Black tank Leak?

[Jbenn4422]

Hello,

I was flushing my Black tank when I noticed a small amount of black tank water coming from a cutout underneath the camper. Pic...

I hadn’t noticed it until I was flushing the 3rd time, it wasn’t dark water so I don’t think it was doing it before I emptied the tank and flushed. Do I have a leak or did I overfill the tank when flushing?

Also, I looked into the toilet when completely empty and I still see some water at the bottom. Is that normal? Shouldn’t it be completely empty if I look with a light?

I would really appreciate some advice.

Thank you

[Boscorelli]

That's the new "safety" feature so your black tank never overfills. You can keep filling it and filling it. If it gets overfilled, the custom, post-engineered, black tank overflow exhaust port opens up to rid the tank of excess contents. IJK
I'd say you have a hole in the tank. Yuck!

[Jbenn4422]

Thanks for the reply! I am confused, it is really an overflow or are you suggesting I do have a leak? Sorry, couldn’t tell

[Reverse_snowbird]

Originally Posted by Jbenn4422

I was flushing my Black tank when I noticed a small amount of black tank water coming from a cutout underneath the camper. Pic...

I hadn’t noticed it until I was flushing the 3rd time, it wasn’t dark water so I don’t think it was doing it before I emptied the tank and flushed. Do I have a leak or did I overfill the tank when flushing?

Also, I looked into the toilet when completely empty and I still see some water at the bottom. Is that normal? Shouldn’t it be completely empty if I look with a light?

Before you go and replace that tank, perhaps you need to do a bit more diagnosis.
How were you flushing the tank? Were you using a black tank flush or putting water down the toilet? If you were using a black tank flush, the dump valve should have been open to avoid overfilling.
Was that cutout on the trailer when you bought it?
There might be water on the bottom of the toilet depending on how the water drains. It's almost impossible to get all the water out.

[A32Deuce]

I found that when dumping and flushing my tanks before leaving, I drop the driver side/raise passenger side to get better cleaning. Doesn't take much. Lean the other way when winterizing to get most of the water out of the FW tank.

[Jbenn4422]

I was flushing the tank and had the valve closed. I thought the best way to flush it was to close it and allow the water to fill and then empty again? Is that wrong?

The cutout is on both sides, I think it’s supposed to be there.

I filled again and it did it again when the tank was full.

[dalford]

How do you know it is water from the black tank? It could be the flush connection to the black tank. You need to drop the underbelly so you can investigate the leak.

Those cut outs seem odd? Not sure of their purpose, is this a new RV or did you buy used? If it is black tank it should smell.

I always close the dump valve and set a 3 minute timer on my phone. Do not do this without a timer of some kind. It is easy to get side tracked. I fill and release until the water runs relatively clear. When you’re done flushing fill the tank with a couple of gallons of water and add what ever tank chemical you use.

Also, there is no overflow. The black tank is sealed and the only overflow is thru the roof stink pipe vent. Remember RV with Robin Williams...lol..

[Jbenn4422]

I knew it was because of the odor. I’ve never removed the underbelly, but it makes sense to do so and see what’s happening.

Thank you

[Reverse_snowbird]

Originally Posted by Jbenn4422

I was flushing the tank and had the valve closed. I thought the best way to flush it was to close it and allow the water to fill and then empty again? Is that wrong?
.

People are going to disagree with me, but the recommended procedure for using a black tank flush is to keep the sewer valve open. It's like a sprinkler system in there and keeping the valve open allows the sewage to be washed down from the top and sides.

[eye95]

Originally Posted by Reverse_snowbird

People are going to disagree with me, but the recommended procedure for using a black tank flush is to keep the sewer valve open. It's like a sprinkler system in there and keeping the valve open allows the sewage to be washed down from the top and sides.

I won’t be disagreeing with you. The idea of flushing is to hit all parts of the tank with somewhat pressurized water—including the walls and the floor. Allowing water to accumulate in the bottom would defeat that purpose.

The possibility of being careless and allowing the tank to completely fill is just one more reason to leave the valve open.

If the intent is to fill or partially fill the tank for some other cleaning purpose (say, doing the ice/rough road trick), then I wouldn’t bother with the black flush connection or a wand. I’d just put unpressurized water directly down the toilet.

[Jfkmk]

Originally Posted by eye95

I won’t be disagreeing with you. The idea of flushing is to hit all parts of the tank with somewhat pressurized water—including the walls and the floor. Allowing water to accumulate in the bottom would defeat that purpose.

The possibility of being careless and allowing the tank to completely fill is just one more reason to leave the valve open.

If the intent is to fill or partially fill the tank for some other cleaning purpose (say, doing the ice/rough road trick), then I wouldn’t bother with the black flush connection or a wand. I’d just put unpressurized water directly down the toilet.

I agree 100%. Using the flush with the valve closed is no different than simply filling using the toilet.

[TitanMike]

Originally Posted by Reverse_snowbird

People are going to disagree with me, but the recommended procedure for using a black tank flush is to keep the sewer valve open. It's like a sprinkler system in there and keeping the valve open allows the sewage to be washed down from the top and sides.

Is that why there is a large instruction label right next to the flush connection on my Trailer teling me to make sure dump valve is open before using flush.??

Funny how so many just ignore instructions and try a "better way".


One possible leak point that hasn't been mentioned is where the dump tube the toilet sits on may not be properly sealed where it enters the tank. Also, if a tank sensor is not tightened properly, creating a good seal where it enters the tank, leaking will occur.

[Thomas ho]

Originally Posted by Jbenn4422

Hello,

I was flushing my Black tank when I noticed a small amount of black tank water coming from a cutout underneath the camper. Pic...

I hadn’t noticed it until I was flushing the 3rd time, it wasn’t dark water so I don’t think it was doing it before I emptied the tank and flushed. Do I have a leak or did I overfill the tank when flushing?

Also, I looked into the toilet when completely empty and I still see some water at the bottom. Is that normal? Shouldn’t it be completely empty if I look with a light?

I would really appreciate some advice.

Thank you

I had a broken black tank part where it attached to the tank. black water spewed out top where it was attached. not good. replaced part. i dont use the flush for tank anymore.

[Scrapper]

There are several places the water could be coming from. As mentioned before a bad seal between the toilet and tank. Or a bad seal where the vent stack goes into the tank. Or you could be filling the tank so full the water is going up the vent stack then back down the side of the stack. You may be filling it to the point the water runs down the side of the stack but not enough to push it onto the roof. If this is the case then you have water inside the wall where the vent stack runs. Because of expansion/contractions rates of the different materials and the vibrations caused by roads, the vent stack is not sealed at the roof, it sits inside a larger tube which is sealed to the roof membrane. My tt also has a sticker next to the black tank flush that says to leave the dump valve open when using.

[jannjim]

I find that when flushing my black tank, if I close the valve for 5 minutes or so and then open it I see a lot more of the solids coming out rather than leaving the valve open. I repeat this 3 to 4 times until it I show pretty much only clear coming out. To make sure you don't get sidetracked and forget about the valve being closed, you can set an alarm on your phone. This is what I found works best for me.

[tramponi]

Were you able to find the cause of your problem? If so, how did you fix it? I had a similar leak this weekend when flushing my black tank so I am looking for help in figuring out what happened as it hasn't happened before.