extending grey tank capacity

Tundra57

I was boondocking and filled my grey tank. The black was empty maybe a gallon.

If i left the cap on the waste water dump outlet and pulled both dump valves, could i back fill the black tank from the grey tank a little ?

Sharon_is_SAM

It may be better to not risk contamination of your gray tank and just drain off a bucket from the gray and pour it down the toilet.

JEB

Sharon_is_SAM said:

It may be better to not risk contamination of your gray tank and just drain off a bucket from the gray and pour it down the toilet.

Yes. This works very well.  To facilitate a controlled gray water drain, get a sewer cap that has a threaded outlet that fits a garden hose.  Another method is to prevent gray water from getting in the gray tank to begin with.  Get a small collapsible sink used for camping and put that in the galley sink.  Do your dishes in that sink and then dump the dishwater down the toilet.

Cbusguy

Guess I don't understand what the big deal is about a bit of exchange between the black and gray tank.

The only thing I can imagine would be that the grey isn't vented and you would get the smell in the camper.

Why else?

ScottG

Even if this did work (which theoretically it would) your capacity would probably be pretty limited. Much of the black tank sits above the level of the shower floor--once both tanks are filled to that level, you will still get backing up through the shower drain. And, when that happens, you will now have black water in the mix...

They grey tank is vented. If it weren't, your traps would not function properly.

Sharon_is_SAM

Yeah, the gray and black tank share a vent.

klenger

I've dumped the gray tank into a bucket (several trips) and dumped that into a nearby toilet.  It took about 4 or 5 trips but much easier than packing up and going to a dump site.

Verna

I use a 5 gallon “former” water jug to drain off 5 gallons at a time of gray water and dispose of it at the RV dump. It takes up less room than the 25 gallon portable “Blue Boy” that I keep in Arizona. I wrote GRAY on all 4 sides, the bottom and the top so no one gets confused as to what it’s purpose is. 

TNOutback

A cap on the waste pipe that has a garden hose outlet on it.  A short section of garden hose with a sprayer on the end.  Then into a bucket or a small gray tank.  the hose end sprayer lets you meter out the gray water without overflowing your container. Close the gate valve when your container is about full, then empty the hose.  Obviously this is a solution for letting out gray water only.

BirdieJane

So your question included “black was empty maybe a gallon.” So your grey water is now black water. When you remove the cap you will have sewage not just grey water. Could be even more difficult draining through the garden hose connection depending on what was in your blackwater tank. I think it wiser to catch grey water, or drain into a bucket and dump it else where. Some areas you can dump grey water, but once it has any black water mix with it, all of it is considered black water. 

jkjenn

I have a couple of Barker 5 Gallon portable waste tanks for long-term boondocking, when there is no other option. I could then store the waste until I went to a dump station. This helped me stay parked in the same spot for 2 weeks at a time, even with an 11 gallon grey tank.

I know some of you are thinking why not just dump on the ground, but you really dont want to do that if camping near water. 

Dalehelman

Question what do you do with gray water from your outdoor shower?  What do you do with water when you are finished doing your dishes outside when camping? 

jkjenn

Dalehelman said:

Question what do you do with gray water from your outdoor shower?  What do you do with water when you are finished doing your dishes outside when camping? 

Bought the T@b so I would have to deal with neither of these!

SweetlyHome

We camped for years in tents, a traditional teardrop trailer, and primitive pop trailer all with no plumbing.  There were so many cramped public and private campgrounds without a provision for doing dishes or proper of dumping grey water, it was unreal.  Often there were signs do not dump grey water, do not wash dishes in bathroom sink.

We wrote so many negative comments in surveys on this issue.  Still do if we note the condition.  

What were we supposed to do??

Marceline

Dalehelman said:

Question what do you do with gray water from your outdoor shower?  What do you do with water when you are finished doing your dishes outside when camping? 

I backpacked/tent camped for most of my life and depending on the campground I still wash dishes the same way that I always have. I have a tub that fits in the sink of my clamshell kitchen and I use biodegrable soap. 

Dalehelman

@Marceline
The question was what did you do with the gray water?

JEB

Dalehelman said:

@Marceline
The question was what did you do with the gray water?

I looked for someone who was dumping gray water in their site and dumped mine in their site as well.  

In all seriousness, this is a silly false equivalent. There is a big difference between dumping out a small camp sink and popping the knife valve on a 18+ gallon gray tank.

Vikings

Dale, you are presuming an outside shower results in gray water...some would object to that characterization...tsk tsk!
Now dishwashing water...which is gray, sometimes waters a variety of plant life.
;-)    

Bayliss

We wash everything outside (and dump the wash tub water in the dirt, plants, or whatever is present at our campsite) if at all possible, and we use biodegradable soap (e.g., Dawn liquid detergent), or biodegradable soap/shampoo when showering, whether inside the camper or outside.  Regardless, whether using the camper sink (and gray water holding tank) or washing things outside, BEFORE washing any dishes, utensils, pots, or pans, we always wipe them as clean as possible with paper towels or napkins and toss those in the trash.  HOWEVER, we have never just dumped gray water from a holding tank into the camping area, because it will smell (enough other campers near us have done it, so I know.)  Besides, in general, dumping gray holding tank water in an unauthorized location (e.g., a campsite or the side of the road) is not good for the environment or nearby waterways, even if we have done our best to pretty much only allow slightly dirty soapy water down the drain.  We just have to be judicious in how much water we send to the holding tank so we can avoid having to hitch up to go and dump.  Although we haven't had an issue yet, it definitely is a challenge with the small holding tanks on a T@B 320S.  We used to last two weeks dry camping in our 5th wheel without any problem.

Marceline

Dalehelman said:

@Marceline
The question was what did you do with the gray water?

I handle it just like I did when backpacking/tent camping - ie. fling it across vegetation well away from any stream or creek. 

Marceline

JEB said:

In all seriousness, this is a silly false equivalent. There is a big difference between dumping out a small camp sink and popping the knife valve on a 18+ gallon gray tank.

I think that the point is that you can minimize the need to dump your gray tank if you're more careful about what you're putting into it in the first place. I would never suggest dumping an entire gray tank on the forest floor. But I can't see any reason that you can't handle gray water the same way that someone tent camping in the same campground is handling gray water.

GatorEgg

This thread has morphed into the discussion I frequently  have with my sailing students.  Why is it illegal to dump my boat tank in inland waters but not for my whole crew to hang their rears over the side of the boat and dump whatever comes out of them over like all the animals do?

JEB

GatorEgg said:

This thread has morphed into the discussion I frequently  have with sailing students.  Why is it illegal to dump my boat tank in inland waters but not for my whole crew to hang their rears over the side of the boat and dump whatever comes out of them over like all the animals do?

As in all things, it is a question of degree. Do you use gloves at the dump station?  Why?  Do you use gloves when you wipe your butt at home?  Something in small innocuous quantities can become a problem in larger ones. 

BrianZ

The original question was interesting & showed some creative "out of the box" thinking; however, knowing that the black tank is the only one located above the floor (you're sitting on it when sitting on the toilet) pretty much answers "no" to the main question.  Still, it would be an interesting test, so if anyone tries it (like with plain water on a new unused T@B), please let us know if you do, in fact, get gray water (or black & gray) rising up from your shower drain. 🤪

BrianZ

@JEB, generally, no gloves; however, it's usually easy enough to stop at a campground toilet on the way out & wash hands with soap after rinsing with a hose.

klenger

Back to the original question, "No" I would not, but you could safely dump gray water into a bucket and then dump it into the toilet with the same but more sanitary end result.