Almost Lost Freshwater Tank

We just picked a new (to us) travel trailer so I was reading through the manual to see what I needed to know... it specified hose size and running the hose faucet at half open so as not to over fill the fresh water tank... They showed a picture of the supports under broke in half when there was 60 gallons of water in a 40 gallon tank. It was explained that the air has to have a place to escape while filling and when filling too fast (or using hose too big), the openings (around hose and the small vent) are not large enough to allow the air to escape and you end up with bulging tank, that can break things... Just think of a pregnant water tank.. Our old trailer had the tank under the sofa so if it bulged, it did not break anything... glad you got it fixed..

The tank evidently was not fully resting on the original supports when built but the camper is four years old so why did it wait this long to fail? The technician rebolted the supports to the frame and added bracing under the tank. There were only a couple of screws and a bolt holding the tank in place. I think we were very lucky the tank did not fall out during the 400 mile tow to get here. We always travel with fresh water.

Did they add additional crossbraces? Riveted, bolted or welded?

Let me guess, the flake board supporting the tank between two crossmembers rotted and flexed down? I just went through this with mine. Luckily, I caught mine before it happened on a trip. Glad it worked out for you.