I have a Bradford White NG fired water heater installed in summer of 2018. The past week or so my hot water while shaving or showering has a slight "musty" smell and I am wondering if this is due to the heater needing a good flush?

I realized I never flushed it all this time and think I may need to do this?

I do have a floor drain nearby thankfully and it shouldn't be an issue, I just have never done this. Shut it off, shut off the water and attach hose and let 'er rip? Do I let it fill up again and flush a second time?

Any advice/tips would be appreciated. Not noticing it with my cold water (city water) so I don't think it's coming from there.

quote:

Shut it off, shut off the water and attach hose and let 'er rip?

No, it'll take forever if you do that and it'll never "rip." You need to open the relief valve so that that it sucks in air as it's draining out liquid.

Here is a Nov 2025 thread on draining hot water heaters that has additional tips and tricks.

We went through this for years
We could not figure out what was wrong. Was it a well issue, a hot water tank issue, etc..

It could be bacteria or organic matter is growing in your water heater tank, often due to sediment buildup or a corroding anode rod.


When she bought the house, the hot water heater was at least 12-15 years old and the anode rod had never been replaced. We replaced the rod but the hot water heater was shot.

((The water is pretty hard here and we have to replace the water filter every month.))

We were advised by a plumber to:
Flush the Water Heater

Temporarily raise the heater temp to 140°F (use caution!) to kill bacteria, then lower it to a safe 120°F.

Replace Anode Rod

I know a few people who added 1 pint of 3% hydrogen peroxide to the tank, let it sit, then flush.

quote:

Temporarily raise the heater temp to 140°F (use caution!) to kill bacteria, then lower it to a safe 120°F.

This. The other option is to leave it at 140, be careful and enjoy whiter whites, cleaner dishes, and no smell ever again.

Couldn't hurt to raise the water temps temporarily to see if that will do the trick, as noted above. Simple and quick and no extra cost (though be careful during the period of extremely hot water). If that works, you haven't had to spend any money/time on draining, replacing electrodes, etc.

I tend not to like implementing solutions that take extra time/money till I know the cause. So, if it were me, before starting in on fixes, I'd do some diagnosing. Water vapor and the smells thereof are more easily detectable at higher temps - more moisture gets put in the air and so your nose gets more action. So it's at least theoretically possible that the water supply is an issue that is only noticeable when hot.

Since you're noticing it with hot water and not with cold, you could be sure whether it's your hot water system (heater/pipes) vs the water supply by taking cold water and heating it up on the stove/microwave and seeing if the same smell happens.

If it does, the issue is the water supply and nothing you do to the water heater will matter. If it doesn't you've pinned down the issue to something in your heater or the pipes to/from it.

Then, I'd see if the local utility folks supply water test kits and see if I could get one for free. If not, I'd order home test kits that cover minerals and bacteria and see if I could identify the cause.

Water heaters used to be at 140 or higher, then stupid-proof safety became a thing and so children no longer learn that water can burn.

That 140 also kept things from growing in it. Almost like the old timers knew what they were doing.

City water or well water?

If on a well, it's likely iron bacteria. There's not really a good solution to that other than shocking (bleach) the well every once in awhile. I've tried the 140F temps and it didn't work for me.

I'd be surprised if treated city water has a bacteria problem. I'd start with flushing the tank and maybe run some bleach through it.

quote:

Originally posted by Gustofer:
I'd be surprised if treated city water has a bacteria problem.

Surprise, surprise, surprise! The worst offender was my parent’s water heater in their condo on Ninth and 9th in Naples, FL. Most definitely on city water. Every time the left on vacation or went north, they turned the water heater off and every time they came back to smelly hot water. This is how and why I learned about SRB, sulfate reducing bacteria. Leaving the water heater on and turning up the temp solved the problem. Same problem and same solution at a couple of our other properties as well.

PASig should flush the sediment out and crank the heat up afterwards.

quote:

Originally posted by onegeek:
Water heaters used to be at 140 or higher, then stupid-proof safety became a thing and so children no longer learn that water can burn.

That 140 also kept things from growing in it. Almost like the old timers knew what they were doing.

Electric heaters actually were set from the factory at 155 in late 1960's when I first started in the business. Many dishwasher instructions said they required 140 plus degree water. Now they all have internal heaters to boost the temp...

The factory settings slowly were reduced for safety, and energy saving, reasons over many years so now we should just call them warm water heaters

I prefer hot water not warm... I still keep mine at 145. Funny, most thermostats will still go 150 or more.

I won't be surprised if the .gov in all its infinite wisdom requires non adjustable thermostats at 120 in the future.

Shhhhhh!
Don’t give them any ideas. They ruin enough.

I thought that temps higher than 140F were not advised if using PVC pipes. Not a plumber but I think that's what I've been told.

The water coming out of the faucet ranges from 125F down to about 110-115F. It hotter after using (ie - laundry or bath) and the water heater fills and heats. But then I guess it cools down and reaches a steady state less than 120F. Not sure if that's a sign of age or not.

It could be that the anode has been used up and now the water is etching the other metals in the tank. Have you changed it?
If not, now is the perfect time to. It’s a 1 1/16” socket, a big cheater bar and someone to hold the tank-don’t empty the tank first, the water will help hold it down.

But yes, follow the other guys suggestions on how to flush it.

I do mine annually and write on the tank with a sharpie so I don’t forget.

quote:

Originally posted by konata88:
I thought that temps higher than 140F were not advised if using PVC pipes. Not a plumber but I think that's what I've been told.

The water coming out of the faucet ranges from 125F down to about 110-115F. It hotter after using (ie - laundry or bath) and the water heater fills and heats. But then I guess it cools down and reaches a steady state less than 120F. Not sure if that's a sign of age or not.

PVC is rated to 140 degrees and not used for hot water lines. Instead, CPVC is used for hot water lines as it is rated to 200 degrees.

I am having my plumber come out the last week of December to change the anode rod and flush it, then I’ll do it myself from then on after that. Guess I shouldn’t have let it go 7 years.

quote:

Originally posted by MikeinNC:
It could be that the anode has been used up and now the water is etching the other metals in the tank. Have you changed it?
If not, now is the perfect time to. It’s a 1 1/16” socket, a big cheater bar and someone to hold the tank-don’t empty the tank first, the water will help hold it down.

But yes, follow the other guys suggestions on how to flush it.

I do mine annually and write on the tank with a sharpie so I don’t forget.

When ai was having issues in one of my rentals a few years ago my plumber recommended I get a powered anode rod and change it myself. Other than being a bitch to take off it was straight forward and no issues since…


https://www.lowes.com/pd/CORRO...HxGrlCEaAu2sEALw_wcB

Update:

Plumber came and removed the old anode rod which was pretty ugly and pitted badly on the length but the top 2-3 inches and bottom 2-3 inches were crumbling away badly and virtually gone.

I also had the temp a bit too low I think at around 120 which I adjusted up to about 132, my kids are a little older now since it was installed and no more babies so I think I will be OK safety wise.

Of course Bradford White cannot make it easy, the rod is not separate like most andode rods but instead is part of the hot water line out so the plumber had to cut the copper pipe and redo it all.

He drained it and told me there wasn’t actually a lot of sediment but put a cup of bleach into the tank and filled it back up then had me flush it from every faucet.