Wednesday, January 19, 2022


Ask Dave: Faucets don’t work with pump but do with city water. Why?

Dave Solberg 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. Today he discusses a water pump on an RV.

Dear Dave,
My RV’s water pump fails to provide water to the bathroom and kitchen sinks. The pump won’t start but water flows fine for the shower and toilet and I hear the pump running. However, all faucets and the toilet perform well when city water is connected. What gives? —Karl

Dear Karl,
The first thing I would suggest is to get a plumbing schematic, if possible. You did not give the make, model and year, but I do know Winnebago has models available online. This is a sample of a page for the plumbing schematic of a 2016 Brave and the water pump.

Notice there are a couple of shut-off valves in-line with the pump in this artwork. Most schematics will not be this detailed but should point out shut-off valves or low-point valves.

Typically, the supply line from the city water comes in and the back pressure going to the outlet side of the water pump keeps the pump from running. There should be a “T” in the line that allows water to come out of the pump as the pressure is released when a faucet is opened or the toilet flushed. Here is another screenshot of a water pump assembly in a Winnebago travel trailer.

Notice in both diagrams there are several shut-off valves and what appear to be diverter valves. Typically you do not see shut-off valves coming off the water pump to individual faucets. However, I have learned to never say never in the RV world! I would suspect there is a valve somewhere between the pump and the faucets or it could even be a kink in tubing.

However, it is quite often that the faucet works on the city and not on the water pump. Start tracing the lines off the water pump and you might be able to find a valve. You might need to remove a panel or cover or even pull a false floor out of a cabinet/wardrobe. One model I took out on a training run had drain valves located underneath the wardrobe closet. The floor was stapled to the frame and I had to tear it out to shut them off. Water was pouring out the bottom when I tried to fill the fresh water tank. By trial and error, I found the valves. Not too uncommon during manufacturing.

One last item to check is the aerator on the end of the faucet. If it’s got calcium and lime buildup, the pressure of the pump may not be enough to allow water flow and the city water does. Never say never!

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1 month ago

First thing to check is the in-line small filter for your pump. I carry a replacement filter. When this happens, I put on the replacement filter and clean the filter and use it next time around. This usually happens when I’m boondockimg, therefore the reason for the spare filter.

1 month ago

The final answer was my first guess. Clogged aerator

James B
1 month ago

This is WHY I asked for schematics for a Bighorn 39RK Traveler, from the dealer and Bighorn. BOTH said NO!

Dick and Sandy near Buffalo, NY
1 month ago
Reply to  James B

James, Go to the manufacturers web site for your RV. Find Customer Service or ask for a Customer Relations Manager. Dealers don’t go the extra mile to help but the manufacturer should. Hope you find what you need. HAPPY THANKSGIVING stay safe, stay well

James B
1 month ago

Thanks for the info line. Happy Thanksgiving to you Dick & Sandy