Don’t bother with permits for an outdoor bathroom.
Here is inexpensive design for an outdoor shower/toilet combo for parties.It is easy to get up and down and since most parties are on weekends, code enforcement won’t be working. If anyone wants the design, pm me.
Stand a piece of plywood on end perpendicular to the earth, long edges up. Support it with t-posts and tie wraps… or wire. Hang a hose with a trigger type nozzle over the top and let the nozzle rest against the plywood at about 72″ from grade. Dig hole on the other side of the plywood. Save the material from the excavation. The hole should be at a depth reasonable to accommodate the size and duration of party you anticipate (usually this would be the more private elevation of project). Leave a bottle liquid soap and a roll of hygienic paper in the vicinity.
For a more “high end” version locate a soap dish, towel bar and toilet paper holder on the plywood according to a layout that suits you.
There is a version that includes a solar heated shower too.
