Waste tank usage
 

In my old Monaco, it was easy... toilet goes to the black tank, everything else to the grey tank. But noticed that in my 2015 Aspire the kitchen sink and front toilet drain into the black tank, have not been able the determine yet where the rear toilet, shower and bathroom sinks go.

Anyone know how the tanks are being used. Thanks!

Could you open a valve at a time and then run the plumbing in question?

You sure about that? On my coach the toilets and mid bath sink drain to the black, all else to gray.

Kitchen sink should be draining to grey, bathroom sinks to black. While hooked to sewer, just open the grey tank valve and run each sink one at a time and you can tell if they are draining to the grey tank or not.

Entegra drained the bath sinks to the black tank on purpose to increase water volume in that tank to prevent the famous pyramid of poo that has been written about everywhere on the forum. Most people don’t add enough water to the black tank when flushing solids and paper. It does of course fill the tank up faster. If you treat the black tank like a septic tank and wait until it is 70-80% full before pulling the handle the woosh affect draining the tank, followed by sign the tank flusher will keep the black tank free of poo pyramids.

The solution to the “pyramids” is definitely more water, however, should you get into that dilemma, simply put a few good skirts of dawn dish soap down the toilet and go for a bumpy ride. Cleans the black water tank like new. Also, I always wait until I have accumulated at least a quarter tank before I dump the black water to aid in the “flow”.

That is how I tested my system on our 2016 Aspire 42RBQ. Completely drained gray tank and left valve open then ran water in each sink. All sinks caused water to drain out of the gray tank. From that I concluded all my sinks drain into the gray tank. This is obviously not the case on all EC models.

I think 2016 is the changing point, before at least one sink to Black tank, 2016 and later all sinks to grey and only toilets to black. So yes, it is important to use plenty of water in toilets AND I always start it with a couple of gallons of fresh water in the bottom after draining. JMHO

We've always understood the reason for draining all but the toilet into black but we also learned a long time ago that it was never nearly as full as the grey became, and we boondock a lot.

One tip we learned early on was to use a dish pan in the kitchen sink and dump the grey water into the toilet to save space.

According to CS some 16s ( mine for one ) were still plumbed with the bathroom sinks emptying into the black tank. I think the electric flush toilet supplies plenty of water for the black tank so mine will be switched over to the gray tank at our AIR.

Unfortunately, our 2017 Entegra has 2 Macerator toilets. These types of toilets use a lot of water, compared to the older foot pedal ball valve style in our last coach.

As a result, our black tank fills about twice as fast as our gray tank.

Boondocking in our coach requires being mindful of toilet usage. We always max out black before we have any issues with gray, or fresh.

Our Phaeton was good for about 5-6 days before the gray would fill.

Our Aspire is good for 2-3 days at the most before the Black is full.

One issue is the black tank in the Aspire is fairly small. I seem to recall it’s around 41 Gal. By comparison, the gray tank is 62 Gal. and fresh is 100 Gal.

By volume, the black is clearly the smallest. The main issue is that for every toilet flush, there is a substantial amount of water in addition to waste going into the black.

This is such an issue in our coach, I’ve periodically contemplated simply combining both tanks to gain a day or two. I haven’t yet done this, and really don’t want to.

Frankly, one of two things would improve the situation. Either install a bigger black tank, or provide a toilet that uses less water per flush. I believe some coaches do have a gravity toilet in the mid bath. That is a good solution.

-Matt

Combine them!

Waste water is waste water.....grey or black
Grey can be NASTIER then black due to grease/oils, food matter, body oils/sloughed skin etc.

I installed a 'extra' valve on the common dump header----easy to do on my 5th wheel.
With it closed I can open both grey/galley dump valves combining them OR open grey/galley & Black dump valves for 128 gallon capacity of 'waste'
OR
Dump black tank...close 'extra' valve ---open grey and back flush grey into black for added rinse

Mine is permanent....a twist on model is available .Goes on end of dump header then sewer hose.
Gives one OPTIONS


It wasn't all that long ago RVs only had ONE waste tank.

OP....
Has 80 gallon fresh water
50 gallon black and 50 gallon grey
Bathroom sinks draining into black means better conservation of bathroom sink usage needed.....do NOT leave water running while washing hands/face, brushing teeth etc

If you combine, you have no Sani-Con on the gray tank, and if you let them all mix together, you are going to get toilet paper and other solids in the gray tank and you have no means to effectively get the gray tank cleaned other than the old "pour in some Pine Sol and Dawn and let the road bumps clean the tank" process which I don't think is a very good strategy. Keep your gray and black tanks separate. JMHO

Gary

Gary, that is a very good point, thanks for bringing that up.

-Matt