Black Tank Question

foszoe · 07-08-2019, 06:17 AM

Just bought a used 5th wheel. My black water tank indicator registered 2/3 or full even after dumping. Rinsed out tank. took it home. I put ~33 gallons in a ~32 tank and a bunch of rid x in there to "clean" the sensors since it obviously wasn't a blockage.

Basically, I filled it until I could see water in the toilet pipe.

Saturday I moved it up the driveway to cut some trees. No issues.

Sunday I moved it back down the driveway to where i had it, and some of my Rid-X water started dripping from the middle underside of the trailer. I hooked the sewage hose up and opened it for 5-10 sec at the most and the leak stopped.

Are there overflows on black tanks or do I have a bigger issue?

**JRTJH** · 07-08-2019, 10:50 AM

There are no "overflows" in the true sense of the word. There are three openings on most black tanks. First is the 3" inlet for the toilet to dump into the tank, second is the 3" outlet with the slide valve for you to dump the contents and the only other "hole in the tank" is the vent stack which is attached to the top of the tank and normally is a 1.5" pipe.

You may have a loose vent stack that leaks when the tank is "full/overfull" or you may have a loose/leaking toilet connection that leaks when full/overfull. Those two are located on the TOP of the tank. Either of them may only leak when the tank is "full/overfull"....

The dump opening with the slide valve is at the bottom of the tank. If it were leaking, it would leak "all the time, even when 1/8 full" so chances are that's not your problem.

If it's a leaking "fitting" then it's going to leak only when the tank is full.

Another possible problem is a split or cracked tank. Occasionally a black tank will split at a seam or split in a weak area. If that's your problem, and if it's along the top of the tank, you may only see an issue when the tank is full/overfull.

Typically, black tanks are not supposed to leak, even when full. So, if you have leakage, it's coming from somewhere that's not supposed to be leaking. I'd check the vent stack to see if it's loose (turns when twisted) by accessing it from the roof. If that's not it, then a good visual inspection may give you some indication of what's leaking and where.....

foszoe · 07-09-2019, 01:12 AM

Thanks for the reply.

After further thought, I bet it was the vent. My wife noticed a distinct smell in the trailer while it was leaking. Much stronger than outside the trailer door. However, when she went in the restroom itself, it still smelled clean and fresh.

I won't have a chance to do much with it until Thursday.

hankaye · 07-09-2019, 05:11 AM

foszoe, Howdy;

One other possible leak area would be if you have a flush-out
or tank rinse fitting. That would be 1/2 way up the side of the tank.

hank

foszoe · 07-10-2019, 04:08 AM

Quote:

Originally Posted by hankaye

foszoe, Howdy;

One other possible leak area would be if you have a flush-out
or tank rinse fitting. That would be 1/2 way up the side of the tank.

hank

Not lucky enough to have one of those

Carrottop · 07-10-2019, 07:16 AM

Off topic a little but you can add a rinser for next to nothing and they work pretty good. Ours came with a black rinser only and we added one to our grey tank. We have also added them to units we owned that did not have one. Honestly it is about 1 hour work taking your time and sealing it up.

https://www.amazon.ca/Camco-40126-To...s%2C198&sr=8-1

**sourdough** · 07-10-2019, 08:15 AM

If you put 33gal. in a 32gal tank and it leaked I would almost bet it is one of the connections on the top of the trailer since it stopped after draining a small amount of water. Another thing to think about, and hopefully not the issue; just had the exact same issue with a gray tank. Turned out a seam on the top of the tank had split and would only leak water when the tank was completely full. Not a good, or cheap, situation.

wiredgeorge · 07-10-2019, 08:40 AM

Just want to point out that Rid X is a bacterial agent that is used to break down solid waste aka poop. It doesn't do much with toilet paper. Using that stuff won't remove sludge and toilet paper from your black tank pickup sensors. Once those are crusted up cleaning with a wand or one of those gizmos may not un-goo the sensors/probes. I installed Horst Miracle Probes in my trailer and it is actually pretty easy except you have to get under the trailer.

Here is a video comparing tank rinse systems:

https://www.youtube.com/watch?v=Lf4p1CpfgOs

https://www.amazon.com/Valterra-T213.../dp/B00YJIB7WE

foszoe · 07-10-2019, 08:49 AM

I was hoping the water would take care of the toilet paper possibility. I won't know until I go camping in a couple of weeks and can hit a dump station.

Kind of off my own topic. But are there public dump stations ? I just know of the ones when you pull out of a campground.

**JRTJH** · 07-10-2019, 09:02 AM

In some states the rest areas have dump stations. A few Cabela's stores have dump stations, many truck stops with "RV refill plaza's" include a dump station and some RV sales/service locations have dump stations. I'm sure there are other locations, but most are not "publically advertised" rather they're a benefit only those looking for will usually find.

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