For the purposes of assessing a per-unit impact fee to an ADU that is 750 square feet or larger on a Lot with a multifamily dwelling structure, how is the square footage of the primary residence determined?

The fee must be proportional to the average size of all dwelling units on the Lot. Floor plans showing the sizes of all units may be required to make this determination. An applicant may  choose to pay the full fee in lieu of providing these plans.