Re: Vinylester Potable Water Tanks??
There is a vinylester resin specifically approved for potable water: I've built water tanks out of it.
It's called Dion Impact. Got it from Composites One. Had to add our own cobalt, and it's harder to bubble-pop (the bubbles seem to keep coming back, as though it's fermenting), but it's good stuff.
I'd be comfortable using normal vinylester, but this client needed the gov't-approved stuff.