RV’s water pump doesn’t pump


Dear Gary,
I’m having my RV winterized for storage. The dealer called to tell me that the pump doesn’t work. It is located underneath the fresh water holding tank. They unhooked it from the tank to pump antifreeze into the pipes and it wouldn’t work. Is it a suction pump? Does it have to be connected to the holding tank to work? —Walter

Dear Walter,
RV's water pump doesn't pumpIt’s not uncommon to disconnect the water pump from the fresh water tank in order to pump the RV antifreeze through the system. A better setup, however, would be a tee in the suction line between the pump and the fresh tank with a dedicated shut-off valve just for the winterizing purpose. This is easily added.

RV water pumps are self-priming pumps, but on rare occasions they can develop an air blockage. When they told you the pump didn’t work, did they mean it runs but does not pump? Or does the motor not run at all? If it does not run at all, it is probably a 12-volt DC electrical issue and not a priming problem. But if the power and ground connection is correct, it then may be necessary to “prime” the pump by pouring water directly into the inlet hose connected to the pump.

RV water pumps do “suck” the water out of the fresh water tank and they also “push” the water through the rest of the fresh water system whenever there is a demand for water. If an air bubble exists on either side of the pump, suction or downstream, it could cause a water flow issue. Further investigation may be in order here.gary-736

Read more from Gary Bunzer at the RVdoctor.com. See Gary’s videos about RV repair and maintenance.


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Dave Telenko

Oh boy Gary I really, really love your new outfit. LOL How about a nice quote like “The Doctor Is In”

James O. Springate

What they probably meant is that it wouldn’t suck antifreeze out of the bottle. Mine wouldn’t either, and I had the complete setup. I replaced the pump and everything. I have been winterizing it by first draining the system with the low point drain, then using air to blow out the pipes. I recently bought a transfer pump off Amazon that I am hoping to run antifreeze via the outside fresh water inlet.


I would be a bit concerned that the “dealer” couldn’t diagnose a normally simple issue like that before contacting the customer…