Cleaning Sediment From A Water Heater

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by Tim Fulton on November 16, 2010

I recently insulated my water pipes, and while doing so was reminded that I should probably flush out my hot water heater. Over time, sediment builds up in the tank and especially with gas water heaters, it reduces the efficiency because the sediment acts like a insulator between the flame and water. As far as I know this hot water tank has never been cleaned out. Of course, this led to an eventful afternoon…

I started by turning the temperature setting all the way down on the heater so it wouldn’t fire up while working on the heater. Then I drained some water out of the drain port as shown above. I got some slightly colored water coming out but nothing like what is shown above. With a little help from the forum I figured out I’m just draining a tank that is already full of water. If I want to really wash this out, I need to drain the whole thing and blast it from the top with cold water. So, this is what I did.

cleaning water heater

Once the tank was mostly drained, I started blasting it with intervals of water from the cold inlet to stir up the sediment in the bottom of the tank. What you see above is the first 20 or so gallons of water that were removed once this was started.

cleaning water heater

After a while, I saw it wasn’t clearing up very quickly at all. I went and got the hose and hooked it up to wash the tank without me constantly moving buckets around.

Once it seemed to be running clear I tightened up the drain valve. It did leak like most tutorials say. I did not have a cap handy, so I ended up removing the valve, cleaning it and reinstalling it. I was happy to see it did not leak.

With the drain valve shut, I ran the hot water in my downstairs utility sink for a while and still noticed it was cloudy. I ran the water until it ran clear. Finally, I turned the heater temperature back up to heat the tank again.

Overall, the process took me about 3 hours. I can only imagine the effect all the sediment had on my gas water heater. I’m looking forward to increased water heating efficiency and will be doing this a bit more often from now on. Next time I’m sure it’ll be much quicker.

{ 1 comment }

1 Indyplumber February 20, 2011 at 9:37 pm

A good thing to install on your water heater to help flush it out is a full port ball valve. This valve has an opening straight through it instead of a normal drain valve that has stops and seats that can clog with the sediment. The flushing goes much faster and likely won’t clog unless the sediment has hardened.

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