On the last night of our most recent RV trip, we noted water seeping along the floor from the interior cabinet that houses a "rats-nest" of water intake/outlet connections to and from the water pump/city water inlet etc....kind of a "water-line central" location.We turned off the water that night and I felt 100% confident that when we were home and I removed the panel in front of that site (and turned the water hookup back on to city water) I would locate a leaky connection etc that I would repair/retighten etc NOT SO! After 48 hours and repeated inspections, the compartment is bone-dry with no evidence of leaking water anywhere. I can't figure this out...any help or ideas or suggestions would be welcomed. Thanks!!

Were you using a water pressure regulator. Thinking perhaps too much pressure. You might try putting newspapers around then shaking the pipes to see if anything drips.

Yes, I was using a pressure regulator then and now.

My buddy had a hard to find leak. It ended up being a tiny staple poking the tubing from underneath. Had to run hand along all the pipes to find it.Also, if there's a vacuum breaker for the black tank rinse, it may occasionally spit water. (Mine never hase but others have reported seeing this).Finally, some outside showers have a weep hole on the back of the valve that will let a litte water go after use.

First thing I would do is switch to the water pump - even if you have even a slow leak the water pump will periodically turn on as pressure drops. If the water pump never turns on then your issue is likely related to water pressure or maybe rain etc. Doesn't help diagnose a fitting which won't handle higher pressure but will help eliminate possibilities.

Rarely does a flow water line leak intermittently- it leaks or it doesn't. I have to wonder if your water leak wasn't coming from another source, perhaps water splashed from a sink or shower.

Need help/advice finding INTERMITTENT water line leak

20 Replies

time2roll
Nomad
Sep 29, 2017
I don't like any of that flexible tubing with hose clamps for a pressurized water line.

Either PEX or get a threaded fitting and a flex line from Home Depot/Loews.

That flex line should only be used to dip into the fresh water tank and even that is questionable.
JMHO.
kabbro
Explorer
Sep 29, 2017
Ralph Cramden wrote:
By chance a Forest River brand? Forest River, and some others, have a bad habit of attaching flexible tubing to one side of pex fittings and then using pex crimp rings to clamp it. They all will leak eventually as flexible tubing should be attached to barb fittings. The solution is to use a pex removal tool to remove the crimp and replace the crimp clamp with two small hose clamps. RV plumbing is typically done on the line by pre school classes who were taking a tour of the factory that day......I think lol.

No, a Funfinder by Cruisers Rv...but yes, flexible tubing with what is think is a crimp ring.
Ralph_Cramden
Explorer II
Sep 29, 2017
By chance a Forest River brand? Forest River, and some others, have a bad habit of attaching flexible tubing to one side of pex fittings and then using pex crimp rings to clamp it. They all will leak eventually as flexible tubing should be attached to barb fittings. The solution is to use a pex removal tool to remove the crimp and replace the crimp clamp with two small hose clamps. RV plumbing is typically done on the line by pre school classes who were taking a tour of the factory that day......I think lol.
kabbro
Explorer
Sep 29, 2017
Ok, thought I had the problem fixed, but it's not...I replaced an O ring and felt fortunate that the leak was at the connection most accessible...well, now that connection is dry, but 5 hours later I found more water than ever before leaking from one of the connectors somewhere in the "rats nest",,,will have to reexplore tomorrow...and some of those connections seem inaccessible for handling for all practical reasons.

One questions: 2 respondents seemed to recommend "use the water pump." Does that mean to have the city water connection on, but also have the water pump on? (With the seperate water tank empty)? If so, what does that accomplish?

Thanks in advance.
DownTheAvenue
Explorer
Sep 24, 2017
kabbro wrote:
BINGO!! There is now water seeping out of the enclosure just like the other night. The amount of information and knowledge on this site is astonishing. Thank you!

I haven't taken the time yet to get into the "rat's nest" and determine exactly what fitting is leaking,but will attempt to do so later.

One question, if I made a new routine where I was sure to turn on the hot water faucet just as the water gets hot so as to relieve the pressure that's built up, do you think that would prevent leaks (lazy man's solution if I have trouble finding the leak in the "rat's nest")?

The pressure relief valve is doing its job, releasing water as it heats up and expands. The air pocket at the top of the inside of the heater has been compromised. Darin and refill. Better yet, just install accumulator tank.
ksg5000
Explorer
Sep 23, 2017
I suggest you find/fix the leak rather than mess around with trying to relieve hot water expansion. Further - if you have a loose pipe joint who's to say it's not going to just give way one day and if your not in the rig your neighbors are going to watch waterfall from your rig. That's one of the reasons some prefer to use water pump and some will never leave the rig until they turn off the shore water source.
time2roll
Nomad
Sep 23, 2017
Forget the new routine unless you are still enroute and cannot do the repair. But yes if you let the hot water drip you should avoid the issue temporarily.

Just find the leak and fix it, take it in, or get a mobile guy.
I also recommend a small expansion tank. All closed systems should have one.
DrewE
Explorer II
Sep 23, 2017
kabbro wrote:

One question, if I made a new routine where I was sure to turn on the hot water faucet just as the water gets hot so as to relieve the pressure that's built up, do you think that would prevent leaks (lazy man's solution if I have trouble finding the leak in the "rat's nest")?

Likely not for too long. The general trend is for leaks to get worse over time, not better. Maybe now that you have a way of reproducing it you can put some paper towels or something around the pipes and see more precisely where it's coming from.

If the leak coincides with a lot of water usage, it might also be the pipework sweating rather than actually leaking (i.e. condensation on the outside of the pipes). This is particularly true if the incoming water is cold and the interior air is moist. That it coincides with the water heater heating water rather than with water usage would seem to invalidate this idea, though.
kabbro
Explorer
Sep 23, 2017
BINGO!! There is now water seeping out of the enclosure just like the other night. The amount of information and knowledge on this site is astonishing. Thank you!

I haven't taken the time yet to get into the "rat's nest" and determine exactly what fitting is leaking,but will attempt to do so later.

One question, if I made a new routine where I was sure to turn on the hot water faucet just as the water gets hot so as to relieve the pressure that's built up, do you think that would prevent leaks (lazy man's solution if I have trouble finding the leak in the "rat's nest")?
kabbro
Explorer
Sep 23, 2017
Thanks for all the responses...appreciate them. The posts by PawPaw and time2roll might have the answers. That stimulated a memory that we had gone out to dinner, when we hooked up I had forgotten to turn on the hot water heater, did it as wife anticipating hot shower, we had not used the hot water and it wasn't too much longer when we noticed the leak....so, the scenario of hot water expanding without relief seems to fit (I hope so)...as I type, the water tank is heating up. I shall soon be checking it. Probably the rare occasion when I am hoping to see a leak....to solve the mystery.

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Need help/advice finding INTERMITTENT water line leak

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