Water leaking into fresh water tank when hooked up to city water

Abn1SG

Advanced Member
Joined
May 13, 2017
Posts
64
Location
Georgia
I have water slowly filling up my fresh water tank when I am hooked up to the city water. I have done some research, and it appears that it could be one of these 2 things:

Water valve selector from normal to fill has gone bad or check valve in water pump has failed.

Question is if it's the exterior water compartment water valve, how do I get to it to replace it since it's enclosed ?

Thanks.

2015 Winnebago Era
 
Last edited:
Don't hook up to city water. I never do. Just an opinion. I do plug into shore power and am happy to have the hydrant right there to fill the tank when I need it or before leaving.

It makes life easier on the water pump as it doesn't have to block city water pressure.
Harry 2003 C180P
 
.

Do you use a pressure regulator?


What do you mean by city water?
Do you mean at home? or at the campsite?

Don't trust the water pressure at the campsite.
Some of them can be quite high.
Also, they can vary -- when a few people turn on the water at the same time, the pressure drops. When they all shut off at the same time, the pressure shoots up, the sudden rise can damage your plumbing.

There is a reason RV shops sell water pressure regulators


:-D
 
Don't hook up to city water. I never do. Just an opinion. I do plug into shore power and am happy to have the hydrant right there to fill the tank when I need it or before leaving.

It makes life easier on the water pump as it doesn't have to block city water pressure.
Harry 2003 C180P

I guess doing this would rectify the issue and I won't have to worry about finding out how to replace the water valve nor the water pump check valve. :D
 
.

Do you use a pressure regulator?


What do you mean by city water?
Do you mean at home? or at the campsite?

Don't trust the water pressure at the campsite.
Some of them can be quite high.
Also, they can vary -- when a few people turn on the water at the same time, the pressure drops. When they all shut off at the same time, the pressure shoots up, the sudden rise can damage your plumbing.

There is a reason RV shops sell water pressure regulators


:-D

Yes I use a gauge water pressure regulator; by city water, I mean any water hookup, both at home and at a campground.
 
I have used the city water hose hook up, but I now fill my tank thru the front door water access...no more bending, etc. When we pull out, I only have 5-10 gallons, to keep the weight down, but have water at the same time. Ron
 
If you had a check valve in the pump fail, the tank would fill at the same rate it fills from the street water connection.

More than likely you've got a piece of grit/sand/plastic/calcium stuck in the water pump check valve, holding it open just enough for water to seep back through it under pressure. The easiest thing to do is just to use the pump on the fresh water tank for a couple of days to flush whatever is holding it open out of the valve. Then hook up to the city water supply and see if your problem has resolved. If not, you can take both lines off the water pump, remove it, and flush it with fresh water, and then re-install it. That takes care of it in 99% of cases.
 
If you had a check valve in the pump fail, the tank would fill at the same rate it fills from the street water connection.

More than likely you've got a piece of grit/sand/plastic/calcium stuck in the water pump check valve, holding it open just enough for water to seep back through it under pressure. The easiest thing to do is just to use the pump on the fresh water tank for a couple of days to flush whatever is holding it open out of the valve. Then hook up to the city water supply and see if your problem has resolved. If not, you can take both lines off the water pump, remove it, and flush it with fresh water, and then re-install it. That takes care of it in 99% of cases.

Appreciate the info; the fresh water tank filled up at a slow rate when it was hooked up to the main water supply so it appears what you're saying is what's happening. We did just use the water pump a couple a weeks ago the whole weekend so hopefully that has cleared the water pump's check valve. If not, I have read where some have put an in line check valve on the output side of the water pump's water line to fix and avoid this problem from happening again and that is probably what I will do next.

2015 Winnebago? Are you under warranty?

No it's not.
 
Appreciate the info; the fresh water tank filled up at a slow rate when it was hooked up to the main water supply so it appears what you're saying is what's happening. We did just use the water pump a couple a weeks ago the whole weekend so hopefully that has cleared the water pump's check valve. If not, I have read where some have put an in line check valve on the output side of the water pump's water line to fix and avoid this problem from happening again and that is probably what I will do next.

A new water pump is $80 from Amazon.

The check valve in the pump is a very simple device that opens when water flows through the pump from the tank and closes with back pressure from the city line.

If the valve is still allowing a back feed after you ran it, before you install another check valve, just pull the pump out and rinse the pump head thoroughly to dislodge whatever foreign material is there. Likely that's all that it'll need. They're very easy to remove, usually with just a couple of mounting screws, and unscrewing the plumbing lines. Hopefully they put it in a place you can get to easily.
 
A new water pump is $80 from Amazon.

The check valve in the pump is a very simple device that opens when water flows through the pump from the tank and closes with back pressure from the city line.

If the valve is still allowing a back feed after you ran it, before you install another check valve, just pull the pump out and rinse the pump head thoroughly to dislodge whatever foreign material is there. Likely that's all that it'll need. They're very easy to remove, usually with just a couple of mounting screws, and unscrewing the plumbing lines. Hopefully they put it in a place you can get to easily.

Thanks, might try this first if water pump is accessible.
 
I can pretty much guarantee you it'll be easier to do that than it will be to try to install a second check-valve in the plumbing right before the pump. There's a 99.9% chance that your coach is plumbed with Pex and you're going to jump through some hoops to re-plumb it to accommodate an external check valve.
 
It took many days using the water pump but it looks like it finally back to where water is not going into the fresh water tank when the water hose is hooked up to the water outlet. Appreciate the recommendations and the fix to this issue. Will continue to use the water pump more frequently for sure.
 

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