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dwurnitsch's avatar
dwurnitsch
Explorer
Jul 12, 2015

Black Tank Fillin to Fast

Motorhome - 2000 Safari Serengeti

The black tank in our MH on our last couple of trip has overfilled twice only 2 days into our trip. After the second time we could hear water going into the black tank while using the sink in the bathroom. I know, impossible.


We completely drained and washed out the black tank to do some of our own troubleshooting. Gray tank registered at 60% which is usually pretty close to actual. We turned off all the water to our MH and used a garden hose and placed water into the bathroom sink and could hear water enter the black tank and water did drain when the black tank dump valve was pulled. This will happen if we use the kitchen sink or the shower, I know all one tank but did it to confirm that.

In the past if the gray over filled it would come out in the shower, lowest point in our MH. But it is not over filling.

Help, we have no clue to what could be happening. Anyone out there have any idea what could be happening

13 Replies

  • Our Monaco is the same way. Bathroom sink drains in to the black tank.
    Kitchen sink and shower in to the grey tank.
  • Many RVs, including mine, have the bathroom sink drain into the black tank. The reasoning is to be sure you have plenty of water in the black tank to prevent buildup of solids. I prefer it that way. Are you using too much water from the bathroom sink?
  • We have friends with a mid 90s Serengeti. The bathroom sink is plumbed into the black tank. What about a washer...do you have one, and does it go in the black tank?