RV’s dining area floor is damp. Could it be the drain? What to do?

Dear Dave, 
The edge of our dining area has been getting damp. I think it has something to do with the sink drainage. What to do? —Rose, 2011 Chateau Citation

Dear Rose,
I would start by placing some colored paper like red rosin paper used for floor covering in construction or painting, or even cardboard, under the sink area you suspect a leak. Water dripping on the paper will darken it and help identify where it is coming from. If your dining area has carpet, that will wick and sometimes give a false sense of where the leak is coming from.

RV plumbing leaks are common

It is not uncommon for plumbing in an RV to develop a leak as it gets bounced around pretty good to and from the campground. Then we also shove things under the sink and that can also loosen the “P” trap and other plumbing.

If you do identify the area, check the drainpipe fitting and the top and bottom threaded fitting of the “P” trap. Keep in mind that a leak at the drain pipe will flow down and leak at the lowest point. So where the water is dripping might not be the actual leaking spot.

It is very difficult to keep the plastic fittings tight on RV plumbing, so a little tip is to wrap any connection with silicone tape such as “Rescue Tape”.

Here is a photo of the “Trailer From Hell” that we wrapped the drain pipe and eventually every joint as it just would not stay tight. You can get rescue tape on Amazon here.

As I stated earlier, a leak doesn’t always drip below the entry point and your damp floor could be from an exterior leak of the roof to sidewall joint, front cap, or even window. The water penetrates and can flow through hollow framework or even a sidewall and come out at the floor, so it is sometimes difficult to find the gremlin.

Check all your roof and sidewall seals and make sure there are no gaps or pinholes that moisture can penetrate.

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Dave Solberg is a leading expert in the RV industry and the author of the “RV Handbook.”

Read more from Dave here. 

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