Fresh Water tank leak

[BasilHayden]

I want to put this problem to the flock collective brains for suggestions.

2019 Redhawk 29xk

Fresh water tank has recently developed a slow leak, a drop about every 10 seconds or so. Doesn't matter how much is in the tank.

Our camping style is usually hooked to city water, only using the FW tank when travelling or transition from road to camp and back.
We don't carry more than 1/3 or so of water, just enough to flush toilets, wash a dish, etc.

The rig has been sitting now in it's level asphalt parking spot for about two weeks with 10 or so gallons in the tank. The leak has continued steady enough to leave a small wet spot on the ground. It sets about 1 degree off level to the passenger side so the drip occurs on that side.

The tank is just forward of the rear axle in the center of the floor.

Inspection shows no external damage and the sides of the tank are not wet as far as I can tell. The drain is clearly visible as it exits the tank and seems clean and dry.

The leak accumulates around the front (the cab side) tank support and is wet all the way across with the most accumulation toward the passenger side, which makes sense given the 1 degree lean to that side.

My suspicion is that the support has a defect, sharp edge, or something that has rubbed a hole in the tank, but the tank material is pretty thick and would take a while to rub through.

It's pretty tight quarters but I can lift the tank about 1/2" off the support but side to side movement is not happening.

Next step is to empty the tank and try to lift it enough to completely dry the support, then work some blue shop towels between the support and tank then put some water in. The light blue towel will turn dark blue pretty quickly when it gets wet.

Immediately above the tank inside the coach is the water heater and kitchen sink. Inspection shows no leaks, standing water, or any other evidence of a problem. The water pump and fill lines work as expected.

Anyone had an issue like this?
Suggestions appreciated.

Worse case at this point if I cannot find the source and it continues slowly I can live with it.

Thanks.

[Jagiven]

I think you are on the right track

I like to use Toilet paper to trace difficult water leaks. TP, when it dries changes texture, so you can tell later, even if the water is all gone. I apply it loosely, and use a little scotch tape when needed to hold it in place.

Water plays funny games. It may not be the water tank. Parents had a water leak for years. Only happened once in a while only sometimes when it rained. It was finally tracked down to the TV antenna. It leaked through the lubrication hole. Dripped onto the coax cable. then followed the cable to a wooden ceiling frame the coax touched. If the stars where aligned. The water transferred to the structure, traversed to the other side of the TT, and dripped on the ceiling. Took years to find the leak. It only did it once in a while.

So I use TP, to also eliminate possible other sources.

Check your pipe connections to and from the tank, including the drains, pump pickup, vents, etc.

With water in the FW tank, have you turned on the pump and let it pressurize the system and let it sit? If the pump cycles for no reason there is a plumbing leak.

[BasilHayden]

Difficult to check the input/output line entry points as they are all on top of the tank and unreachable from the bottom, but the sides of the tank are dry so I doubt anything is leaking and running down.

That's part of the reason I let it sit unused these couple weeks to mitigate possible problem sources.

Yes, water acts funny, seeking the path of least resistance. Roof leaks are especially aggravating.

The water pump acts normally, no cycling unless being used. I usually shut the water off at the spigot if we leave for any length of time and the water pressure gauge is right where it was when we left.

I'm really hoping this does not get worse. If not I'll live with it. There could be worse problems to have I think.

[Jagiven]

My FW pickup, is tied to the outside of the bottom edge of the tank. Plumbed in with a tee, to the low point drain.

[BasilHayden]

Originally Posted by Jagiven

My FW pickup, is tied to the outside of the bottom edge of the tank. Plumbed in with a tee, to the low point drain.

Yes you were correct, crawling into a better position I can see both the drain (LS) and pickup (RS).


The towel trick worked. The leak is definitely coming from the opposite side of the drain. Lifting the tank I can't feel anything along the edge that might be suspicious.
Time to get the endoscope out to get a better look.

[pconroy]

Originally Posted by BasilHayden

Time to get the endoscope out to get a better look.

On the glass-half-full front, any problem that means I get to buy a New Tool makes things a bit easier to swallow.

[Jagiven]

Originally Posted by BasilHayden

Yes you were correct, crawling into a better position I can see both the drain (LS) and pickup (RS).


The towel trick worked. The leak is definitely coming from the opposite side of the drain. Lifting the tank I can't feel anything along the edge that might be suspicious.

I know you said the leak is coming from the opposite side, but water sometimes follows where routes. I see you have a few thumb screws on the pipe connections, Have you tried tightening them up? I've had to do that a couple times over the years in other areas of the TT. As I recall there is a hose washer on the fitting.