Can you build an ADU in Ardsley, NY?

One-Family Residential District - An accessory building must keep the same front, side and rear setbacks shown for the district, and may abut the main building (§ 200-12).

Conservation or Clustered Housing District, Conservation or Clustered Housing District - A development here must be 8 to 12 contiguous acres with 200 ft of frontage on a major collector street, and the 12% building coverage is measured against the whole district rather than the lot.

• A buffer at least 75 ft deep runs inward from every property line, street lines included, and no building, parking area or use may sit in it, though driveways and walkways may cross it (§ 200-36).
• Assisted, independent and special needs living units come only by special permit and site plan approval of the Board of Trustees, on a site of at least 300,000 square feet.
• That special permit site must hold at least 1,800 square feet for every living unit and have 500 ft of frontage on a state highway.
• Buildings and parking on that site must stand 75 ft back from the state highway, 30 ft from any other road frontage and 25 ft from any other lot line.
• The number of dwelling units may not exceed the number of lots the land would yield if it were subdivided to the R-3 district standard of 7,500 square feet.
• At least 30% of the land must stay open space, no more than six may be attached or clustered together, and clustered structures must stand at least 30 ft apart.

One-Family Residential District - An accessory building must be set back at least 30 ft from the front, 20 ft from the side and 20 ft from the rear, and may abut the main building (§ 200-20).

One-Family Residential District - An accessory building must be set back at least 20 ft from the front, 15 ft from the side and 15 ft from the rear, and may abut the main building (§ 200-28).

Residence Office District - On site plan approval an office or studio, or a multifamily building, takes the General Business district standards instead: a lot of at least 5,000 square feet and a front yard of 10 ft, with side and rear yards of zero ft.

• A side or rear yard that is provided must still be at least 6 ft (§ 200-70B).
• The district's own rule keeps the R-3 district standards but takes height to 40 ft and four stories and building coverage to 40% (§ 200-64.1B).
• A multifamily building may put residential use on the ground floor, which the General Business district otherwise forbids (§ 200-64.1E).
• Site plan approval from the Board of Trustees is required for multifamily and nonresidential uses (§ 200-82F).
• A principal one-family building must cover at least 800 square feet of ground on one story, or 600 square feet on two, not counting garage area (§ 200-27).
• Lot area leaves out 75% of any wetland, water body or watercourse, and on a lot created after 2003 half of any steep slope as well (§ 200-2).

Residential District - The district publishes no lot minimum of its own: density is one dwelling unit for each 4,000 square feet of lot area. The 30 ft side and rear yards shown are the ones owed next to a residence district, and drop to 20 ft where the lot line adjoins a business district.

• A one-family house instead takes the R-3 district standards: a lot of at least 7,500 square feet, 60 ft wide, with 20 ft front and rear yards, 15 ft side yards and coverage up to 28%.
• A buffer of 10 ft next to a business district or 20 ft next to a residential district is required on top of the yards, unless the Board of Trustees accepts alternate screening (§ 200-29.1B(9)).
• Buildings must stand at least 15 ft apart and no building may exceed 8,000 square feet of gross floor area (§ 200-29.1B(4) and (5)).
• Site plan approval from the Board of Trustees is required before any use or development of land in the district (§ 200-29.1C).
• The R-4A overlay covers the same land and requires that at least 20% of the units in a new multifamily development be workforce housing and another 20% affordable.
• Lot area leaves out 75% of any wetland, water body or watercourse, and on a lot created after 2003 half of any steep slope as well (§ 200-2).

General Business District - A one-family house is held to the R-3 district standards rather than the figures shown: a lot of at least 7,500 square feet with 60 ft of street frontage, 20 ft front and rear yards, 15 ft side yards, a height limit of 30 ft and two stories, and coverage of up to 28%.

• No side or rear yard is required, but one that is provided must be at least 6 ft (§ 200-70B).
• The 65% coverage counts all principal and accessory buildings (§ 200-69).
• Where the lot abuts a lot in a residential district, the yard along that line must equal the yard that residential district requires, with 10 ft of it set aside for ornamental planting (§ 200-87).
• Where one side of a street between two intersecting streets is split between residential and business zoning, the business front yard must equal the residential front yard (§ 200-88).
• A nonresidential use over 20,000 square feet of floor area needs a special permit from the Board of Trustees (§ 200-65B(12)).
• Every plan, use and condition in the district needs site plan approval of the Board of Trustees after a public hearing (§ 200-82F).

Special Business District - A lot whose side yard borders a residence district must instead meet that residence district's own minimum side yard, if it is larger than 10 ft (§ 200-77).

Shopping Center Business District - A lot must be at least 4 acres, with coverage capped at 20% and height capped at 1 story and 25 ft (§ 200-80.1E).

• A side yard bordering a residence district must instead meet that residence district's own minimum width, if it is larger than 20 ft.