Water leak? Here's how to troubleshoot it

It was getting dark in the campground in Borrego Springs, California and we were tired after an all-day drive from Tucson. After a half-hearted setup at the campsite we decided to go our for dinner in town because it seemed like too much trouble to make dinner.

Coming back from the restaurant to our comfortable Airstream and settling in for the night was a happily-anticipated moment, until Tothie asked, "Why is there water all over the floor?"

Of all the things that strike terror into an Airstreamer's heart, near the top should be finding water (or water stains) inside. This might not seem like the worst thing but water is probably the most insidious and certain killer of Airstreams.

It might be only a drip-drip-drip or it could be a flood, but it doesn't matter: water leaks of any type need to be addressed promptly. Here's what to do.

First, don't panic. Evaluate.

Your first task is to figure out what type of leak you have, either from rainwater or from the plumbing system. Here's how you can tell:

Exterior water leaks

• there must have been recent rain, snowmelt, very heavy dew, or perhaps you've just washed the exterior
• water or water stains may appear above countertop level, such as on walls, emanating from wall seams, on curtains or ceiling—as well as the floor

If you suspect an exterior water leak, check the obvious things first: were all the roof vents, fans, windows and door fully closed? If the answer isn't obvious, you'll need to embark on a more involved exploration. We'll talk about that process in a future blog.

Plumbing leaks

• leak occurs on a dry day
• leak slows or stops when the water is turned off
• water pooling on floor is usually a plumbing leak but not always
• you might hear a hissing sound (the sound of water spraying from a pressurized line)

What's probably not a leak

Water dripping from a trailer's belly pan (outside) is not a conclusive indicator. That can be from any source. Sometimes water will drip from the belly pan from a heavy dew that is running down from higher up on the exterior, and that's normal. However, all drips should be investigated.

Water dripping only from the air conditioner in the ceiling is probably not a leak at all. This can happen when the normal condensate drain for the air conditioner is plugged, or when the cup that collects the water has a crack in it. The water that should drain outside by the wheel well backs up until it drips from the air conditioner inside the trailer instead. If this is happening to you and it's not raining, turning off the a/c will (eventually) stop the drip. A good RV service center can clear the line for you.

In our Borrego Springs situation, water was pooling on the floor near the base of the refrigerator and because we had been in desert dryness for weeks, I knew immediately it was a plumbing leak. There was no hissing sound because the leak was a slow drip.

Second, mitigate the damage

If you suspect a plumbing leak, immediately turn off the water pump and/or the campground water valve. Run any faucet inside the Airstream until the water stops flowing. This removes any remaining pressure in the water lines so that the leak will stop or at least reduce to a trickle.

You should make every effort to prevent water from settling in cabinetry or on the floor, as it will eventually cause permanent stains or rotted wood if left to sit.

Third, trace the leak

This is the trickiest step, so take your time. Jumping to conclusions about the source of a leak will just get you chasing your tail. Take a few deep breaths and prepare to work methodically as you trace the water back to its source. Here are the tracing tips I follow:

1. Avoid getting zapped! Shut off the power at the campground breaker or unplug, and switch the inverter off if you think water may have reached electrical lines or electrical components. This is an essential step before you begin investigating.
2. Use a flashlight. It's indispensable when trying to isolate leaks. The light will reflect off water droplets, and illuminate the dark spaces inside cabinetry.
3. Keep a roll of paper towels handy. Quite often a piece of aluminum wall or plastic plumbing will feel wet because it is cool, and this makes it very difficult to tell is something really is leaking (or being dripped on). A small piece of paper towel touched to the surface will tell you conclusively if it is wet.
4. Look up and sideways. This may seem elementary but remember that water always goes down. If something is wet, look above it for the source. Water may also appear to run sideways along pipes, electrical wires, floors, and countertops.
5. Be aware of the Airstream's tilt. Campsites and RVs are rarely perfectly level, and the furniture and floors inside them are even less level, so the water may run in unexpected directions. Don't assume that because water is pooling under the bathroom sink that the leak is coming from there. Trace it carefully and make sure it's not running under cabinets or around the floor perimeter from some other source.
6. Open and look inside all cabinets. A common leak is from the kitchen or bathroom sink drain plumbing. The connections on the black plastic "P-trap" sometimes vibrate loose during travel. If this is the source of your leak you can easily fix it by hand-tightening the plastic rings. 
7. Look behind the access panels and drawers. Many times leaks are lurking behind one of the access panels that Airstream has put in place. Airstream designers know that eventually you'll need access to plumbing and electrical stuff inside the cabinets and beneath the trailer, so they've thoughtfully provided doors and panels that remove easily.

Not sure where these access panels are, or how to remove a drawer? I show you and explain what's behind them in the video below. In our Borrego Springs situation, our leak was behind the panel to the water pump. It was there (with the assistance of my flashlight and paper towel) that I was able to conclude that a fitting on the water pump was the source of the leak.  

Fourth, isolate or repair the leak if possible

It would be great if you could fix the problem immediately every time. But for the moment let's assume you found this leak on a camping trip and it's not convenient to haul off to an RV service center at the moment. Your goal at this point is to keep the Airstream functional without causing further damage, until you can get the problem fixed. 

P-traps under a sink can come loose during towing. 
Fix them by hand-tightening the plastic rings.

If you've found the source of a plumbing leak you can sometimes shut off only the affected part of the plumbing. Late model Airstreams usually have shut-off valves near the kitchen and bathroom plumbing. Again, they may only be accessible via an access point.

In our Borrego Springs leak adventure, the leak was a fitting on the water pump. It didn't leak visibly when we were running the pump, but the steady water pressure of the campground was just enough to get that fitting to drip. I could have used only the water pump for a while but since it was an easy fix I took care of it right away.

This is where Teflon (or "plumber's") tape comes in. It's common for a screwed-on fitting to have a slight leak that can't be resolved by tightening it more. A few turns of Teflon tape on the threads is the solution. We include a roll in our Maintenance Essentials Kit. I can't imagine going on a trip without a roll of this stuff, and have used it many times on both water and propane fittings. 

No matter the size or cause of your water leak, remember not to panic. Just deal with it step-by-step and it will be fine. A leak that is ignored over a long time can destroy your Airstream, but a leak that is addressed promptly won't have a chance to do much damage. 

And that was the case in Borrego Springs. I fixed the water leak and we were free to enjoy the rest of our trip. The crisis that had freaked me out at first was dealt with in a matter of minutes, thanks to some simple troubleshooting and a bit of tape.

Photo by Amritanshu Sikdar on Unsplash