What you need to know 

Orleans currently has restrictive rules associated with adding an ADU to a single family lot. The town does not allow additions or new construction unless it will have a minimal impact on the existing footprint of the existing structures.

Construction Rules

• The ADU must must be less than eight hundred (800) square feet.

• Additions cannot increase lot coverage by more than two percent (2%) of the lot area.

• The lot must be at least 40,000 SF of contiguous buildable upland.

• One of the two units must be owner occupied year round.

See the full text here: Zoning Ordinance 164-40 Uncommon housing.