Fresh Water tank leaks

[Grand Master IceMan]

Hello again,
...yes, I'm the one who just had to replace my bathroom sink.
However, since I had to use my Fresh Water tank while that was broken, I also discovered it has a bad leak! A full tank will completely drain in a couple of hours on it's won.
And, of course, I can see it coming out the bottom.

Supposedly, I had this fixed last year. I rarely use it, but sometimes I need to. I plan to call the same Mobile RV Service as last year to let them know.

But before I do, do any of you have any ideas of what may be causing this or what the best solution might be?
In fact, I'm thinking they replaced the entire tank last year with a new one..?

[Soundsailor]

Hello again,
...yes, I'm the one who just had to replace my bathroom sink.
However, since I had to use my Fresh Water tank while that was broken, I also discovered it has a bad leak! A full tank will completely drain in a couple of hours on it's won.
And, of course, I can see it coming out the bottom.

Supposedly, I had this fixed last year. I rarely use it, but sometimes I need to. I plan to call the same Mobile RV Service as last year to let them know.

But before I do, do any of you have any ideas of what may be causing this or what the best solution might be?
In fact, I'm thinking they replaced the entire tank last year with a new one..?

When it rains it pours (sorry couldn't help myself). Could there be a bad connection in the plumbing, it doesn't seem likely that two tanks could fail.

[Grand Master IceMan]

hmmm I bet you're right!
...and also because it did NOT leak after it was first installed; only now is that happening.
Perhaps a hose or pipe came loose or broke somehow?

[Fsalmy]

hmmm I bet you're right!
...and also because it did NOT leak after it was first installed; only now is that happening.
Perhaps a hose or pipe came loose or broke somehow?

Is the water draining from the white drain valve or seeping around the coroplast?

[Grand Master IceMan]

Hard to tell because it seems to be coming from all over
...sorry, I don't know what coroplast is.

[geotex1]

Hard to tell because it seems to be coming from all over
...sorry, I don't know what coroplast is.

Coroplast is the underbelly material.

Call the repair folks. If you've not been using it, perhaps just a fitting. If the tank overflow is blocked in any way, you can burst a tank on filling. Believe it or not, I know a new-to who burst his OE tank after following advice of forums to put a valve on the overflow so water doesn't siphon out during travel. Unfortunately, didn't understand he had to open the valve to fill the tank. Took his valve off when it went in to dealer for a new tank. 9 weeks later gets it home, puts valve on, goes to fill up tank and split it wide open in his driveway!

[Fsalmy]

Hard to tell because it seems to be coming from all over
...sorry, I don't know what coroplast is.

Coroplast is the plastic corrugated sheets that cover the underbelly.

Sounds like the coroplast will have to be dropped to determine where and what is leaking, but since you stated it drains on its own in a couple of hours, I'd start with inspecting the white drain valve fitting because it is the lowest point on your tank. You can check that out, at least to some degree, without dropping the coroplast. Does it seal completely? Does the handle move freely? Is the fitting loose?

Hope you're in a warm climate in case you get an unintended shower. You could always leave the unintended showers to a mobile tech, though.

Edit: and what @geotex1 said.