What it costs to build an ADU in North Salem, NY

Low Density Residential District - The lot size, width and yards shown are for a single-family detached house, which also needs at least 150 ft of street frontage. Other uses in R-2 owe different yards.

• An average density subdivision, which the Planning Board allows only where it finds cluster feasible and appropriate, cuts the minimum lot to 0.25 acre with 100 feet of width.
• Attached houses are allowed only as part of an average density subdivision, need a special permit, and their lot width drops to 60 feet.
• Multifamily dwellings for elderly and handicapped persons need a special permit and at least 6 acres with 300 feet of width.
• Not more than 50% of land under water, in a freshwater wetland, in the 100-year floodplain, in an overhead utility easement or on unexcavated slopes over 25% counts toward the minimum lot area.
• A subdivision of 10 or more lots must provide an affordable housing dwelling on 10% of the approved lots.
• The Planning Board may cut the required 150 feet of frontage to half of that on a cul-de-sac or a street whose center-line curve radius is 100 feet or less, reducing lot width in proportion.

Rural Density Residential District - The lot size, width and yards shown are for a single-family detached house, which also needs at least 150 ft of street frontage. Other uses in R-4 owe different yards.

• An average density subdivision, which the Planning Board allows only where it finds cluster feasible and appropriate, cuts the minimum lot to 0.5 acre with 100 feet of width.
• Attached houses are allowed only as part of an average density subdivision, need a special permit, and their lot width drops to 60 feet.
• Multifamily dwellings for elderly and handicapped persons need a special permit and at least 10 acres with 400 feet of width.
• Not more than 50% of land under water, in a freshwater wetland, in the 100-year floodplain, in an overhead utility easement or on unexcavated slopes over 25% counts toward the minimum lot area.
• A subdivision of 10 or more lots must provide an affordable housing dwelling on 10% of the approved lots, or two affordable rental accessory apartments in place of one such house.
• The Planning Board may cut the required 150 feet of frontage to half of that on a cul-de-sac or a street whose center-line curve radius is 100 feet or less, reducing lot width in proportion.

Medium Density Residential District - The lot size, width and yards shown are for a single-family detached house, which also needs at least 120 ft of street frontage. Other uses in R-1 owe different yards.

• An average density subdivision follows the R-2 standards, cutting the minimum lot to 0.25 acre, and the Planning Board allows it only where it finds cluster feasible and appropriate.
• Attached houses are allowed only as part of an average density subdivision, need a special permit, and their lot width drops to 60 feet.
• Multifamily dwellings for elderly and handicapped persons need a special permit and at least 6 acres with 300 feet of width.
• Not more than 50% of land under water, in a freshwater wetland, in the 100-year floodplain, in an overhead utility easement or on unexcavated slopes over 25% counts toward the minimum lot area.
• A subdivision of 10 or more lots must provide an affordable housing dwelling on 10% of the approved lots.
• The Planning Board may cut the required 120 feet of frontage to half of that on a cul-de-sac or a street whose center-line curve radius is 100 feet or less, reducing lot width in proportion.

Medium Density Residential District - The lot size, width and yards shown are for a single-family detached house, which also needs at least 80 ft of street frontage. Other uses in R-1/2 owe different yards.

• Multifamily dwellings for elderly and handicapped persons need a special permit and at least 6 acres with 300 feet of width.
• Average density, the cluster option, is not allowed in this district.
• Not more than 50% of land under water, in a freshwater wetland, in the 100-year floodplain or in an overhead utility easement counts toward the minimum lot area.
• Not more than 25% of land on unexcavated slopes over 25% counts toward the minimum lot area.
• A subdivision of 10 or more lots must provide an affordable housing dwelling on 10% of the approved lots.
• The Planning Board may cut the required 80 feet of frontage to half of that on a cul-de-sac or a street whose center-line curve radius is 100 feet or less, reducing lot width in proportion.

Planned Development-Continuing Care Retirement Community District - The lot and yard figures describe the outside boundary of the whole development, and density is capped at six dwelling units for independent living or assisted living rooms per acre. The site needs frontage on a state or county highway and central sewage and water.

• Detached single-family structures on individual lots need 10 feet of front, side and rear yard, and on commonly held land must stand 20 feet apart at the side and 30 feet at the rear.
• Multifamily structures of three or more units must stand 1 1/2 times the height of the taller building apart.
• At least 10% of the independent living dwellings and assisted living rooms must be affordable housing.
• Required street frontage is a separate minimum of 200 feet.
• Medium-density single-family houses, attached or detached, need a special permit, are capped at four dwellings an acre, and at least a fifth of them must be affordable housing.
• Accessory uses such as day care, shops, restaurants and clinics may fill no more than 5% of the site's gross floor area, and all accessory uses together no more than 30%.

Medium-High Density Residential District - The lot size, width and yards shown are for a single-family detached house, which also needs at least 75 ft of street frontage. Other uses in R-1/4 owe different yards.

• Multifamily dwellings need at least 5 acres with 300 feet of width and a 75 foot front yard.
• For those multifamily dwellings at least a fifth of the units must be affordable housing, no more than a tenth may have three or more bedrooms, and a building holds between two and eight units.
• Multifamily dwellings for elderly and handicapped persons need at least 10 acres with 400 feet of width.
• Attached houses need a special permit, on a lot with 150 feet of width and a 35 foot front yard.
• Not more than 50% of land under water, in a freshwater wetland, in the 100-year floodplain or in an overhead utility easement counts toward the minimum lot area.
• Not more than 25% of land on unexcavated slopes over 25% counts toward the minimum lot area.

Residential-Multifamily/Medium-Density District - These lot and yard figures apply to the outside boundary of the whole development, not the individual lots inside it: a detached house or a structure of no more than two attached houses, on its own lot, needs only 10 feet of front, side and rear yard.

• On commonly or cooperatively held land those structures must stand 20 feet apart at the side, 30 feet at the rear, and 15 feet back from the edge of the traveled way.
• Multifamily structures of three or more units must stand 1 1/2 times the height of the taller building apart and 20 feet back from the edge of the traveled way.
• Multifamily housing for senior citizens and disabled persons is allowed at a higher density, six units an acre.
• A site here may be no larger than 50 acres.
• At least 20% of the units must be affordable housing.
• Development is contingent on common or central water and sewage facilities, whose aboveground structures must sit at least 100 feet from every external boundary of the site.

Residential-Multifamily/High-Density District - These lot and yard figures apply to the outside boundary of the whole development, not the individual lots inside it: a detached house or a structure of no more than two attached houses, on its own lot, needs only 10 feet of front, side and rear yard.

• On commonly or cooperatively held land those structures must stand 20 feet apart at the side, 30 feet at the rear, and 15 feet back from the edge of the traveled way.
• Multifamily structures of three or more units must stand 1 1/2 times the height of the taller building apart and 20 feet back from the edge of the traveled way.
• Multifamily housing for senior citizens and disabled persons is allowed at a higher density, eight units an acre, and needs a Town Board special permit.
• A site here may be no larger than 50 acres.
• At least 20% of the units must be affordable housing.
• Development is contingent on common or central water and sewage facilities, whose aboveground structures must sit at least 100 feet from every external boundary of the site.

Research-Office District - The lot and yard figures apply to the medical and dental offices, business and professional offices, banks and studio instruction businesses permitted by right here, which also need at least 120 feet of street frontage. A different use can owe different figures.

• Libraries, museums, art studios and galleries are permitted by right but need a minimum lot of 2 acres with a 200 foot lot width and a 50 foot front yard.
• A laboratory or research facility is a Planning Board conditional use and needs a minimum lot of 160,000 square feet with a 300 foot lot width and a 75 foot front yard.
• Indoor recreation, indoor light industry, veterinary offices and animal hospitals, tradesman offices and day-care centers are conditional uses on the figures shown.
• The Planning Board may modify side and rear yards for nonresidential uses with site development plan approval, except where the lot abuts a residential district or use.
• The Planning Board may cut the required frontage to half of that on a cul-de-sac or a tight curve, reducing lot width in proportion.

General Business District - The lot and yard figures cover almost every use permitted by right here, including retail stores, offices, banks and restaurants, each capped at 3,500 square feet of floor area for a single proprietorship.

• Multifamily dwellings need a special permit, are capped at four dwellings an acre, and need a 300 foot lot width and a 75 foot front yard.
• Where at least a third of the units are affordable housing, development coverage may rise to 60%, building coverage to 25% and the floor area ratio to 0.40.
• A multifamily building of only affordable housing dwellings is a Planning Board conditional use, on a minimum lot of 5,000 square feet with a 160,000 square foot maximum.
• Libraries, museums, art studios and galleries need a minimum lot of 20,000 square feet with a 100 foot lot width and a 30 foot front yard.
• For multifamily dwellings at least 20% of the units must be affordable housing, no more than a tenth may have three or more bedrooms, and a building holds between two and eight units.
• Street frontage is a separate minimum of 120 feet, which the Planning Board may cut to half of that on a cul-de-sac or a tight curve.

Neighborhood Business District - The lot and yard figures cover the retail stores, personal service businesses, offices, banks and barbershops permitted by right here, each capped at 3,500 square feet of floor area for a single proprietorship.

• Medical and dental offices or clinics, and libraries, museums, art studios and galleries, need a minimum lot of 20,000 square feet with a 100 foot lot width and a 30 foot front yard.
• Restaurants and other seated food service, fire or ambulance stations and shops selling antiques, clothing, furniture or hardware need a minimum lot of 40,000 square feet with a 150 foot lot width.
• Accessory seasonal outdoor restaurant seating is a Planning Board conditional use, on a minimum lot of 10,000 square feet with a 60 foot lot width and a 30 foot front yard.
• Required street frontage is a separate minimum of 50 feet, which the Planning Board may cut to half of that on a cul-de-sac or a tight curve, reducing lot width in proportion.

Professional Office District - The lot and yard figures apply to the offices, banks, restaurants, libraries and personal service businesses permitted by right here. A single-family detached house is also permitted by right, on a minimum lot of 0.5 acre.

• That house needs a lot at least 100 feet wide, a front yard of at least 30 feet, side yards of at least 15 feet and 40 feet combined, and a rear yard of at least 35 feet.
• Building coverage for that house is capped at 10% and its density at 2 dwellings an acre.
• Fire or ambulance stations, private schools, nursery schools, day-care centers, bed-and-breakfast establishments and membership clubs follow their own figures, not the district's.
• Required street frontage is a separate minimum of 75 feet, which the Planning Board may cut to half of that on a cul-de-sac or a tight curve, reducing lot width in proportion.
• At most 50% of land under water, in a freshwater wetland, in the 100-year floodplain, in an overhead utility easement or on unexcavated slopes over 25% counts toward a residential minimum lot area.
• Average density, the cluster option, is not allowed here.