Need help diagnosing interior water leak

[ARF]

We have a 2017 27FB Twin Flying Cloud. Picked it up in July.

Just started getting a water leak from the inside front corner of the bathroom out into the the floor between the beds. Here is what I have noticed so far:

• Water is between the toilet and the inside back wall of bathroom and outside that same corner. Seems to be running under that corner.
• Not sure if the water is coming from the toilet or from the corner of the bathroom. This is the corner with a diagonal piece of molding which I believe is a chaseway for an exhaust stack.
• As of now, it seems the leak occurs when we are on city water, not pump and fresh tank.
• Had a repair recently on the underside and the dealer had left the tank valves open. I closed the two brass stopcocks. Not sure if there is another tank valve I should have closed or left open
• Water seems to be clean, fresh water - not waste water from the toilet.

I welcome any suggestions and help with diagnosing this issue.

Thanks, Allen

[dznf0g]

Where is your city water inlet in relationship to where you see the water inside?

[paiceman]

Guessing here that you have a leak where the fresh water enters to toilet or the sink supply lines, either cold or hot. I would start with the toilet and turn the water connection off which should be just behind the toilet itself. If the leak stops, you know you've got a problem with the toilet. If not I'd check all around the sink area under the sink etc. Toilet supply leaks are not unheard of.

Bud

[ARF]

Bathroom is on passenger side, city water on driver side.

[ARF]

Originally Posted by paiceman

Guessing here that you have a leak where the fresh water enters to toilet or the sink supply lines, either cold or hot. I would start with the toilet and turn the water connection off which should be just behind the toilet itself. If the leak stops, you know you've got a problem with the toilet. If not I'd check all around the sink area under the sink etc. Toilet supply leaks are not unheard of.

Bud

OK - I will check this out.

Curious where the weak link is in the fresh water lines should the water supply be too strong. I know the newer Airstreams have pressure regulators, but perhaps the campground we are at now has too much pressure.

[SSquared]

Originally Posted by ARF

Curious where the weak link is in the fresh water lines should the water supply be too strong. I know the newer Airstreams have pressure regulators, but perhaps the campground we are at now has too much pressure.

We have had four plumbing leaks (that we know about) in our 2013 25FB Flying Cloud Twin.

1) toilet shut-off valve. Water started leaking out of the stem of the valve after about a year. In our trailer this valve is just a few inches from the toilet. It was a slow leak. I replaced the valve with a metal ball valve from a hardware store. This is a candidate for your leak. Feel the valve itself to see if it is wet.

2) Mystery toilet water spray. One time we found fine water droplets on the wall behind the toilet. It has to have been a case of water spraying out under pressure from one of the joints or fittings. We replaced the valve in the toilet and the problem has not happened again. You leak sounds different.

3) City water inlet. The fixture supplied by Airstream is a plastic assembly that can start to leak after a while. We had to replace ours after 3 1/2 years. Note that it can leak whether you are connected to city water, or using the pump. Since this is on the opposite side of the trailer from your leak, it is not a likely candidate.

4) Kitchen sink drain. About 20 minutes after finding the city water inlet fixture leaking, we took something out from the cabinet under the kitchen sink and discovered water right under the drain. It was leaking at the junction between the sink bowl and the drain pipe. This is also not a likely candidate for your problem. But do check your bathroom sink drain.....

In my trailer, the supply line for the toilet originates under the bathroom sink, goes into the space under the curb side bed (next to the water heater), heads toward the center of the trailer a foot or so, then goes through the wall into the bathroom near the toilet. The curb side bed has an opening near the bathroom that lets you reach the water heater winterizing valve (lift the foot of the mattress). You can look in there for a leak, and to see how far the water is traveling. Feel all of the pipes and connections you can reach (both for the water heater and the toilet supply) to identify any leaking joints.

Good luck finding your leak.

[Caffeinated]

Tighten/check all the connections you can find between the toilet and the wall. I had a intermittent leak there and that fixed it.

Mike

[mojo]

Ditto...had the same leak and tightened the connections to the toilet and it went away.

[ShinyPete]

ARF-

I'll also add to the excellent suggestions above. We have a '14 version of your same coach, and have found several slow/drip type leaks over the years at various locations. What has really cured several of ours is carefully tightening every water line connection at every fixture in the coach. I would bet due to the layout of your coach that your leak is coming from the toilet supply.

I once thought I had a leaking pex connector/crimp ring thingy, but it was really just a loose spin-on connector. The water line connections throughout your coach look like threaded water hose connections, most with finger tabs on them. Just snug them up, which reseats/tightens the rubber washer inside the threaded end piece. And while your at it, also finger snug all the drain line connections as well at sinks and shower. We just last weekend had a drip under the kitchen sink that was cured with snugging the drain line connections. I believe all of these connections loosen with travel due to vibration/motion/whatever, and will show a leak now and then (and usually for us it's when we're on city water due to higher pressure).

If this doesn't cure the problem, then do follow the advice above and start replacing anything you can near the toilet (or have a dealer do it as you have a new coach) until it is cured. Hope this helps.

[fran&frank]

An old plumber's trick is to wipe all the fittings and joints with toilet tissue, moisture will show up on it that you may not be able to otherwise see or feel.--Frank

[GandW]

I had the same sounding leak. All I had to do was tighten the connection from the toilet to the floor flange. My guess is that on a new trailer, after bouncing around a little, the mate becomes a hair loose. Mine only did it sometimes, probably depending on how the levelers are twisting the trailer. i actually found the problem and fix on the Dometic site.

[pmclemore]

If you have a porcelain toilet, that could be your problem. Mine does not have a lip on the inside of the bowl, which allows water to slosh out when I am traveling. The only thing that works is to keep much less water in the bowl - only an inch or so.

Pat

[ARF]

Appreciate all of the helpful experience share.

We were dry camping for several days and did not have a problem. Back at a campground with water supply. As of now, no leaks. I think the problem may have been a very strong water supply that overpowered the regulator built into the Airstream.

I will keep an eye out for leaks in the future. Now I know how to spot them (like the toilet paper trick) and how to fix them (tighten the connection or toilet bolts).

Thanks again, Allen

[LBOskiBear]

Originally Posted by GandW

I had the same sounding leak. All I had to do was tighten the connection from the toilet to the floor flange. My guess is that on a new trailer, after bouncing around a little, the mate becomes a hair loose. Mine only did it sometimes, probably depending on how the levelers are twisting the trailer. i actually found the problem and fix on the Dometic site.

Same here - first trip on my "new to me" 27FB. I noticed the carpet in the bedroom was damp and found a slow leak from behind the toilet. Because of the angle of the trailer at the time, the water leaked to the bedroom and not in the bathroom.

I hand tightened all the connections behind the toilet and it's fine now. I do check each trip just to make sure.

That "wall" between the bathroom and the bedroom is quite thin. In fact, at night, if someone is in the bathroom, I can easily see light spilling out between the wall and the interior wall of the AS.

[h70man]

A very difinited way to locate a water leak is to pressurize your water system. Simply screw a pressure adapter into your city water inlet. With the aid of a helper apply air pressure ( do not exceed 60psi) listen for air leaking or look for spraying water.
Good luck! ☔️️