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Grey Tank Drainage

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Can the sewer drain be deployed for the length of  a stay at a full hookup site?


As a neophyte, it seems to me that the front of the trailer (at the ball) has to be elevated to about 30" to achieve continuous draining of the grey tank -- this makes the trailer slope uncomfortably. I thought that, at a certain level of capacity, it would start draining and effectively stay at that  level without needing any front elevation. Not so, in my case. I filled the grey tank by opening the kitchen faucet and letting it drain. Without elevating the tongue, it still just trickles out weakly. But by  then elevating the tongue, it just whooshes out.


Count me as thoroughly confused. But then again, at 75 years old, confusion is perhaps my new permanent state.

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When we’re with FHU we let the gray tank fill before draining. It’s usually also when we dump the black. The gray provides a rinse. I wouldn’t want the gray to be continuously open because I don’t want my basement open all the time. We have dumped the gray independent of the black if we’re showering a lot. I usually raise the front of the trailer a bit when draining the tanks, especially when we’re leaving the campground. Mike

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Texas Hill Country | 2016 Elite II #135 | 2020 Ram 2500 6.7L


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We will occasionally let the grey water drain if we’re in an area that allows that. We hook a long garden hose to an adapter on the drain to get the water away from the campsite. It doesn’t flow quickly, but it’s enough to keep up. We keep the trailer level and I open the valve just enough that I can close the basement door.


I just bought an adapter that will allow us to connect our grey water hose to a sewer connection so that we can do the same at campsites.


I believe that both the fresh and grey tanks are set on wedges that should allow the tanks to drain with the trailer level.

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I would add to what Mike stated just so it's very clear: you also never want to leave your black tank valve open when you are at a site with full hook-ups.


Let your black tank fill to 80% or more and then dump it all at once. Then, drain your gray tank. The GT is notoriously slow to get the last bit out. You don't need to raise the front to extreme heights however. Just raise it a bit and then wait if you have time. If you leave your BT valve open full time while camping, the liquid components of the tank will outrun, and separate from the solids. The solids then collect in the tank and will turn into a hard mass, often called the "brown pyramid". You don't want to go there! Waste tank management seems ominous at first, but you learn fast and it's very easy to balance the two come dump time.






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2015 Oliver Elite, Hull 107

1998 Ford E-250, 5.4 liter

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We have the composting toilet and use the same method as Overland and the same adapters--garden hose, etc. We also discovered that we can open the gray-water valve just enough that we can close the basement door when hooked up to a sewer drain. (I understand the need to flush last with gray water if one does not have the composting toilet.)

Onward through the Fog!

EarthPicks of Cochise County


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I have found that completely draining the grey tank requires a decent front to rear elevation drop. Most of the time this requires extra effort due to the rear location of the drain, and the low placement of the tank/trailer  (and the dump station set-ups) . I let the tank fill, and drain once upon leaving.  We do not use the black water system, as we use the compost system. After the last 40 days of continuous use, I have little to complain about with my Ollie, dumping the grey water is a minor concern, once you develop your system. By the way, the grey water doesn't always need to go in to a "dump station".

Cindy,  Russell and  "Harley dog" . Home is our little farm near Winchester TN

2018 Oliver Legacy Elite II - 2018 GMC 2500 Duramax 

"Die young - As late as possible"





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