DIY Home Improvement Forum banner

Flushing out rust from hot water heater

1582 Views 10 Replies 8 Participants Last post by  Fix'n it
I have a gas water heater, and i was talking to a plumber about me flushing out the rust from it. I have always heard that I should flush out the rust through the valve at the bottom once every few months.. The plumber told me this is a myth and it doesn't actually help or hurt the unit. I searched this topic online and i see arguments for both sides.

What is the truth? What is the science behind your claims?

Thank you,

1 - 11 of 11 Posts
Minerals in the water are heavyer then the water, they settle to the bottom of the tank.
If the bottom of the tank is covered with hardened up minerals it's going to take longer to heat the water.
Your plumber is wrong.
If you have old steel pipes, or an old steel lined heater trying to drain the rust out would be useless.
I have a brand new Bradford White gas water heater if that helps. Brand New as in 3 months old. All the pipes leading up to and Away from the heater are copper pipes
Then just hook a hose to the bottom of the tank and drain off some water about every 6 months.
The heater will last longer.
The plumber wants to sell more water heaters. I flush mine annually, always get lots of crud shooting out. Mostly white chunks of corroded anode rod. It's also a good idea to inspect and if necessary, replace the inexpensive anode rod every 3-6 years. If you do that and flush, your tank could last for decades.

Don't forget to test the T&P valve every time you flush. Just put a bucket under the discharge pipe and pull the little lever a couple times.
flushing rust out of water heater

The above by Tylernt is excellent advice. It will double the life of the water heater.
i have heard that if the heater hasn't been flushed in a while, it shouldn't be flushed. as the valve could leak or break.
any trueth in that ?
Best to start when the unit is new every six months or yearly. will prolong the life and efficiency of the unit, on older units your just looking for problems.
i have heard that if the heater hasn't been flushed in a while, it shouldn't be flushed. as the valve could leak or break.
any trueth in that ?
Why that urban legend got spun is that once in awhile a piece of sediment gets lodged in the drain valve and you can't turn it completely off.

If you got a garden hose cap in advance you could hurriedly screw that on so you don't end up with all 40 gallons of water out on the floor.

One other issue is if the tank is almost rusted out and the layer of sediment is keeping things together for the time being. Once you flush out and stir up the sediment, the bottom of the tank finally breaks through and springs a leak. (Gas and oil heaters: ) The layer of sediment inside also hastens the rusting out of the tank because it is an insulating layer and the bottom of the tank gets hotter than normal, damaging the glass or porcelain lining.
The original post was about flushing rust from a gas water heater. The plumber is entitled to his/her opinion. Then we find out that the water heater is only three (3) months old with copper piping. The question of rust here is moot. IMO-electric water heaters will build up sediment in the bottom quicker than a gas unit will. This also depends on the water in your area. Flushing out some water from a water heating unit on some type of schedule is not a bad idea no matter which type unit you have or what the water conditions are. Sediment is not good in water heating units.
i'm still afraid to try it. bad things like to happen to me. and that could be a can of worms.
1 - 11 of 11 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.