It's been a few years since I flushed my water heater and I recently went to do it and it's only dripping slowly, not running and flushing. Possibly related, in the last few months we've been running out of hot water much sooner - no change in usage, but now we regularly run out if even two people shower at once.

I had somebody out and they told me everything is fine and that he'd tested it and everything was good (though he was here less than 10 minutes). When I mentioned the failed flushing, he said sediment gets big if you want to long and you just need to get a new heater, and then just told me to take shorter showers and had no other help to offer.

My questions:

  • Would a lot of sediment cause us to run out of water sooner - like it's harder to heat new water to keep up?
  • How can I flush sediment if it won't drain and trying to use a wire hanger to break it up doesn't do anything?
  • It's 12 years old - is it just worth replacing at this point anyway?
  • I have a 47 year old heater here it's still working.
    – Jasen
    Commented Feb 15, 2020 at 4:59
  • Electric water heater? Commented Feb 15, 2020 at 14:42
  • @nosparksplease yes, it's electric. Our water is pretty hard as well, so I assume sediment would build up pretty quickly.
    – SqlRyan
    Commented Feb 16, 2020 at 21:41

3 Answers 3


I'm assuming it's a heat-exchanger type high pressure water heater

If you remove the electrode you can put a hose in and siphon out the water

If you then remove the heating element there'll be a larger hole near the bottom you can poke a digging tool, or water blaster into

You may find that the lower heating element has failed and your system is only using the upper element, that would explain a reduction in the amount of available hot water.


One thing to try to get the sediment stirred up and moving out would be:

Turn off the heat supply (caution, mostly)

Shut off the cold water supply to the heater. Open a hot water faucet, or more than one. Remove the aerator screens - crud may come out here.

Attach a hose to the drain and to a cold hose bib. Open the drain, and open the hose bib. Allow water to flow from the hot faucet for a while, then shut off the cold hose bib and remove the hose from the bib and route it to a drain/sump.

The idea, which may or may not work depending how firmly clogged your heater is, is to backflush and loosen the sediment with the water coming in from the drain before trying to drain it out the drain.


12 years is a bit toward the short life cycle, but if you have more money than time, talent, or patience then replacement is not out of the question. If you have to call a plumber to replace elements then your cost per year of limited added life might justify just replacing the tank.

Short supply usually means the lower element isn't functioning, but it could be the dip tube has failed.

In an typical two element electric water heater the lower element only gets power when the upper thermostat senses the top of the tank has reached set point. The failure could be the upper stat or lower stat, but most often is the lower element. That is the cheap first step, a new element is usually about $15 for the element and $10 for the tool to remove it. As long as I have the tank drained I've been known to change both elements. You would need to disconnect power, backflush, and drain before removing the element. While the lower element is out it would be good to use a 3' piece of tubing or garden hose attached to a shop vac through the element hole to clean out sediment. (Have patience, and work at it.)

The dip tube is normally only a problem if you have really bad water. The tank supplies hot water from the top of the tank, the dip tube directs the cold make-up water from the inlet to the bottom of the tank. If the tube corrodes it mixes cold water with the hot at a higher point in the tank. A failure can also cause sediment to build up because the flow stay near the upper portion of the tank. Sometimes to inspect it you can remove the cold supply then remove the tube from that hole, but once you take it out it is best to replace it, they run about $30.

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