Fresh Water Pump In Our Toy Hauler Will Not Stay Primed and Pump Water

by Jason
(Prince George,BC, Canada)

Note From RVing Al: This question is in reference to a 2006 Desert Fox Toy Hauler


I purchased this Toyahuler second hand. I was having trouble priming the system so I made sure it wasn't the water level sensor indicating full causing the problem. This was done by completely filling the tank (did not take long) it was almost full. The system primed and pressurized right away.

Good Sam Extended Service Plan is mechanical breakdown insurance for your RV, 5th Wheel, Trailer, and Tow Vehicle! FREE Quote

We use it on the weekend and it worked fine. Until the last day when we were leaving. We had not used it much. Mainly just to wash dishes. When we were about to leave I was checking things over and after turning the pump off I tried re-starting and priming. Not much success. It has maybe primed once since.

I have not topped up the tank since because I know it is almost full. I've since checked the filter, checked for leaks, and opened the pump up and it looks good.

Here's a clue, there is a valve and hose for draining the system (intake side of the pump). I opened it's valve and blew on the hose expecting to feel and hear the air bubbles back in the tank. But nothing, I was able to keep blowing back with some resistance.

Hard to get at the tank. I've opened things up so that I can see the connection on the top of the tank but it is hard, if not almost impossible to access the hose clamp.

Ever heard of the pick-up inside the tank breaking off?

Any ideas? Any fixes?

Many thanks in advance.


Over 1,500,000 successful roadside rescues—Good Sam RV Emergency Road Service

ANSWER: Hi Jason based on your description we have pretty much isolated the problem to be from the suction side of your RV's Fresh Water Pump to
the Fresh Water Holding Tank. Also based on your description I don't think that the problem is in the fresh water tank itself. Below I have listed some areas to check and recheck.

1. Even though you say that you have checked the water line going from the pump to the fresh water tank, you should do a closer inspection. Any loose connection or small crack in that water line could cause your pump to lose its prime and depending on the size of crack or leak the pump may not self-prime.

That hard to get to hose clamp on the Fresh Water Holding Tank could be a prime suspect in allowing air into the system.

2. Closely inspect the water pump for any signs of cracks or areas that might be allowing air to get into the system. Since you live in Canada, there is a good chance that the fresh water line or the pump itself could have frozen if they were not properly winterized. Water freezing in a fresh water pump can irreparably damage it and the damage is not always visible to the naked eye.

The fact that you took the pump apart could also be part of the problem if it was not properly reassembled.

3. You also need to determine if your Toy Hauler is equipped with a Fresh Water Pump Bypass valve. If it is check the valve to make sure that it is not partially closed. It should be fully in position to allow water to flow directly to the water pump as this could cause the symptoms your are experiencing.

I hope this helps.

Join the Good Sam Club Today! Discounts, Tips, Tools & Much More!

Happy RVing

RVing Al

Do you have any suggestions or comments on this topic? You can add them to this page by clicking on the "Click Here To Post Comments" link located near the bottom of this page.

Click here to post comments

Return to Ask an RV Question.