bulge in potable water tank

Rmack1 wrote:
On my last trip, I looked under the trailer to determine the exact amount of water left in my translucent water tank. The level could be seen.

I happened to be looking on the side (port) that had the system feed and drain plug, and all looked well. However, on the other side of the tank, reaching all the way to the other side of my TT, I noticed a large area between the metal supports that was bulging down. It formed a depression inside the tank that extended a couple of inches or so lower than any other part of the tank. Obviously, water will get trapped here that will not drain from the drain plug if the unit is level.

What caused this? It seems obvious that the tank should have had more supports in that area. Has anyone else ran into something like this? Has anyone been able to do anything about it?
________________

This is a typical design flaw in most slide type RV's. The tank is flat and has a large surface area. The manufactures don't support them well enough. The water that remains in the tank is a health hazard, think Mexico! don't drink the water.

On top of the mounting problem most of the water systems suffer another problem of the potential to over pressure the tank when filling with a hose. If you stick the hose in the filler inlet there in not enough clearance for the water to bypass when full. The combination of this clearance problem and the small overfill hose the tank can be over pressured to a level that will cause damage from excessive expansion.

The procedure to fill the tank is to use a small diameter hose to fill the tank and use a slow rate of fill.
MM49