Forum Discussion

crasster's avatar
crasster
Explorer II
Mar 28, 2014

Pump grey tank into black tank?

I was having a cold one with a camping buddy of mine and we were talking about the fun subject of black tanks.

It got us "thinking" what if one was to place a DC pump that pumped grey water into the black tank.

The purpose of this would be to help rinse the black tank out, and to allow this process to be done while boondocking.

I know typical RV'ing dictates that grey/blackwater be dumped into specific spots, however, sometimes we go "insanely" out there....

Where a highway turns into a gravel farm road.... For miles and miles. Then turns into two tire tracks for miles and miles. Then the tire tracks vanish and there is desert and rocks (West Texas).

Out here we don't use toilet chems either (for environmental reasons). So rinsing is nice, but freshwater is lean when boondocking.

Anyway, are there any setbacks, considerations, etc., to having a pump from grey to black?

I was considering doing this on my bounder. I'll leave my class C in tact as that Toyota has shower & black tank together anyway.
  • Old-Biscuit wrote:
    I installed another dump valve on the main drain line just before the outlet.

    With it closed I can open all three waste tanks (black, grey, galley) tying them all together. Open just the grey & galley tying them together. Open black & galley tying them together. Open black & grey, tying them together.

    Lots of options with just adding one other valve. No pump, no power draw.


    This is my setup too.

    I normally just equalize the grey tanks to add space to the fullest of the two.

    I always dump black first and then let the grey backfill it. Then I dump it again and repeat until I'm happy. Seems like an easy way to clean the black without wasting more water.
  • The 'one' tank feature appealed to me when we were looking at new coaches. On our new coach, we will have one holding tank (189 gallons). The fresh water tank is also 189 gallons. This just makes total sense to me as having all the extra water go into one tank would make it easier and the black tank needs a lot of water.

    The 'holding tank' also has a sprayer system to clean the tank like we have now on the Dynasty.

    The new coach also has a grey water bypass valve so if it is allowed, we could release grey water on the grass and it not go into the holding tank (I don't think I would ever use that feature).

    MM.