Cedar 4" x 4"s scewed together with deck screws, attached to the floor with angle brackets.
The support platform for the tub was made from materials from our box garden. The cutout outlined on the right side will accommodate the P-trap plumbing. The kitchen counter/sink unit is on the right.
Rub-a-dub, baby. :-)
The pipe from the P-trap will drop down directly into the graywater tank.