Black/Grey tanks
Just an idle question ? Why do RV's have separate black and grey tanks. I have a septic system at home; black and grey wastes flow through the same pipes into the same tank; eventually to the field....
Forum Discussion
There are still some (albeit relatively few) places where it is legal and reasonable to dump/dribble gray water on the ground or into a dry well, but not black water.
When connected to a full hookup site, it's sometimes convenient to leave the gray water partly or entirely open and not have to worry about how full that tank is. This should not be done with the black tank since it would tend to leave the solids piling up without sufficient liquid to have them rinse away as desired. A house doesn't have this problem partly because a lot more water is used in flushing household toilets than RV toilets (and also partly because septic tanks operate on different principles than holding tanks).
Finally, it may have something to do with people not really liking black water overflowing into their shower pan when the tank fills up.
When connected to a full hookup site, it's sometimes convenient to leave the gray water partly or entirely open and not have to worry about how full that tank is. This should not be done with the black tank since it would tend to leave the solids piling up without sufficient liquid to have them rinse away as desired. A house doesn't have this problem partly because a lot more water is used in flushing household toilets than RV toilets (and also partly because septic tanks operate on different principles than holding tanks).
Finally, it may have something to do with people not really liking black water overflowing into their shower pan when the tank fills up.
