Black tank filling by itself?

[96 Wideglide]

I find it hard to believe 'any' manufacturer would drain the washing machine into the black tank !!

[KSagal]

I think you have a sneak pooper!

Have you tried a security camera, to see if ... Nevermind.


I agree with the idea of removing the land source of water. This tank is filling fast enough that the on board system will show you that it is working, if that is the problem.

One thing that you may try is to turn off the toilet valve, and see if it happens.

Sinks, shower and washer will all need you to turn a valve to drain, not so much with the toilet if electric.

Good luck.

[Tha_Rooster]

Originally Posted by mrt_1111

Do you have one of those tank flush devices?

Does your tank cleaner run off of a separate hose or built in the plumbing?

[TonyMac]

Originally Posted by KSagal

I think you have a sneak pooper!

Have you tried a security camera, to see if ... Nevermind.

Oh No, you caught me. I like your toilet paper, what brand is it?

I really want to know the answer to this mystery. I'd shut off all water to the coach. If you're filling a 48 gallon black tank in 24 hours, that's 2 gallons per hour is it's a steady drain, or a quart every 15 minutes. It's not the sink! That's most of a 55 gallon barrel in a day. You got a few sneak poopers.

And I thought I was the only one.......

[loisjop]

This is just a WAG, but it is fairly common for the fresh water tank to fill on its own, bad check valve in the pump etc. I'm thinking there's a good possibility the black and fresh water sensors are crossed and your system thinks it's black tank reading when it's actually fresh water tank.
I guess it would be easy enough to see though dump the black tank and see if reading goes to zero. I can't imagine there's anything that would fill the black tank that fast.

On rereading looks like you did dump the black tank and it read zero. So much for my theory.

[Tytlfamily]

Hello guys, no sneak poopers that I know of! I've been away from the coach two days, and going on what my wife has been telling me. Today, with very moderate use, the blank tank has been showing fairly steady all day.....about 1/4 .....this is a new 2014 coach we just bought, so it's been sitting on the dealer lot a few years.....wondering now if it just needed to be used.....water in the tanks, seals re expanded....a few good dumps...and so on. My first order on business tomorrow is a good flushing of the black tank.....i will go from there. If the sensors were a little dirty, hopefully a good flush will get everything going