatmeal".
    – mike65535
    Commented May 15, 2018 at 14:16

2 Answers 2


In addition to the answers above, I have backflushed mine by hooking up a washing machine hose (double female) and turning the water on and off. I am on a well and I have a good filter system, so I rarely have much-unsuspended junk in my water. Home Depot has a scope (Ryobi?) that allows you to look into the water tank through the lower element hole. It has many uses, like you can do your own colonoscopy! Lol!


What works well: leave supply on, leave gas on ( turn electric off) , connect hose to drain , open drain valve. I doubt that closing the supply and draining does much of anything. I also add a on/off ball valve to the drain hose and cycle it several times at several second intervals. The inlet line should go to the bottom of the tank, the inlet flow will dislodge debris on the bottom. Flushing the tank will have no significant effect on hard water.

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