Per the instructions with my new water heater, I drain a gallon from the bottom every month. The previous owner of my home never did anything and that water heater started leaking, hence the replacement.

The water in our area is hard-ish, but I hesitate to call it hard. I've never seen this in all the decades I lived in this area but, when I drain the water, there is a collection of minerals, sandy looking, in the bottom of the bucket. Maybe a tablespoon amount.

This has been going on for a year. At first I thought it might be residue in the pipes. We had some of the plumbing replaced cause it was in bad shape but not a majority of it.

How unusual is this and should I be concerned or do anything about it? I've lived within 10 miles of my current home and I've never seen that before though I'll admit I've not been as meticulous about taking care to drain the water heater or doing it in a bucket first. Have I just never noticed it before?

  • One gallon? That differs from every flush procedure I've encountered, ever. :P
    – isherwood
    Apr 21, 2016 at 15:02
  • @isherwood It's not a flush. It's monthly maintenance to keep sediment down.
    – Rob
    Apr 21, 2016 at 15:18
  • Makes sense. Does it still call for a full flush?
    – isherwood
    Apr 21, 2016 at 15:32
  • @isherwood Don't recall. They do say the safety valve on top should have a gallon or so run through there every six months or once a year. Don't remember reading anything about a full flush. If it matters, I think it's the type with the swirl motor in it.
    – Rob
    Apr 21, 2016 at 17:46

1 Answer 1


This is completely normal and is the reason it is suggested you drain and flush your tank periodically. Even better than just draining a gallon of water is to turn off the tank (either kill the electricity or turn off the gas valve), shutoff the water to the tank, drain the entire tank, and then with the drain open, run the water to flush any remaining sediment away.

The discharge will be any colour from white to black depending on the mineral contents of your water.

Be careful when draining the tank as the water will be very hot.

Once complete, re-fill the tank completely and then turn on the power or re-light the pilot and turn the gas valve on.

  • 2
    When I drain my hot water tank (infrequently), I shut off the heater before I take a shower or run some laundry. That way I don't waste the hot water or risk burning myself.
    – Hank
    Apr 21, 2016 at 15:11

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.