Throughout the years I have shared temporary fixes for an inoperable water heater and furnace, suggested back-up plans when things don’t work, and what to pack in your electrical bag to keep your 12-volt system up and operating when something goes awry.
Here’s another tip to remember. Just recently the check valve on my city water inlet decided to act up, allowing fresh water to exit the RV when the water pump was turned on. Not a good thing to happen when you are boondocking with limited water in the tank.
For those just entering the RV lifestyle, there is a check valve behind your city water hook-up. The valve is designed to let pressured city water enter the RV’s plumbing system when hooked to a charged hose bib via your water hose in an RV park, and prevent the water pump from pumping water out of your potable water tank onto the ground when not hooked to a charged hose bib.
Needless to say, when the check valve malfunctions while dry camping miles from a potable water source, losing some or all of your freshwater can put an end to your campout.
In my case, the telltale sound of the water pump “zipping” frequently alerted me to the problem. Many times when a check valve fails to seat properly, you can just depress the check valve spring from the exterior of the RV allowing some water to gush out. This will often flush out whatever is preventing the valve from fully closing.
This didn’t solve the problem in my case. The next option (temporary fix) is to plug the city water hookup. Most RVers (myself included) do not carry a male garden hose plug with them.
The next question becomes what do you have to serve as a plug? Things that an RVer is likely to have with them that feature male hose threads are: water pressure regulator, fresh water hose, water wye, or a blowout plug used for winterizing.
Let’s look at how each of the items above can be used to temporarily solve your problem:
Water pressure regulator: Find a non-toxic disc-shaped item (approximately 7/8” in diameter) that will fit into the city water hookup. A United States nickel or game counter (small poker chip) are examples. Place the disc against the hose washer in the city water fitting and then screw the regulator in place to plug the leak.
Water wye: If the water wye has shutoffs on the outlets, you can just screw one of the male ends into your city water hookup and the problem is solved. If there is not clearance to do so, screw your water hose into the city water hookup and plug the other end of your hose with the wye. If the wye does not have shutoffs, use the disc method described above with the pressure regulator.
Freshwater hose: You can screw the male end of the hose into the city water hookup and then kink the hose shut. Not the best on your hose, but it will work until you break camp.
Blowout plug: If you have the good one with the automotive valve stem, just screw it into the city water hookup and you are done. If you have the cheap one with no valve stem, use the disc method described above for the pressure regulator.
Avoid leaving your water pump turned on when you are away from your RV. You never know when a plumbing failure might occur and nobody wants to find their RV flooded or their fresh water pumped out on the ground as described in this article.
Remember, RVs are a house on wheels, and just like a house, things can and will go wrong. However, don’t let this stop you from RVing, just be prepared for these little bumps in the road and treat them as just another adventure.
See also: Why You Might Consider Installing An RV Water Filtration System In Your Rig [VIDEO]
Dave Helgeson’s many roles in the RV industry started before he even had a driver’s license. His grandparents and father owned an RV dealership before the term “RV” had been coined, and Dave played a pivotal role in nearly every position of an RV dealership. He and his wife Cheri launched their own RV dealership in the Pacific Northwest. The duo also spent 29 years overseeing regional RV shows. Dave has also served as President of a local chapter of the Recreational Vehicle Dealers Association (RVDA), worked on the board of advisors for the RV Technician Program of a local technical college, and served as a board member of the Manufactured Home and RV Association. Dave’s reputation earned him the title of “The foremost expert on boondocking,” bestowed by RV industry icon, the late Gary Bunzer (The RV Doctor). When he’s not out boondocking, you’ll find Dave in the spotlight at RV shows across the country, giving seminars about all things RVing. He and Cheri currently roam in their fifth travel trailer, with Dave doing all the service, repair and modifications to his own unit.
Pete Miller says
Plastic threaded hose caps are about $2 for two at Home Depot.
Dave Helgeson - Adventures in RVing says
Yes the are. If only there had been a Home Depot out in the boonies when my checked valve failed. I now carry one. Thanks for sharing.
Bloggin Brandi says
I had an issue with my fresh water valve as well. Come to find out it was on tank fill instead of normal so there was no pressure. Also, the propane was turned off so there were all kind of codes going off. I was crying tears of joy when I found this simple fix. Thanks for all the great tips for the newbies.
But a HOSE CAP (female) will NOT screw into the *female) hose connector on the RV. You need a PLUG w/ (courser) HOSE Thread (NOT (finer) PIPE Thread), and they are harder to find; MY Local Lowes had None in plumbing, nor in Garden, I had to get CAMCO off internet. 🙁
colleen moore says
an old school rubber plug like the one they you for oil caps for the dip stick hole as you twist the plug tightens they come in all sizes i feel that would work.
Bill Smoldt says
Those are good hacks. I use the Y splitter for all kinds of things while camping so I always have one available.
But to be on the safe side and keep dust out of the inlet, I bought 2 male plugs from an RV store that also have a short rubber strap attached. I put one on my inlet and one on the outside hose connector of my Sprinter, then used two existing screws to secure the strap. I alsways keep the plugs in while traveling and never lose them while docked.
Terry Hennessy says
Plug when not in use Also help keep bugs/ dirt out of your potable hose, tank and fittings
Ready to go camping for the week end..Ck valve pumping water all over the drive way..So glad I found your post! Thank you.
Garth Hart says
On any trailer I’ve owned they came with plugs for the city connection & the black tank sprayer. It keeps dirt & bugs out of the connector as well as ensuring a seal. Hardware stores sell a cheap version & rv parts stores sell a version with a tether. They are plactic & nothing special.
John Yellowolf says
Thanks for posting this! My motorhome is 40 years old, and has never had a problem……BUT, thanks for the info if I ever do encounter a problem!
It seems I have a different but similar problem. When hooked to city water, it seems the water is back flowing into my fresh water tank. When running off the fresh water tank, I know my water pump (sometimes) cycles on and off when not running water. I have ruled out a leak, so my next thought was a leaky check valve in the water pump. Is a bad check valve in the water pump allowing the water to back feed from the city water hookup through the water pump and into the fresh water tank?
We are having the same issue. Did you find a fix?
Terry Hennessy says
When CW fill the FW tank, the CHECK VALVE INSIDE the Water Pump is bad/ leaky; (Sometimes, can run pump w/ CW off and flush trash from checvalve, restoring proper operation, but (generally) PUMP will require new repair/ replaced. KITS generally 40% of new $$, and good DIY, if pump new enough? If 10-20-yo, go ahead and buy New PUMP.
Rick Ellis says
We also have the same issue! We’ve had our camper for about 3 years and have never put water in the holding tank, nor have we ever used the pump. Last time we camped and hooked up to the water, it began leaking out of the “Sanitize/Winterize” inlet. I fooled around with the valve handles in the wet bay and finally got it to stop, then drained the water out using the low-point drain. Not sure what the problem is though.
I had the very same issue and the service guy said I needed a new water pump. I searched online and found a post to try. 1. Disconnect city water.
2. Turn on water pump and run water through all faucets and toilet until all air has cleared the lines and then turn them off.
3. Allow the water pump to pressurize the fresh water tank. When it turns off, turn the pump off.
4. Reconnect to city water and turn water on.
I tried it and it fixed the problem, no more city water overflowing from fresh water tank. Guessing it’s all about proper pressure to engage the check valve.
Mr Mustang says
Thank you! Always good to learn new things! Will pick up plugs before next trip.✌????️
Just had a renter tell me the water was coming out of the city water connection after filling up fresh water tank and turned on water pump. Wasn’t sure what to tell him as I have always used city connection. Thanks for this info, good advice.
Jerry Heiser says
I use a y connector 1male end to city connection other male connection to black tank flush and adjustable pressure regulator connected to female connection. This way my regulator is out of sight and less chance of forgetting it.
Angela Waterford says
Thanks for informing me that I can depress the check valve spring to try to fix the problem of the check valve malfunctioning. I guess I can call someone to repair the RV for me in case I won’t be able to bring it back to its normal state. I’m suspecting that the hard water that’s flowing in my RV could be my problem, but since I’m still not sure, I could try asking around if anyone has had this experience before.
Fred Bryner says
I am having a water pressure problem, can the check valve cause low pressure when connected to the city water supply? I have a 2007 Itasca Meridian 34H, new to me Oct of 2019. Still learning the new rig. I am using an adjustable pressure regulator at the hose bib, all sinks and shower have very low flow. I tried removing the filter from the water filter cartridge but still had low flow. Not sure what to try next.
Ralph Nephew says
I have a Carriage Cameo 5th wheel and I am having a problem with my city water. When I put water pressure on the water runs and runs . Previously the water pressure would build up and then ready for use. I replaced the vacuum pressure check valve ,which did nothing. Then I called the Mfg. and discussed and was told sounds like it was working properly. But this way my dark holding tank will fill ,and I still will not have the city water system. Note using the water pump the system works properly.