Farmhouse without plumbing until spring 2027: one porta potty enough?

One unit can work for a family of four, but five months is long enough that the real question is comfort and winter, not capacity. Nothing in OSHA or ADA sets a household number because those rules cover workplaces and public facilities, so this is your call.

What made our remodel bearable was treating the unit like a bathroom we had to manage. Keep spare paper and hand sanitizer inside, wipe the seat daily, and ask the provider to set the service visits around how many people actually use it, since a full-time household fills the tank faster than a jobsite crew that leaves at 4pm. Tell them up front it is four people living there so the schedule fits.

The bigger issue is cold. A deluxe unit with a sink has a fresh water tank that can freeze, so ask the provider how they handle that before you pay for the upgrade. A plain standard unit has no water to freeze and gets through a winter more easily.

A trailer is probably overkill unless you need a shower or sink indoors. Kids using the unit at night is the part families complain about most, so put a light on the path and keep the gravel clear.