Greywater overflow to blackwater?

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edubb

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North Georgia
Hello,
I just purchased my first ever RV, a travel trailer, so let me show my ignorance by asking:  Does the greywater tank overflow to the blackwater tank, with a flapper valve to prevent the reverse?

-Eric
2005 Surveyor 260
(but not in the driveway yet!)
 

Tom

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Hi Eric. The simple answer is no, although there are always folks coming up with creative alternatives/solutions.
 

John From Detroit

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Davison Michigan
I'll second Tom's by saying "Not that I have ever seen" in fact I'm not sure it would be legal

(Note: Not sure means just that, I seriously do not know, and would need to check it out)

Well... That said, My rig has 2 Gray tanks and one black
 

Carl L

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west Los Angeles
edubb said:
Hello,
I just purchased my first ever RV, a travel trailer, so let me show my ignorance by asking:? Does the greywater tank overflow to the blackwater tank, with a flapper valve to prevent the reverse?

Like the others have said, no.  However, unless you are boondocking, not to worry.  Unlike the black tank, the grey tank is left open to the sewer when hooked up in a CG, so most of its capacity is used for on the road use and the occasional boondock.
 

edubb

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42
Location
North Georgia
Have to say that this forum is excellent for newbies....and I suppose even for veterans to share information.  Anyway, thanks very much for all the tips you've given me.

I was thinking that some (a lot?) state parks have water/electric at the campsites, but a dump station for when you leave.  If you stay 2 or 3 nights, it might be nice to have more grey storage than black.  But I see where there might be technical issues with this idea...

-Eric
 

Wendy

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Colorado
Our bathroom sink drains into the black tank. And we actually fill up the black before the grey. No cracks but that must mean we're full of something......
 

Karl

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Elkhart Lake, WI for the summer. Work at Road Amer
Eric,
It all goes back to how conservative or lavish you are with your water use. If you/spouse/kids take 20 minute showers, you can expect to fill up your gray water tanks quickly. Most of us have learned that rv life is not like life in a stick house. You make adjustments. That said, if you are only talking about a 2-3 day trip, you should have no problem with either the black or gray tank capacity, UNLESS you have a travel trailer with nothing more than a Porta-Potty - totally different story.
 

Gnuman

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wendycoke said:
Our bathroom sink drains into the black tank. And we actually fill up the black before the grey. No cracks but that must mean we're full of something......

Not anymore  ;D
 

Carl L

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edubb said:
Have to say that this forum is excellent for newbies....and I suppose even for veterans to share information.? Anyway, thanks very much for all the tips you've given me.

I was thinking that some (a lot?) state parks have water/electric at the campsites, but a dump station for when you leave.? If you stay 2 or 3 nights, it might be nice to have more grey storage than black.? But I see where there might be technical issues with this idea...

Well, us old trailer trash types figger to use paper plates, plastic forks, Handi Wipes for hand washing, and campground showers for baths.  That may be why no one camps near us, but there you are.  ;D
 

edubb

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42
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North Georgia
wendycoke said:
Our bathroom sink drains into the black tank. And we actually fill up the black before the grey. No cracks but that must mean we're full of something......

Carl Lundquist said:
Well, us old trailer trash types figger to use paper plates, plastic forks, Handi Wipes for hand washing, and campground showers for baths.  That may be why no one camps near us, but there you are.  ;D

Hah! :D :D
That's interesting about the bathroom sink, I'll have to look at ours when we pick it up.  That would help balance things a bit.  Our trailer only has 30 gallons of grey storage, not that I'm complaining, I used to backpack for 8 days at a time, used 3 gallons a week!
 

Carl L

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edubb said:
Hah! :D :D
That's interesting about the bathroom sink, I'll have to look at ours when we pick it up.? That would help balance things a bit.? Our trailer only has 30 gallons of grey storage, not that I'm complaining, I used to backpack for 8 days at a time, used 3 gallons a week!

Well I backpacked likewise.  However, let me tell you right now, most RV parks get rather up tight about folks digging cat holes in back of bushes or rocks. 
 

Jim Godward

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Hillsboro, Oregon
There are several schemes to move grey to black tanks.  One of the best for control, in my opinion, is to use a pump from the grey to the black with the inlet to the black above the tank in a vent pipe.  Have the switch controlling the pump where you can VISIBLY see the level in both tanks or where you have a good monitor to assure you do not overfill the black.  That is obviously quite bad!!
 

edubb

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Nov 17, 2006
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42
Location
North Georgia
James Godward said:
There are several schemes to move grey to black tanks.  One of the best for control, in my opinion, is to use a pump from the grey to the black with the inlet to the black above the tank in a vent pipe.  Have the switch controlling the pump where you can VISIBLY see the level in both tanks or where you have a good monitor to assure you do not overfill the black.  That is obviously quite bad!!

Interesting idea. 
Are grey tanks vented to atmosphere, so if the tanks interchanged gases it wouldn't be a problem?

Has anyone tried a PVC interconnect at the top of the tanks (flapper valve to prevent black-->grey)...or maybe in the plumbing just above the tanks. I guess you'd want a turn-down ell inside the grey tank so that you don't skim any floating food waste off the grey tank, which might mess up the flapper valve....this sounds complicated, nevermind  :)
 
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