City water inlet regurgitates – Help!

By Chris Dougherty
Chris Dougherty is a certified RV technician. Here is a letter he received about the city water hookup from a reader while he was serving as RVtravel.com’s technical editor.

Dear Chris,
I have an issue with the fresh water from my fresh water holding tank shooting out the city water inlet connection when I turn on my freshwater tank pump. There is a trickle of water coming to the faucets. However, when the city water connection is hooked to external water source, everything seems to be OK. Do you know what might be causing this, and can it be corrected fairly easily? Thanks. —Jessie Lynn

Dear Jessie Lynn,
You’re in luck … sort of. This is a somewhat common problem, and a straightforward fix. Inside the city water connection is a small plastic, spring-loaded valve called a backflow preventer. The valve shaft itself is plastic and wears, releasing the spring, and occasionally a second small part that some manufacturers use to hold the spring in place. Basically, this is a non-serviceable part. I’ve tried a bunch of times, and whenever I have tried to glue the thing together, it doesn’t work long enough to make it worthwhile.

There are two things you can do. First, and best, is to replace the city water inlet. They’re available from any RV service facility or store. In most cases it’s three screws to pull it out and (hopefully there’s enough slack in the pipe) unscrew it from the plumbing system and replace. Make sure to use plenty of sealer on it if it’s on the outside of the coach. There are different styles and brands, so I would match up what you have and follow the manufacturer’s instructions if needed.

A second, temporary fix is to get a hose shut-off from a home center and screw it into the city water inlet. You’ll have this thing sticking out from the side of the coach, but it will work. The pieces of the valve will be floating around inside the valve head, so some flow restriction can be expected.

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