Just got back from second trip, departed Friday afternoon, black tank empty by Saturday evening black tank is full and toilet backed up. Black tank is 37 gallons, had to use portable dump tanks to empty which sucked BTW. 9PM last night black tank is empty by 8AM this morning black tank 2/3 full. Toilet is gravity discharge Sealand toilet model 110. I did notice toilet does not seal after flushing and bowl will be dry shortly after using. My thought is toilet is running slowly and filling black tank, that is the only explanation I can come up with that tank would be 2/3 filled in 12 hours. I do not hear water running into tank but this {in my mind} could be the only reason. Anyone had this happen or possibly have a different thought on my situation? Any help would be great, thanks in advance. Trailer is 08 Keystone Cougar 300

Are you relying on the electronic level gauge to tell you how full the tank is? If so, ignore the gauge. They are not accurate, specifically the black tank. As soon as TP touches one of the gauge sensors, it closes the circuit and tells you it's full. I have a 37 gal black tank and can go about one week with 4 people before I need to dump, and we use it a lot. If your toilet pipe is clogged, you likely have the well known poo pyramid forming at the bottom. This is generally caused by not having enough liquid in the tank to start. After dumping I always add about 3 gals of clean water before using the toilet. Today's holding tanks are only abt 6 inches high and very wide. Water is need to disperse the solids so pile doesn't Form on the bottom

Last night gauge was reading full and toilet was about an inch from over flowing. 3 trips to dump station with portable dump cart so I'm fairly certain it was full. I know it was empty last night, visually and gauge was reading empty as well. This morning 2/3 full, toilet was used 4 times in 12 hours. So water is going into tank from someplace

Turn on the water pump. If the toilet is leaking, you should hear the pump cycling on and off. Also, after flushing, you should pull up on the foot lever in order to help seat the seal.

Is it possible that something else (like the shower or bathroom sink) is also plumbed into the black tank? Certainly easy to check if you have a clear extension on your sewer pipe.

pulling up on lever fills my bowl and after a few minutes water has drained

Toilet/Black tank issue | Good Sam Community

13 Replies

RJsfishin
Explorer
Aug 03, 2015
Mark Heron wrote:
RJ's I was hooked up to city water, the campground did not have sewer hook up.My black tank is 37 gallons, the portable tank we were using was 28 gallons took us twice to dump black tank so I feel fairly comfortable with my estimate.

Ok, I'm convinced the tank is ok.

Why not shut the water off at nite, make sure that the turlet valve is the problem. But right,......why don't you see the water running.
In 40 yrs of RVs, I have never had a turlet valve leak water.
Bowl seal fail, yes, but never concerned me much. But they are not hard to change,
Mark_Heron
Explorer
Aug 03, 2015
Old Biscuit, yes I do have a black tank flush on front of trailer haven't had a chance to use it yet
Mark_Heron
Explorer
Aug 03, 2015
RJ's I was hooked up to city water, the campground did not have sewer hook up.My black tank is 37 gallons, the portable tank we were using was 28 gallons took us twice to dump black tank so I feel fairly comfortable with my estimate.
Old-Biscuit
Explorer III
Aug 02, 2015
Should be easy to figure out.......

Watch toilet bowl and see if water is leaking into it.

Bowl seal is not holding water so you should be able to see water build up on seal.

Toilet water valve would have to be leaking thru quite a bit for black tank to get 2/3 full over night.
A drip drip drip would not do that.....a steady stream with a bowl seal not holding would.
And if that is the case...good thing bowl seal doesn't hold water or your toilet would have overflowed and flooded trailer

Just for giggles.........do you have a black tank flush connection and is a hose connected???

Toilet/bathroom sink drain/flush connection....only way for water to black tank
RJsfishin
Explorer
Aug 02, 2015
If you're not hooked up to sewage, then I'd guess you not hooked up to water either. So then I'd guess you are using the FWT and water pump. So then I'd guess that you don't hear the water pump running abnormally, which then I would think there is no water running in the turlet.

Are you sure you are taking 30+ gallons out each time you're hauling sewage ??
What it sounds like to me is that you have been cursed w/ the "BLACK PLAGUE"!!
Somewhere in the tank there is a pile of solids that is decreasing your tank capacity by a whole bunch.
On the other note, the foot valve not sealing has nothing to do w/ your problem.
2chiefsRus
Explorer
Aug 02, 2015
rv2go wrote:
Turn on the water pump. If the toilet is leaking, you should hear the pump cycling on and off. Also, after flushing, you should pull up on the foot lever in order to help seat the seal.

x2 - if you unhook from campground water supply and use the water in your fresh water tank by turning on the water pump, you will hear the pump running if your theory is true.
Mark_Heron
Explorer
Aug 02, 2015
The grey tank as well as gallery tank seem to have the appropriate amount of discharge for our usage. This is why I have come to this conclusion, but as my wife would say I'm often wrong
darsben
Explorer II
Aug 02, 2015
Most likely it is the toilet. The only other possibility would be if they drained something else from your bathroom into the black tank. It is not common but it has been done. SO REBUILD the toilet valve and be done with the problem.
ALSO ADD a shutoff to the toilet supply line so if it happens again you have a temporary cure
Mark_Heron
Explorer
Aug 02, 2015
pulling up on lever fills my bowl and after a few minutes water has drained
HappyKayakers
Explorer III
Aug 02, 2015
Is it possible that something else (like the shower or bathroom sink) is also plumbed into the black tank? Certainly easy to check if you have a clear extension on your sewer pipe.