I purchased two very pricey Wedco Water Cans about a year or so ago. Haven't used them all that much but started to notice some rust spots forming around the inside mouth of the cans. I figured a little sanding and primer/paint some day would fix the problem. [don't know what the coating is]
I plan on taking them on a Xmas camping trip and was filling them up today and noticed the rust was a little worse. Other than perhaps scratching the food grade coating [not likely] with a hose end I don't know why the rust.
So for grins I stuck a flashlight down inside and noticed rust all along the interior seam on both cans. I always let the cans dry out after use and here in the southwest that's not hard to do.
So just a heads up folks. A little rust won't bother me and I'm sure the wife won't ever find out.
Bob in Tucson