Can you build an ADU in Sweden, NY?

One-Family Residential, no sewer and/or water - The lot minimum turns on septic and water: 40,000 sq ft with public water and an in-ground or modified raised fill system, 150,000 sq ft where an aboveground modified raised fill system is needed, and five acres where a full raised fill system is required.

• Lot area is net: it excludes designated wetlands and their one-hundred-foot buffers, highway rights-of-way, reserved strips and the driveway land on a flag lot (§ 175-36D(2)(d)).
• The 40,000 sq ft step takes 150 ft of width, and the 150,000 sq ft and five-acre steps take 260 ft.
• Road frontage stays 60 ft at every step, and width is measured at the front line of the house, so a lot may neck down at the road if it opens to the required width where the house sits.
• An aboveground modified raised fill system has its own setbacks: 75 ft to the sides and 50 ft front and rear on a 150,000 sq ft lot, and 25 ft to every property line on a 40,000 sq ft lot.
• Minimum building area is 710 sq ft for a one-and-one-half-storey, split-level or raised ranch and 576 sq ft for a two-storey.
• Each dwelling unit needs one habitable room per resident of at least 120 sq ft, at least 70 sq ft per person in a bedroom, and one full bathroom for each eight residents.

One-Family Residential within a sanitary sewer district - This district is mapped as a sanitary sewer district, so whether a parcel is here or in R1-2 comes from the Zoning Map, not from whether the lot is connected. The same one-family house needs 15,000 sq ft here and 80,000 sq ft in R1-2.

• On an arterial highway the front setback rises to 75 ft.
• Width is measured at the front line of the house, and only 60 ft of road frontage is required.
• Minimum building area is 710 sq ft for a one-and-one-half-storey, split-level or raised ranch and 576 sq ft for a two-storey.
• Each dwelling unit needs one habitable room per resident of at least 120 sq ft, at least 70 sq ft per person in a bedroom, and one full bathroom for each eight residents.

One-Family Residential within a sanitary sewer district - Every property line that abuts a street must meet the front setback, so a corner lot owes 40 ft on both frontages. On an arterial highway the front setback rises to 75 ft.

• Lot depth may be reduced by up to 10%, to 108 ft, provided the minimum lot area is still maintained.
• Minimum building area is 710 sq ft for a one-and-one-half-storey, split-level or raised ranch and 576 sq ft for a two-storey.
• Each dwelling unit needs one habitable room per resident of at least 120 sq ft, at least 70 sq ft per person in a bedroom, and one full bathroom for each eight residents.

Multiple Residence - At least 25% of the total lot area must stay open and unused, and it may not be paved or used for parking, storage or buildings. Parking is not counted in the 50% building coverage, so the site plan splits three ways between building, parking and open space.

• The district states no minimum lot area, so yield comes from the 12 units per acre density cap and the 50% coverage cap together.
• Parking is two spaces per apartment in buildings over four units, and three per unit for town homes, patio homes, condominiums, duplexes and quadplexes, at least one in an enclosed garage.
• Buildings on the same site must stand 20 ft apart.
• The open area may include landscaping, stormwater retention or detention, underground utilities, screening and fencing.
• Multiple dwellings, town homes, patio homes, condominiums and zero lot-line duplexes and quadplexes are permitted by right.