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?________________

On ours the FW tank bulges down when full. It is because the potable water tank is made of a more flexible white plastic stuff than the more stiff dark coloured plastic used for the grey and black tanks.Not had any issues with any water left in there when "empty" if there is any. Ours does not need any extra supports underneath. In fact a support would stop it from bulging down so where would it bulge instead or would it just not fill as much? Not a clue.

BFL13 wrote:On ours the FW tank bulges down when full. It is because the potable water tank is made of a more flexible white plastic stuff than the more stiff dark coloured plastic used for the grey and black tanks.Not had any issues with any water left in there when "empty" if there is any. Ours does not need any extra supports underneath. In fact a support would stop it from bulging down so where would it bulge instead or would it just not fill as much? Not a clue.I'm sure the bulge was caused by the weight of the water in the tank. When I observed this bulge, the tank was only about 1/5th full, so there was very little water weight.From what I remember, the tank was supported a bit better in the middle, and the left side had the feed line and drain plug on the bottom.It would have made perfect sense if the bulge had been where the feed line and drain plug was, but it was on the opposite side.Is there a chance that the builder goofed and installed the drain and feed line on the wrong side?

A goof is always possible. Our FW tank almost fell out because the rails it sits on were set too far apart. I had to shim the movable rail so it was closer to the fixed rail to give the tank full support on both the front and back ledges of the rails it hangs from.I suppose you could shim under one side of the tank where it hangs on its rails so it drains better to the other side. Not tried it. Ours is all enclosed with underbelly so it is a major PITA to get at it all.

BFL13 wrote:A goof is always possible. Our FW tank almost fell out because the rails it sits on were set too far apart. I had to shim the movable rail so it was closer to the fixed rail to give the tank full support on both the front and back ledges of the rails it hangs from.I suppose you could shim under one side of the tank where it hangs on its rails so it drains better to the other side. Not tried it. Ours is all enclosed with underbelly so it is a major PITA to get at it all.Oh, man.What's a 'PITA'?

bulge in potable water tank | Good Sam Community

BFL13
Explorer II
Feb 26, 2014
PITA = pain in the rear. Actually in this case, neck. Under the trailer unscrewing all those rusted in screws holding the underbelly on where you have to raise your head a bit. Of course the bifocals won't focus at those distances either, so that is even more fun. :(
kcny
Explorer
Feb 26, 2014
PITA - Pain In The A..
Rmack1
Explorer
Feb 26, 2014
BFL13 wrote:
A goof is always possible. Our FW tank almost fell out because the rails it sits on were set too far apart. I had to shim the movable rail so it was closer to the fixed rail to give the tank full support on both the front and back ledges of the rails it hangs from.

I suppose you could shim under one side of the tank where it hangs on its rails so it drains better to the other side. Not tried it. Ours is all enclosed with underbelly so it is a major PITA to get at it all.

Oh, man.

What's a 'PITA'?
BFL13
Explorer II
Feb 26, 2014
A goof is always possible. Our FW tank almost fell out because the rails it sits on were set too far apart. I had to shim the movable rail so it was closer to the fixed rail to give the tank full support on both the front and back ledges of the rails it hangs from.

I suppose you could shim under one side of the tank where it hangs on its rails so it drains better to the other side. Not tried it. Ours is all enclosed with underbelly so it is a major PITA to get at it all.
Rmack1
Explorer
Feb 26, 2014
BFL13 wrote:
On ours the FW tank bulges down when full. It is because the potable water tank is made of a more flexible white plastic stuff than the more stiff dark coloured plastic used for the grey and black tanks.

Not had any issues with any water left in there when "empty" if there is any. Ours does not need any extra supports underneath. In fact a support would stop it from bulging down so where would it bulge instead or would it just not fill as much? Not a clue.

I'm sure the bulge was caused by the weight of the water in the tank. When I observed this bulge, the tank was only about 1/5th full, so there was very little water weight.

From what I remember, the tank was supported a bit better in the middle, and the left side had the feed line and drain plug on the bottom.

It would have made perfect sense if the bulge had been where the feed line and drain plug was, but it was on the opposite side.

Is there a chance that the builder goofed and installed the drain and feed line on the wrong side?
BFL13
Explorer II
Feb 26, 2014
On ours the FW tank bulges down when full. It is because the potable water tank is made of a more flexible white plastic stuff than the more stiff dark coloured plastic used for the grey and black tanks.

Not had any issues with any water left in there when "empty" if there is any. Ours does not need any extra supports underneath. In fact a support would stop it from bulging down so where would it bulge instead or would it just not fill as much? Not a clue.

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bulge in potable water tank

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