Been parked for 9 days at a CG with no sewer on site. We've been careful to go to the toilets on the CG most if the times except nights and early morning. Of course, the sensor showed 3/4 full after two days so we knew not to trust it too much from there but I think the waste have caught up to the sensor by now. Question is: once the sensor shows full, how much room is there still? ( kinda like how far can we drive on Empty).We still have 5 days before going home and would rather not have to go dump until ready to go.Also, what happens if we keep using when the sensors mark full if we can't see anything in the tank through the toilet hole?I should add that the black tank is 37 gallons and there are two of us in the trailer.

You will know when it is full! It may burp some air when flushing. Or, you will see the...ummm...stuff through the black hole. Forget about the sensors.

you can open the lid on the john and using a flashlight see where the level is. if you can see water then it's time to dump. but we've taken all of the stress out of this. experience has taught us that we (there's just two of us) can use the facilities in the MH for a week without *having* to dump. so I just dump the tank once a week or when we leave the park/CG, whichever comes first.

Sound is a good way for me to tell. It sounds different when you flush and it is near full

You should start seeing "stuff" through the hole in the toilet when the tank is full.One thing I was told when going through my initial inspection was to avoid using too LITTLE water when flushing. You don't want the black tank packed tight with solid material but rather more liquid then solid. A higher concentratiion of liquid versus solid will help move the solid stuff out of the tank when dumping. This is probably more important if you don't have a black tank spray installed to rinse the tank after dumping.I was also advised that after dumping to put a couple of gallons of water into the tank with a packet of black tank treatment to prevent any remaining stuff from solidifying.

We've used it mostly for urine and threw toilet paper in trash to save space. We do have a black flush and will use it.I guess my concern was for spillage on our way to the dump site if too full.

How full is full? (Black tank) | Good Sam Community

27 Replies

boubou64
Explorer
Sep 09, 2013
On the road again...
We made it a full 14 nights on
37 gallons black tank. The sensors still showed 3/4 full and looking in with a flashlight, I could see there was still about 2 inches to the top of the tank. We used the parks toilets during the day but morning/ evenings and nights we used ours. Our trick which is a little gross (but we didn't want to hook up a d dump) was to throw the toilet paper into the trash and only flush when toilet was full and allow only a little fresh water back into the bowl for the seal. (Flush each time for the brown stuff of course).
Dumping this morning was all concentrate!!!
wa8yxm
Explorer III
Sep 05, 2013
I can not tell you how full full is.. But I can tell you how full too full is.

MAJOR STINKY MESS

So when you THINK it is full..... that is a good time to make it EMPTY.
boubou64
Explorer
Sep 05, 2013
Day 11 and still showing 3/4 .... The light flickers at full fir a second but goes back to 3/4
Away for today so not going to use it until tonight. That leaves 3 days to go before we dump. Feels like an accomplishent to make 37 gallons black tank last 14 days!
Norskeman
Explorer
Sep 05, 2013
Sensors are not accurate after using the tank for awhile. Gray and Black. When it burps it is full.

I take one of these along,Thetford SmartTote LX Portable Waste Tank - 18 Gallon, for gray and black water (mostly gray) when we camp where there is no full hook up and we will be there for more than 3 days. Easy to pull behind the truck when dumping is needed and easy to rinse out.

http://www.campingworld.com/shopping/item/thetford-smarttote-lx-portable-waste-tank-18-gallon/37870

Good price and free shipping now. I purchased ours at the local Camping World.
RJsfishin
Explorer
Sep 05, 2013
Each RV is different, but the flashlite works on all of them.
If the head is mounted directly above the tank, there is a short pc of 3 inch pipe that extends from the floor flange into the tank about 3 inches. When the level hits the end of that tube, I know I have about 3 days left.
John___Angela
Explorer
Sep 05, 2013
We have gone 14 days on a 40 gallon tank. She was full. ??
64thunderbolt
Explorer II
Sep 05, 2013
rk911 wrote:
you can open the lid on the john and using a flashlight see where the level is. if you can see water then it's time to dump. but we've taken all of the stress out of this. experience has taught us that we (there's just two of us) can use the facilities in the MH for a week without *having* to dump. so I just dump the tank once a week or when we leave the park/CG, whichever comes first.

with the plumbing on mine if you see it it's FULL. there's an elbow just below the toilet. Most 5ers are like that because of the basement storage.
BFL13
Explorer II
Sep 05, 2013
Not experienced a "burp" AFAIK, but ours is full up when you get a "splash back" when you flush the toilet. At that point it still flushes down, but you are pushing your luck.

Related note, we have a grey tank just for the tub and bathroom sink. When water backs up into the tub and will not drain, that grey tank is full! (We have a separate galley tank for the kitchen sink)
Moderator
Moderator
Sep 04, 2013
Moved from Lifestyle
doxiemom11
Explorer II
Sep 04, 2013
DH and I have gone as long as 14 days with occasional use of another bathroom. We cut back on the amount of water we used to flush as we were being very generous with that when we have FHU. It was full right up to the blade that opens. Definitely time to dump.

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How full is full? (Black tank)

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