Moisture Bathroom Cabinet

[Joe1969]

In getting ready for a trip I checked under the bathroom cabinet. The toilet paper rolls were wet, semi soaked and moldy. Weird as the tanks and lines have been dry since late December, when I drained everything. The toilet paper seems to be the only thing that is wet. I got the trailer out of storage a few days ago to start checking everything and have been running the heater all night to make sure all systems go. Temp at night between 45-50, up to 60 in the day. No condensation anywhere else in the unit. Anyone ever heard of or experienced anything like this before?

[JRTJH]

I'm not sure exactly where "under the vanity" the toilet paper rolls were located. If they were on a shelf, off the floor, then check the following:

If you have a black tank flush system or not (some years Springdale had them, some years they didn't)... If you do, there's an anti-siphon valve under the vanity. It is extremely fragile and easily damaged if it's frozen. So, look under your vanity and count the PEX tubes you see. If there are two and you do not have a black tank flush fitting on the outside wall of your trailer, that is not the source of your wet toilet paper...

On the other hand, if you have 4 PEX tubes under the vanity, then two of them are connected to that anti-siphon valve and it probably froze and leaked onto the rolls of TP and is the source of your "wetness"....

If you do not have a black tank flush system, check the P-trap carefully. It may have frozen and split if there was insufficent antifreeze in it...

The last possibility that I can think of is a loose fitting on one of the faucets. So reach up behind the sink bowl and make sure the hot and cold water lines are tight on the faucet stems.

If the toilet paper rolls were on the actual trailer floor in that vanity cabinet, then you may have a leaking shower/tub base, a water leak along the trailer sidewall or even a damaged vent pipe buried in the wall.

It may take some "serious sleuthing" to find the source of the water, but I'd put my first bet on that anti-siphon valve or the P-trap.

[Joe1969]

They were not on the floor, they were on the shelf in the vanity about 12 inches above the floor. Fan water a bit. No leaks. Removed the bottom panel so I could see what was happening on the floor, no leaks. I know what the p-trap is. Not familiar with the “anti-siphon” valve.

[Lee]

Joe,

The valve looks something like this picure.

First thing I did when I bought my RV was to remove this valve.

[Max23]

Hey Lee, what did you do, just replace it with an elbow??

[JRTJH]

Originally Posted by Joe1969

They were not on the floor, they were on the shelf in the vanity about 12 inches above the floor. Fan water a bit. No leaks. Removed the bottom panel so I could see what was happening on the floor, no leaks. I know what the p-trap is. Not familiar with the “anti-siphon” valve.

If the TP was on the shelf above floor level, then about the only way for water to get to the TP is from a "plumbing leak" (not from a water leak from outside the trailer. (Of course nothing is absolute, but you probably won't find an outside source for the water)....

Back to your "visual under the vanity"... If you count 2 PEX tubes coming up from under the trailer, those are the hot and cold faucet supply lines. You won't have an anti-siphon valve in the vanity.

If you count 4 PEX tubes coming up from under the trailer, the other 2 tubes are for the anti-siphon valve. Just follow the PEX tubes up behind the sink bowl. Two will go to the faucets, the other two are connected to that "leaking device" posted by Lee in his post above.....

[Lee]

Originally Posted by Max23

Hey Lee, what did you do, just replace it with an elbow??

Yes Sir, a brass elbow.

[Joe1969]

Originally Posted by JRTJH

If the TP was on the shelf above floor level, then about the only way for water to get to the TP is from a "plumbing leak" (not from a water leak from outside the trailer. (Of course nothing is absolute, but you probably won't find an outside source for the water)....

Back to your "visual under the vanity"... If you count 2 PEX tubes coming up from under the trailer, those are the hot and cold faucet supply lines. You won't have an anti-siphon valve in the vanity.

If you count 4 PEX tubes coming up from under the trailer, the other 2 tubes are for the anti-siphon valve. Just follow the PEX tubes up behind the sink bowl. Two will go to the faucets, the other two are connected to that "leaking device" posted by Lee in his post above.....

After a trip another surprise leak on the mid level of vanity was discovered. When running the hot and cold water though, there is no visible leak. I see the fitting you mentioned but no water leaking out of it. Note that everything is tight and there is no visible leak when running water. You are suggesting replacing that fitting?

[JRTJH]

If there is no leak from the valve, then the priority is not to replace a functional part, but to continue searching until you locate the source of the water and then repair/replace that leak. There'll be time enough later on to address a "weak spot that isn't this problem"....

[Wyldfire]

Hook up saniflush and run water and see if valve is leaking then. Also watch it as water flow is stopped because sometimes that is when the back flow preventer leaks.

[Joe1969]

Saniflush has been hooked up when I drained after the trip. There was no leak.

[{tpc}]

Are you hooked up to "City" water, or running water from the tank?

I have seen a trailer that leaked from a fitting under their bathroom sink when connected to a full hookup, but without a pressure regulator. We determined that above a certain pressure, a particular fitting would leak, and below it would not. Or at least not enough to even notice it.

Fix was to tighten the fitting, but more importantly, to always use a pressure regulator.

[Joe1969]

City water when I was checking for the leak, but with a pressure regulator on the hose. The leak happened when running from the onboard tank (boondock)

[{tpc}]

Originally Posted by Joe1969

City water when I was checking for the leak, but with a pressure regulator on the hose. The leak happened when running from the onboard tank (boondock)

Well that throws my theory out the window. Maybe if the pump output was very close, and the pressure was higher to a nearby fitting, but I don't think the onboard pumps usually have that type of pressure.

[Joe1969]

Originally Posted by {tpc}

Well that throws my theory out the window. Maybe if the pump output was very close, and the pressure was higher to a nearby fitting, but I don't think the onboard pumps usually have that type of pressure.

I would include a few photos but can’t get the forum to accept pic uploads, just links to photos.

[MattE303]

Originally Posted by Joe1969

I would include a few photos but can’t get the forum to accept pic uploads, just links to photos.

It's not very intuitive, but use the "Attachments" tool (the paperclip) to upload photos, not the "Insert Image" tool.

[travelin texans]

Originally Posted by Joe1969

City water when I was checking for the leak, but with a pressure regulator on the hose. The leak happened when running from the onboard tank (boondock)

Just FYI! This is a regulator, what you need to be using.


This is NOT a regulator, it's a restrictor! It's not safe to use on high pressure water sources.

[Joe1969]

Originally Posted by Lee

Joe,

The valve looks something like this picure.

First thing I did when I bought my RV was to remove this valve.

I believe I found the issue. That fitting under the sink seems to be part of the sani flush system. When I turn the water on the sani flush a burst of water, maybe 3 ounces, seems to burst out of that valve and into the vanity. Should I just replace that valve do you think?

[chuckster57]

You can replace it with a much better quality one from the big box hardware store, or you could eliminate it and add an anti siphon valve at the hose connection.

In any case it should NOT be removed and nothing installed.

[Joe1969]

As I am a beginner, can you recommend one specifically that you would use?