Why do RVs need separate grey and black water tanks ? Does your coach ?

[richard5933]

I'd agree that a macerator toilet can add needless complications. But, having a combined gray/black tank does not require a macerator.

[Lin]

I have had both setups.  My current bus has one tank but does have a bypass for the gray water.  I have used it lots of times that way.  I run a hose from the discharge to a nearby bush, which usually appreciated it (I think).  Now if you were to let the water just pour onto the ground and puddle, it would be a different story.

Also, when we do it the water is going right from the faucet to the bush.  If it were sitting in a tank and putrefying, that would not be pleasant.

[pabusnut]

I built my setup with a 100 gal graywater and 50 gal blackwater.  I have a 100 gal freshwater tank also.

When I started the conversion I had 4 kids at home(3 girls).  I know have one, because I am a slooooooowwww bus converter.

My intention was to  be able to dry camp for a week or so.  I now know that with 3 girls that would be near impossible.

I also designed an overflow from the gray water to the black water tank, fitted with a one way valve, in case the gray water fills before I can dump.  I think it would take more than a week to fill the black water.
At least it gives me options if I can't dump the gray on the gound, and more time to get to a dump station, or fill a portable disposal tank.

Steve Toomey

[Gary Hatt - Publisher BCM]

I have had both setups.  My current bus has one tank but does have a bypass for the gray water.  I have used it lots of times that way.  I run a hose from the discharge to a nearby bush, which usually appreciated it (I think).  Now if you were to let the water just pour onto the ground and puddle, it would be a different story.

Also, when we do it the water is going right from the faucet to the bush.  If it were sitting in a tank and putrefying, that would not be pleasant.

I like this idea. It has the advantage of using one tank for both grey/black so it will mix up and flush better so there is less chance of solids building up in the bottom of the tank which is a problem for some people.  I had one each 250 gallon fresh water and one 250 gallon grey/black water tank in my MC-7.  I could go a month without filling/dumping with this setup and I hate having to dump so this worked well with me.  The only problem was that it took a while to fill the tank and you can hold up the line in a dump station, so frequently I could not fill it all the way.  I did not have a grey water diverter for when boondocking, but I would have that on my next bus if/when I build my next bus.

[silversport]

I will stick to the two tank system. The way I set it up two 90 gal tanks offset, 4 in dump off black tank, gray tank dumps into the back side of black tank (electric valves). Dump black first then rinse with gray. The tanks are tied together at top for over flow, no one way valve, in ten years never came close to fill black tank, twice over filled gray. With our system we gone three weeks.

[Jim Blackwood]

The gray water tank will always get full first. No real way around that except to drain it to the ground. By far the largest contaminants of gray water are phosphates. Soaps and detergents in other words. What little dirt and such is included is far in the minority. But, so is the soap in proportion to the water which is why the environmental impact is usually minimal. Far less of an influence in the rainy east than it would be in the desert for instance because the normal rainfall will dilute it even further and existing organisms will happily and quickly break down anything in the water. It's not even remotely close to the contamination level from a black water spill, and even that will be quickly neutralized if it is not chronic. Plus, the gray water quickly goes away. It is possible of course to make a nuisance of yourself, and if you do that you have nobody to blame if an authority figure shows up with his ticket book. But it's just as easy to avoid being a nuisance and have that same authority figure give you a pass. Your level of effort should be commensurate with your perceived threat level. If NOBODY in the area EVER dumps gray water maybe you shouldn't either. And I've heard that in some parks out west that is the condition. But I've never heard of that around here.

I like both G and B tanks for the flexibility. If the G water can be dumped it means the fresh tank can greatly exceed both the waste tanks for extended boondocking and the B tank becomes the limitation if there is enough fresh water. But I plan to run the bathroom sink into the B tank as it is on the same side of the bus. It's possible I may consider running a washing machine discharge there as well. But the shower and kitchen will go to the G tank, which discharges through the B tank when dumping. I hadn't considered overflowing the G tank into the B but that is worth thinking about.

One thing I would certainly not like would be the possibility of overflowing a combined tank into the shower. That's just too nasty to even consider.

Jim

[TomC]

I have a 130gal fresh, 85gal gray, 45gal black. The gray always gets filled first. I have a street dump on the passenger side. just pull up to a street drain and dump it-or like others said in the desert. My truck has 200gal fresh, 115gal gray, 69gal black. I can dump my gray through the black to rinse. I'll always have separate. Good Luck, TomC

[someguy]

I have a 130gal fresh, 85gal gray, 45gal black. The gray always gets filled first. I have a street dump on the passenger side. just pull up to a street drain and dump it

Is it legal to dump grey water down down a street drain ?   Don't street drains carry rainwater and runoff, which is supposed to be clean ?

[dtcerrato]

I guess it matters what it says on the drain cover! The word sewer rings a bell!

[richard5933]

Is it legal to dump grey water down down a street drain ?   Don't street drains carry rainwater and runoff, which is supposed to be clean ?

Generally speaking, in most parts of the country NO.

What people are discussing dumping here (gray water) is NOT clean. If it is, then just pump it back into your freshwater tank and use it again. It's contaminated - not to the extent of black water for sure, but it's contaminated with all sorts of things.

Storm sewers and street drains usually drain into a body of surface water, like nearby streams and creeks. Dumping anything into them is usually illegal. Even were we are camping right now in the northern part of Wisconsin I noticed that it's molded right into the street drain covers "no dumping".

Many (most?) states have regulations on dumping things like phosphates, cleaning solutions, etc. into the surface water system.

What's being discussed used to be common. Our bus was built with a pneumatic dump valve that exits about a foot in from the curb side of the bus. I'm told that the original owner had a floor drain he dumped into at his shop. My suspicion is that he had many more of them along the route he used covertly.

It's amazing to me that we, the generation that watched rivers catch fire not too many years ago, is having this conversation. Don't flame me - I know that there is a difference between dumping industrial waste and shower water. But, this whole thing is about being responsible and stepping up to handle our own mess without creating a burden for others.

[luvrbus]

Storm sewers do carry off some nasty stuff after a rain and all ends in the ocean sooner or later ,I really don't know of anyplace it would be legally allowed,the EPA controls storm sewers.if you think about the crap that washes from your lawn and drive ways it's probably worse than gray water though plus the dead animals,oil bleeding from asphalt and other things.Storm sewers are nasty.I spent big bucks protecting storm sewers from run off at Walmart sites under construction and after a rain fill out a report and send it to the EPA.Gray water can you see in your mind the crap in W/M and shopping centers parking lots that drain into storm sewers it's not pretty   

[DoubleEagle]

My first Eagle Coach was set up very similar to Richard's after I had toured Custom Coach in Columbus and saw how they did things (two 100 hundred gallon tanks), and has worked just fine. Back in the dark days of owning a RV, one of the last ones I had was previously owned by the owner  of an auto parts company that toured every state and Mexico & Canada demonstrating his products. It had modest sized tanks, but it also had a custom crafted wire and pulley system that was operated from the drivers seat that allowed the sewer tank to be cracked open while going down the road. When it was convenient, like during a rainstorm, he would dump away. It's not quite as bad as that driver of the Entertainer bus that opened up the valve while going over a bridge in Chicago and dumping on a sightseeing boat down below, but it still stinks. 

[luvrbus]

You need to read the regulations on what ships and boats can dump in the ocean,lakes and water ways

[richard5933]

Storm sewers do carry off some nasty stuff after a rain and all ends in the ocean sooner or later ...

But Ma, all the other kids were doing it...

No doubt what you're saying is true. But, I didn't think the question is "Do others do it?", or "Are there are worse things going into the surface water?" I thought the question is "Should we be doing it?"

Milwaukee has an older storm sewer system which is a total mess - all the street sewers go through the sewage treatment plant. Many older homes in Milwaukee also have their downspouts connected to the sewer system. The original purpose was to prevent things like you describe, like street runoff and parking lot debris, from entering Lake Michigan. Since we get our drinking water from Lake Michigan, it seemed like a good idea.

Eventually the system got overwhelmed and they started to have to have bypass times during heavy storms. Now they've started the process of disconnecting downspouts from the sewer system.

For an intelligent species, it strikes me as odd that we so freely piss and crap almost directly into our drinking water supply, and then sit back and wonder why people get sick.

You need to read the regulations on what ships and boats can dump in the ocean,lakes and water ways

And how far out do they need to be from shore to do that?

[dtcerrato]

There is a stark difference between a storm sewer & a sanitary sewer and are usually plainly marked even sometimes with international symbols (ie: a "fish" pictured on the cover plate means it ends up straight into the local water source).
It is perfectly legal (most of the time but contingent on local ordinances) to dump sewage into a sanitary sewer drain.
It's no different than hooking a macerator pump up to our black tank slide valve & pumping into a toilet.
Art Carney was my favorite & to add to that Dad was superintendent to municipal water & sewer departments in South Florida after retiring from the northeast refinery - ESSO. 
We're confident through Richard's dialog that he is (as hopefully most of us)
responsible for doing the "right" thing - Especially after picturing an auto - dump valve in his Country Coach plumbing!

https://bfplumbingbayarea.com/blog/storm-drain-vs-sewer-system/

Remember the exhaust system ejection system?

https://www.irv2.com/forums/f59/never-need-to-dump-again-128137.html