What are the requirements for an ADU in Ferndale?

Section 5.01 sets the conditions. An accessory dwelling is permitted by right in R-1, R-2, MXD-1, and MXD-2 (Section 2.05) if it meets these standards:

• Lot. Allowed only on a lot with an existing one-, two-, or three-unit dwelling (Section 5.01.A).
• Utilities. Must connect to city-approved water and sewer (Section 5.01.B).
• Footprint. May not exceed the principal structure's footprint or 20 percent of the lot, whichever is less (Section 5.01.C). Caution: the published text reads "20% of the of the lot" and the table header mislabels the figure, so confirm the cap with the city at 248-336-4370.
• Height and placement. Maximum 25 feet tall, not in the front yard, with 5 foot side and rear setbacks (Section 5.01.C).

Review is administrative through the Building Department (Section 9.07). There is no owner-occupancy rule and no ADU parking requirement.