Fresh water tank emptying 20%

Miwok

2015 CSS: Our freshwater tank only empties 20%. The tank is clearly 80% full. The pump has been confirmed as working fine. As the valve is at the front of the tank (design flaw?), has anyone tried installing a valve at the rear?

A group of competent RV problem solvers concurred with the above analysis. This problem must have been addressed by someone previously. 

Sharon_is_SAM

Is the valve blocked?  Try blowing air into the valve and see if there is debris settling in the valve.

Miwok

Tried. Problem persists. We fill up the tank and get the same 2 gallons only out.

Sharon_is_SAM

Even with the tongue fully down?

Miwok

we tried that as well without notable success. It would not have been a sustainable solution, for tipping the tongue down when we need water would not make sense. 

rfuss928

Is it possible the fresh water vent tube is blocked?  After a couple gallons are used the tank becomes air locked...

jbajor

When you fill tank with city water, do you do so until you get water coming out the overflow?

Sharon_is_SAM

Is your problem with draining the tank or with using the pump to draw water?
Good idea @rfuss928!

@Miwok - is there a vent tube next to your fill spout?  If you leave the fill cap off, can you drain the tank?

ScottG

You have a 2015. Is this a new development? (Or a new-to-you camper?)