Solving RV Slow Fresh Water Tank Fill


It’s a pretty common complaint among RV owners — it takes forever to fill my fresh water tank and the water keeps “backing up” while filling.

This was a big problem for us. We have two 50 gallon fresh water tanks and it would take an hour to fill them. The Owner’s Manual warned of this and states to fill the tanks slowly with the water bib turned to a low volume. This was completely unacceptable.

I finally devised a solution that cost very little money and will not take much time for anyone to adopt.


Most RV’s have a fill hole for the onboard tanks and a “city water” connection to connect directly to a water bib. Since we almost never camp where we can connect to water, we must rely on water we fill our tanks with.

Water tank fill (left), vent (center), city water connection (right)

Critical Success Factor #1

Your vent must be clear and free from any obstructions. Just a small bit of anything in the vent will cause you problems. When filling the tank in incoming water needs to displace the air in the tank and this can only happen if the vent is completely clear.


I periodically blow out the vent with a bit of low volume compressed air. Another solution that works is to hold a piece of hose over the vent and blow into it — this works!

Critical Success Factor #2

Hoses & Fittings

It is best to connect your fill hose to a fresh water hose adapter like the one below.


However, this along with an unrestricted vent did not solve our problem. So I decided to cut a piece of hose so I could push it down the fill tube into the tank.


This didn’t improve fill times either.

I checked all the fill hoses connected to the tanks and all the vent tubes for mis-routing or kinks and everything was A-Okay. Larger vent hoses might have helped, although the connecting nipples at the tanks and the fill hole would almost impossible to change.

The Solution That Worked

I found that if I stuffed a rag into the fill hole around the hose, it kept water from backing up and more efficiently forced the air in the tanks to move through the vent systems. This didn’t create unwanted extra pressure. But who wants to stand around holding a rag in place.

The Solution Was Simple

You will need two items, a Water Bandit (also known as a water their) and a fitting that is used to connect two water hoses (a garden hose adapter with 3/4″ FHT at both ends).


Water Bandit

This is used to connect a hose to a damaged water bib or a campground water bib that has no threads.



The Water Bandit slides over the bib and you then connect your water hose to it

Because the rubber part of the Water Bandit is soft and pliable and larger than the inner diameter of most RV water fills, it will fit easily and securely into the fill hole. You will then need the garden hose adapter to connect the water hose to it.

It works!

Note that I am using a white water hose. Water hoses that are designed for potable water are white. We carry 3 of these hoses; two 50 foot hoses and a 25 foot hose. There have been a few times where we were camped in campgrounds that have water, but not at each site. 125 feet of water hose has usually allowed us to fill our tanks without moving the camper — site selection is important 🙂


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