Thursday, March 23, 2023


Ask Dave: Water is seeping into freshwater tank when hooked up to city water.

Answers to questions about RV Repair and Maintenance from RV expert Dave Solberg, author of the RV Handbook and the managing editor of the RV Repair Club. This column appears Monday through Saturday in the RV Travel and RV Daily Tips newsletters. (Sign up for an email reminder for each new issue if you do not already receive one.) Today Dave discusses an RV’s freshwater system.

Dear Dave,
“I have a Starcraft Autumn Ridge trailer. When I hook up to city water at an RV park or campsite to run my shower, toilet, etc., it all works good. However, water has been flowing into my freshwater tank at the same time. Can’t figure out why. Have not done anything different.”  —Jere

Dear Jere,
The issue could be one of two things, depending on how your system is set up. Most of the time it’s a faulty or plugged water pump check valve. Plastic shavings can easily get into the system during the manufacturing process as well as calcium and other particles from hard water available at campgrounds. I have experienced water that actually had sand particles in it and plugged all the filters, check valves, and screens. It’s easy to clean out the check valve as it’s usually located on the inlet side of the pump.

It could be the fill valve

The second issue could be a leaky or defective fill valve. Some units are equipped with a diverter valve that allows you to fill the tank while connected to the campground source. Put in one direction it provides pressurized water to the entire plumbing system known as city water. Turn the valve and it directs water to the freshwater tank to fill without having to disconnect and insert the hose into the gravity feed.

This valve can be harder to replace if it is incorporated into the service panel. Then it requires dismantling most of the plumbing lines to get access to the mounting bracket and the back side of the panel.

This switch is connected to the panel with a nut on the back side. So, as you can see, it’s not an easy replacement. The other connections on this panel are held in with screws to the flange from the outside.

You might be able to get a plumbing diagram from your RV manufacturer. Otherwise, it’s a matter of trial and error, removing one line at a time.

Leaking valve difficult to replace

We had a similar situation with a 2003 Winnebago Brave that had a leaking valve which made the water pump start up intermittently. It was a real adventure getting it replaced. We basically had to remove almost every line and take out the panel. Luckily, they use PEX tubing and compression fittings called Flair-It™, so we did not have to cut lines that were pinched to the fittings.

Read more from Dave here

Dave Solberg worked at Winnebago for 15 years developing the dealer training program, as marketing manager, and conducting shows. As the owner of Passport Media Creations, Dave has developed several RV dealer training programs, the RV Safety Training program for The Recreation Vehicle Safety and Education Foundation, and the accredited RV Driving Safety program being conducted at rallies and shows around the country. Dave is a leading expert in the RV industry and author of the “RV Handbook” as well as the Managing Editor of the RV Repair Club.


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Tom Herbert
1 year ago

Had the same problem last year on my 2016 Cedar Creek and replacing the diverter valve was easy and fixed the issue. I think the minerals in the water of the various campgrounds was the problem. My valve was easy to get to so it was a 15min. job. Cost $90 for the plastic valve, though!

1 year ago

Thanks for the link to Flair-It and their PexLock system.

1 year ago

Very good example of why you need a quality water filter ahead of the water fill.

David Telenko
1 year ago

I’m a senior & I like the old ways too, but like the new & BETTER ways most of the times. On our Forest River we have a water manifold system thats really cool as you can manage ALL of your water needs, even shut them off or throttle them down for both hot & cold!

1 year ago

Also, if the unit has a water saver in the shower, that valve might be in the wrong position.

Jesse Crouse
1 year ago

Sometimes the old way of doing things- a fill tube- are more of a common sense way to do it. My 98 Bounder was old school, my 06 Phaeton new style.

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