How do I find what’s causing the water leak in my RV?

Dear Dave,
While city water is hooked up to my RV, the water starts to leak, causing the living room floor to leak. What could this be? —Jason, 2001 Tiffin Phaeton

Dear Jason,
The first thing I would check is the pressure from the city water source. If you are at a campground, typically the water source is from a well and the closer to the pump you are, the higher the water pressure. You can check the pressure with a simple screw-on pressure gauge like this one.

Most RVs are safe at 40 psi and some of the newer ones can handle 60 psi and more. But it is important to test to see what pressure your water source is at. I recommend getting a water pressure regulator that mounts permanently to the incoming hose at the campground source to set it at 40 psi automatically.

Here is one that is connected to the inline filter that I recommend, as well, although it has nothing to do with pressure.

Since your Tiffin is a 2001, I’m not sure what type of water supply lines and fittings they used back then. I believe they are PEX lines, which should be able to handle pressure up to 60 psi or more. However, the connections are the weakest link. If you just have the cheap ring clamp style, they may not be able to hold the pressure and will leak. These can work on higher pressure but need to be installed with a ratcheting tool and pressure tested. Using just a simple hand pinch does not work.

So, check the pressure and if it is over 40 psi, put on a reducer and see if that eliminates the leaks. If it does, then you can either live with a lower pressure and use a regulator all the time, or track down the connections and change them with a stronger ratcheting type connection.

What if it leaks at 40 psi or lower?

If excess pressure is not the issue, then you need to start tracing water pipes to isolate the area and ultimately the leak, which could be at a connection or in a supply line. Since it is in the living room, I would believe it is a supply line to the kitchen faucet or the ice maker. You did not provide information on what you saw in the living room so I can only assume it was wet carpet or puddles on a wood or tile floor. That should also provide some information on the direction the water is coming from. Open the cabinet doors under the sink and see if there is water on the floor. If yes, then the source of the leak is from the water supply lines going to the faucet.

Could it be the ice maker in the refrigerator?

One of the biggest oops! in winterizing is not getting the water out of the supply lines to the ice maker in the refrigerator. You can take out the filter under the sink and shut off the valve, but water is still in the line to the ice maker and inside the ice maker. When temperatures dip below freezing, water in the line and mechanism will freeze and expand enough to break and then cause a leak the next time water is reconnected in the spring. This can happen on an absorption refrigerator or a residential model. Check under the sink at the shut-off valve, at the filter, and the line up to the ice maker.

 You might also enjoy this from Dave 

How can I repair a leaking PEX water line?

Dear Dave,
What is the best and easiest way to repair a leaking water line made of PEX? And can I buy those fittings at a local hardware store? —Herb

Read Dave’s answer.

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

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