Black Tank Question

[Karen S]

Originally Posted by dkoldman

That sounds normal. And given that; you probably would not want the bathroom sink plumbed to gray tank.

I would do as it was suggested earlier. Get the plumbing diagram of the coach to verify how it is suppose to be. Once I know that, the next time at a dump station when both tanks are empty, pour 1 gallon down each drain one at a time just to confirm it goes to the correct tank on the drawing.

The idea of adding 19 gallons of fresh water to the black tank is a good one as it will then get you to the point where only factor remains and that would be bathroom sink usage.

Thanks. I’ll give it a try.

[Karen S]

Originally Posted by Bob Denman

Minimizing bathroom sink usage:

Do your hand-washing in the kitchen sink.

brushing teeth? This has always worked well for us at Deer Camp, and also works in the RV.

grab a small cup for some water

put some toothpaste on your brush, and step outside

dip the toothbrush in the cup to wet things down

do the whole tooth-brushing thing...

grab a swig of water from the cup, and swish it around a bit

spit that into the fire pit

dip your toothbrush in the cup to stir it around a bit

shake it out over the fire pit

empty the cup into the fire pit also



Go back inside, and grab a cup of brown ambition.

Thanks Bob.

[Janis Evangelho]

Originally Posted by Karen S

How often do you need to dump your BT?

We have the same problem with our 2017 freedom elite 29fe. The bathroom sink drains in the black water tank which in my opinion is pretty stupid. We do t worry so much when we’re camping with full hook ups but we don’t use the bathroom sink when dry camping. Wash hands and brush teeth in kitchen sink which is very annoying. We are going to see about having the bathroom sink rerouted to the gray water tank if that’s possible. We are beginning to enjoy dry camping but when your black tank is filling up so quickly it’s not as relaxing.

[Norrirn]

Originally Posted by Karen S

I just came back from a five day trip with another adult. The black tank gauge read empty on day one. By day three the gauge read full and from looking at the toilet it was full. Went and dumped the tank. Gauge read empty. On day five the gauge read full again and I had to dump it. I have a 2017 Gemini TB. The brochure says the black tank holds 19 gallons. Is it normal for the black tank to fill this quickly?

Thanks and Happy New Year.

Karen

Yes, quite normal. 19 gallons is not a lot of capacity and, as others have stated, your bathroom sink drains to your BT (for good reason) so you have to consider that. Actually, I think 5 days is pretty good for 2 people sharing a 19 Gallon container.

[Choxnpinz]

Originally Posted by EA37TS

You might want to go out to the Thor Owner's Resource site, enter your VIN, and download the plumbing diagrams for your rig. The waste diagrams will show you which fixtures are drained into the grey and black tanks. It's amazing how much one can learn from looking at the diagrams.

https://www.thormotorcoach.com/owner-resource/

Wow, how did the dealer NOT tell me about the resource site? Thanks a bunch!

[DavidH]

I’ve noticed that based on the gauge my black tank sometimes fills up or appears to very quickly. Two days is possible, but on the edge.

Sometimes I’ve noticed that after a single er sitting, the gauge has gone from empty to 3/4 or full. I attribute it to something interfering with the gauge, rather that it filling that rapidly. It may be worth noting the level more often so that you can make a judgment about whether the gauge is accurate or not. I haven’t seen that type of inaccuracy in the grey tank.

[JimDebOklahoma]

Followed link but couldn’t find a plumbing diagram.

Lots of other info there though. Thanks.

[upnyfolks]

Originally Posted by JimDebOklahoma

Followed link but couldn’t find a plumbing diagram.

Lots of other info there though. Thanks.

On the right side of the owners page for "category" choose schematics from the drop down menu, then click on the PDF link.

[LV Steve]

I have a 2019 23TB and the black tank needs to be dumped every two days.
2 adults are in the RV.

[Bob Denman]

Eat more cheese sandwiches.
They'll bind you up...

[paulwadley]

When we go out, our blk tank fills in 2-3 days and the grey tank is usually right behind it. It also depends on how many showers are taken. My wife uses the toilet a lot so I know that I will be dumping more often when she is on board. My grey and black tanks each hold 38 gallons. My fresh tank holds 36 gallons. My kitchen sink and shower go to the grey tank. My bathroom sink and toilet go to the black tank(per the diagrams).

Paul

[Jimbo56]

I’d go with the pervious suggestion of using a 5 gallon bucket to measure the accuracy of the gauge. Pour 5 gallons in, check gauge. Pour 5 more in, check gauge. Pour 5 more in, check gauge. I’d bet the gauge is not accurate. I don’t trust the gauges. I’d trust when you open the toilet valve and see Liggin at the top. So see how many 5 gallon buckets you can dump into the toilet before you see liquid when toilet valve is open.

[Karen S]

Thanks for all the input. I could be reading it wrong, but the plumbing diagram shows my bathroom sink draining into the grey tank. I did the 5 gallon bucket test and the BT gauge is reading correctly. Guess I’ll have to dump more often than I’d like or get a MH with a larger BT. 🙂

[Bob Denman]

... Midnight dumps into your neighbor's flower garden.
As long as their petunias are thriving: they won't question how it happened.

[mcr1010]

Originally Posted by Bob Denman

... Midnight dumps into your neighbor's flower garden.
As long as their petunias are thriving: they won't question how it happened.

Yeahbut, the fragrance may be a tip off.

[Travelin' Texans]

Originally Posted by Jimbo56

I’d go with the pervious suggestion of using a 5 gallon bucket to measure the accuracy of the gauge. Pour 5 gallons in, check gauge. Pour 5 more in, check gauge. Pour 5 more in, check gauge. I’d bet the gauge is not accurate. I don’t trust the gauges. I’d trust when you open the toilet valve and see Liggin at the top. So see how many 5 gallon buckets you can dump into the toilet before you see liquid when toilet valve is open.

I'll guarantee the gauges aren't/won't ever be accurate! I've had several RVs & never had one that the tanks were anywhere near accurate past the 1st tank full, especially the the black tanks, actually never payed them any mind in the last couple rvs. You can rinse, flush, add all kinds of magic potions/elixirs & waste countless bags of ice & they'll still tell you nothing useful.
With the bath draining into the black tank is actually beneficial by adding extra water to prevent poo pyramid. Unless you let the water run continuously while brushing your teeth or run excessive amounts that little amount won't affect how long to fill the black tank.
I'll also guarantee that you'll know for sure when the grey tank that the shower drains into is full because it'll back up into the shower........... about the time you're all lathered up. Same with the black tank, the toilet makes a very distinctive "burp" when flushing when it's nearing full.

[kmartin977]

Originally Posted by EA37TS

You might want to go out to the Thor Owner's Resource site, enter your VIN, and download the plumbing diagrams for your rig. The waste diagrams will show you which fixtures are drained into the grey and black tanks. It's amazing how much one can learn from looking at the diagrams.

https://www.thormotorcoach.com/owner-resource/

As per this recommendation, I now know what drains into what (bath sink drains into black tank). Thank you! I found the Schematics very useful.

Karen, At the Thor Owner's Resource site, in the list of documents, under "Category" find "Schematics" and you should find a document containing diagrams for all systems. (at least for mine it was)

[saddlesore]

Rule of thumb for RV toilets with small holding tanks......
If it is yellow....Let it mellow....If it is Brown..Flush the "accumulated" on down..
[Reduce the number of flushes,= reduced number/amount of using fresh water to refill the bowl..]

[roy stone]

The usage in the RV is not the same as a residence. You might be flushing with too much water, or flushing too much. Little pee, a drip of water, light flush. Check the instructions on the toilet.

[rudyhehn]

Are you sure it was full, or perhaps is the gauge not reading properly? The gauges get fouled with stuff all the time. When you dump the tank do you get a feeling for 20 gallons coming out? You said from looking at the toilet it was full but not sure how you could tell - I guess you can open the flap and shine a light down. We can go 5-6 days without the black tank filling, though we usually dump sooner since our gray tank fills after 4.