# Grey Water Tank Cross Over



## dalor (May 27, 2012)

I have been using my trailer for the summer and have in all cases filled the grey water tank connected to the kitchen sink before the bathroom grey or the black tanks. Has anyone ever considered putting a crossover drain between the 2 grey water tanks to increase the usable life of the small tank before manditory drainage. Opinions welcome!


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## Oregon_Camper (Sep 13, 2004)

Small Tank?

I think both of the grey tanks are 30 gallons each. I have considered doing what you are talking about, but in reverse order....dump the shower grey tank into the kitchen grey tank.

I can normally go all summer and perhaps empty the front tank (kitchen sink) 1 time...maybe 2 times. 
You and your family must wash a LOT of dishes.


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## KTMRacer (Jun 28, 2010)

I did and it is very easy to do IF you have a single 3" sewer drain hookup. Here is the trick

1) buy a 3" twist on gate valve. They are sold to for a replacement for a leaking glue on gate valve
2) when you want to crossover, install the 3" gate valve on the main drain exit close it off, open the two grey tank valves and once equalized, close them again. Then, if needed open the twist on valve and you will get a few cups of grey water to drain out. We do this quite often since our bath grey tank usually fills before the kitchen. Or, you can do this hookup and just leave both grey valves open all the time.

AND here are a few more tricks you can do with this setup.

If your black tank is not full and grey is full, Install the twist on valve and again with it closed, open the full grey tank valve and then the black tank valve. Grey will backflush into the black and equalize and you'll gain grey tank room

When you go to dump, again install the twist on valve. Open it and then open and drain the black tank and leave the black valve open. Then close the twist on valve, open a grey tank valve and let it backflush into the empty black tank. Then close the grey valve and open the twist on valve. Cleans out the black tank. Repeat as needed. When done flushing the black tank, close it and then finish draining the grey tank.

I remove the twist on valve when traveling since it sticks down another 6" or so and don't want it to snag on something.


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## Oregon_Camper (Sep 13, 2004)

I just dump grey water in campground if needed. I know some will disagree, but we camp in VERY remote locations...and I don't do it where it could enter a lake/stream.

I see all sorts of pop-up tents that people stand in to take a shower....so I see no difference in dumping my grey water when needed.


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## MT MIke (Aug 13, 2011)

I'm with Oregoncamper. I boondock 99% of the time, and have twice needed to drop a little gray water to complete the stay. There is a thread about fresh water in the forums also. I always have a full fresh tank, as we rarely camp with hookups. NFS water from a pump tends to have a bit of sediment in it, so I'd rather not send that through my camper's plumbing.

Mike


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## dalor (May 27, 2012)

thanks for the ideas on equalizing the grey tanks. Sorry for my long absence from the community.


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## deepvee16 (Jan 27, 2014)

Like Oregon Camper, we get very little in the galley tank since we do our dishes outside. And, I don't like having food stuff in the tank. I agree about leaving grey water on the ground. It is no different than tent camping and doing dishes and showering outside. Unfortunately that's not always convenient at certain "close quarters" campsites. When doing so, I attach a small discrete 3/8" tube to the outlet cap that has the garden hose fitting on it. Then discretely move the tube to a nearby tree or gravel area and it slowly drain.

The removable gate valve is ideal for those times when we can't drain. Double your fun! Although not all trailers tanks share the same outlet.


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