Here’s a question from a reader of RVtravel.com about boondocking.Â
Hello Bob,
You gave me some great advice a few months ago when I asked about boondocking during our trip from FL to CA. We had a GREAT time! Now, here is a question for a situation that came up during that trip.
You’re not the only one to experience losing water from your fresh tank on the steep grades

The ideal fix would be for manufacturers to put the air vent (where the tank overflows) at the top of a tube extending up from the top of the tank a foot or so. This would prevent overflow. Maybe there is a code that prevents that factory modification.
I have heard of RVers both temporarily plugging the hole while driving on steep terrain and affixing their own tube into the vent hole and plugging the top with a tight fitting cap. In both instances don’t forget to remove the restriction when you set up camp. Your carrot (or a zucchini) would work also. I would suggest that you contact your RV manufacturer’s support page and ask how to stop the overflow and see if they have come up with a fix or a solution.Â
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Do you have a question for Bob? Email him at bob.rvtravel (at) gmail.com .
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I am sure that there is a check valve that is one way, that would let air in and not water out just like the diodes that we use on the lights when we tow. our car.
Bob,
I had this problem and it was severe. For my configuration in my motorhome, a complete re-do of the vent system was required (and possible). Not for everybody, but handy folks may be able to make use of some ideas. Here is the link on rvtravel:
https://www.rvtravel.com/check-your-water-tank-venting-and-save-water-2/
G.
We have 2 overflows on our Fresh Water Tank. I went to the hardware store and bought 2 shutoff valves. They are installed in the vent lines and I turn them off while traveling and back on when setup.
This was a cheap alternative and parts are readily available.