Forum Discussion

CJW8's avatar
CJW8
Explorer
Jul 16, 2015

How to know if fresh water tank is full?

New 5th wheel toyhauler has 90+ gallon fresh water tank. The under belly is enclosed so I cannot see the tank. The tank gauges are inside the camper but they are notoriously undependable and even if they work properly they only give you 4 points of resolution.

How full can you get them? Till it comes out the fill vent? I am tempted to fill till gauge says 3/4 and slow fill rate to a trickle till it comes out the vent. Will wait to see what others do.

31 Replies

Show More
  • _tpc_'s avatar
    _tpc_
    Explorer
    Jul 16, 2015
    When I first got mine, I use to play the dance of fill and run in and check, fill...etc etc. Then I talked to some people, most of which said they fill it till it "burps" back at you, then you know its full.

    So I say just fill it till some water comes back out at ya. Mine usually doesn't come out the vent hole so much as it does right out the gravity fill.

    Edit to add that I fill mine up at the campground, not prior to leaving for the trip. I'm fine with driving short way to the site, but I don't know how much stress 90 gal of water would put on your rig bouncing down the road.

    Mine is only 30 gal, but like yours, it is enclosed.

About Fifth Wheel Group

19,021 PostsLatest Activity: Jul 26, 2025