by 48Rob » Fri May 14, 2010 6:57 am
Mike,
The gray water tank is generally offset from the shower pan.
The shower pan should have a trap under it, and then be routed to the tank.
If you have a kitchen and or bathroom sink, they too would be connected to the drain line before dropping into the tank.
Black water tanks do have the toilet mounted directly over the tank, generally the shallow end, and use a fitting that allows adjustment between the flange on the floor and the tank, as the toilet is not usually "mounted" directly to the tank.
Having the straight drop allows for inserting a cleaning wand into the tank for rinsing.
There is no trap on the toilet, just a blade valve, though the system should be designed with a vent to take odors up and away from the tank so you don't have to hold your nose each time you flush.
Also, most plumb their tanks so the gray water tank is slightly higher than the black water tank, and connect the two with valves, so that after the black water tank is emptied, the gray water tank can "flush" the black water tank.
Rob
Waiting for "someday" will leave you on your deathbed wondering why you didn't just rearrange your priorities and enjoy the time you had, instead of waiting for a "better" time to come along...