Thursday, June 8, 2023


What are the blue flakes coming out of the water heater?

gary-736Dear Gary,
I was winterizing our 10-year-old coach and flushing out the water heater. Some scale, I know, is usual, but what came out were lots of blue flakes. I am assuming that this is the glass lining of the tank and that the heater is basically totaled and not usable. I’d be very pleased if you could confirm that for me. —George N.

Dear George,
Unfortunately it is relatively easy to inadvertently scrape the inside of the tank if you insert a long wand or tube inside the drain plug as you flush out the inner tank.

One way to determine if the flakes are actually pieces of glass or the chemical result of something else, is to put a few of them in a cup of vinegar and see if they dissolve. If they do, then it’s probably some type of mineral deposit that reacted with the composition of the water in the tank. If they do not, they could be little pieces of the glass lining, though I’m not 100% certain they would be blue in color.

Assuming they are indeed glass slivers from the tank lining, the obvious safe action would be to replace the complete water heater (or at least the inner tank), and not take any chances of having them migrate further into the hot side of the fresh water system.

It could simply be some type of mineral reaction between the anode and the water PH and the heat associated with the heater. But finding out what those flakes really are is the key!

By the way, the photo above is what your Suburban inner tank might look like before it is glass-lined.

Read more from Gary Bunzer at the See Gary’s videos about RV repair and maintenance.




0 0 votes
Article Rating
Subscribe to comments
Notify of

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Inline Feedbacks
View all comments
Scott Taylor
5 years ago

I had blue “flakes” – some the size of a dime, coming out of my old heater, too. Ended up replacing the whole thing – was concerned it would have a catastrophic failure when we were travelling someplace inconvenient. It was the glass lining coming off – tank was pretty much “toast” – service tech said it was just about ready to split when he got it out, so glad I replaced it when I did! ST

5 years ago

I have never seen a HW tank that was made of “glass”?
Fiberglass yes, regular glass like a jar? No.

Jim D
5 years ago
Reply to  TP

It’s not MADE of glass, it’s LINED with glass on the inside, to help protect the tank from the corrosion caused by hot water. Many if not most hot water heaters are advertised as “glass lined”

Sign up for the

RVtravel Newsletter

Sign up and receive 3 FREE RV Checklists: Set-Up, Take-Down and Packing List.