I'm new here and not sure if my problem belongs here.I just returned from a trip where I had to use my fresh water tank in my Evergreen 5th wheel. I had to fill before moving to my campsite and topped the tank until it was over flowing.We ran out of water in 2 and a half days. Normal usage has always been 4 days. Took the 5th wheel and filled again, topping off as before. Both the filler and air vent had water coming out.We used very little water but everything acted as if we were empty. I thought the pump was bad. I bought a new one, installed it. No change.The sensors on the tank were showing 1/3 both times.After the first fill they showed full. After the 2nd fill they showed 2/3rds.I got home opened my tank drain and a large amount of water came out. I would guess some where between a 3rd to a half a tank.Does anyone have any ideas?Could it be the pickup line?I cannot access the tank from above.It will be a huge project to drop this tank and I physically can't do it, so I.E expensive repair.Any help or ideas would be appreciated.WWBELL

Not sure but could it be a air lock? (air in water line).

I've heard of pieces of plastic floating around in the tanks; these are pieces left over from molding of the tank or trailer construction. Some are small but not small enough to be sucked up by the pump others are large (openings for hoses, fill pipe, vent ...etc. These pieces as the tank empties can block the pickup line then when you fill they float away from the pickup line.The only way to fix this would be to access the tank, try to remove the debris or change the pickup end so it's like basket with multiple openings.

It could be pickup line positioning or blockage in the tank.I suspect it could also be an air leak somewhere around the suction side of the pump, maybe an antifreeze suction line valve that isn't quite closed or a loose fitting.

Any sight of a filter in the pump intake line ? You never mentioned one word of a filter,....first place I would look.

I would fill the tank to overflowing, and then drain it, but this time measure the amount coming out. Without knowing if the tank is getting full there is no point in doing plumbing work.

Fresh water tank. | Good Sam Community

Fletch_Rider
Explorer
Feb 20, 2016
I had a very similar experience. Began to occur after I had filled the tank and then towed the camper. I eventually cupped my hand around the water inlet and basically pressurized the tank until the vent line spit out water and then there was a sort of burbing and air began rushing into the vent line and all was right with the world again. I can't see the entire vent line, so the only thing I can think of is water was sloshed into the vent line while traveling and sat there until I forced it out. You could probably use air to make sure the vent is open as opposed to forcing water into the tank. But be careful not to use greater than 35 psi regardless of which approach you try or you'll have a much bigger problem on your hands.
RJsfishin
Explorer
Feb 20, 2016
This post is very correct, (except for the psi)
If a vent hose gets water logged, and runs more vertical than horizontal, it can cause a real problem in filling.
I have that problem existing in my current MH.
When it happens I use a 6" pc of hose in the vent ext fitting. and simply blow the vent line clear of water,....it doesn't take much human pressure to clear it. I always threaten to remove the (what must be) sag in the vent line, but never do.
But this still has nothing to do w/ the OP not able to draw water off a tank that is 1/3 to 1/2 full.
I would still believe there is access to an inline filter some where.

Just a caution,....don't ever put more than even 2 to 3 lbs pressure in a flat sided plastic tank,....and even that mite be too much.

Fletch Rider wrote:
I had a very similar experience. Began to occur after I had filled the tank and then towed the camper. I eventually cupped my hand around the water inlet and basically pressurized the tank until the vent line spit out water and then there was a sort of burbing and air began rushing into the vent line and all was right with the world again. I can't see the entire vent line, so the only thing I can think of is water was sloshed into the vent line while traveling and sat there until I forced it out. You could probably use air to make sure the vent is open as opposed to forcing water into the tank. But be careful not to use greater than 35 psi regardless of which approach you try or you'll have a much bigger problem on your hands.
Fulltimer50
Explorer
Feb 20, 2016
It could be helpful to know the year and model of your rig.

Forum Discussion

Fresh water tank.

About Technical Issues

Related Content

Fresh Water Tank Treatments

Fresh Water Tank Drainage ?

Tioga Fresh Water Tank

fresh water tank

Jayco fresh water tank