What it costs to build an ADU in Somers, NY

Residence R120 - Each single-family lot created by subdivision must contain a contiguous buildable area of 40,000 sq ft, or 20,000 sq ft with community sewer and community water, at least 50 ft across in every direction and free of wetlands, 100-year floodplain and slopes of 25% or more.

• Lot area excludes 75% of any wetlands, 100-year floodplain and slopes of 25% or more (§ 170-58.4A).
• A conservation subdivision of a parcel of 12 acres or more may use lots of 60,000 sq ft and 150 ft wide, at the Planning Board's discretion, with no more lots than a conventional layout would yield.
• The Planning Board may reduce frontage to one third of the width on a lot fronting a permanent turnaround, if the full width is met at the front yard setback line.
• Height is measured to the midpoint of a sloped roof, and a building must be at least 1 story and 13 ft to the highest point of the roof.
• Accessory buildings are held to 1 1/2 stories and 15 ft, and one not within or attached to the principal building sits at least 15 ft from the side and rear lot lines.
• A front yard need be no deeper than the average of the front yards of the adjoining houses (§ 170-48A).

Residence R80 - Each single-family lot created by subdivision must contain a contiguous buildable area of 30,000 sq ft, or 15,000 sq ft with community sewer and community water, at least 50 ft across in every direction and free of wetlands, 100-year floodplain and slopes of 25% or more.

• Lot area excludes 75% of any wetlands, 100-year floodplain and slopes of 25% or more (§ 170-58.4A).
• A conservation subdivision of a parcel of 12 acres or more may use lots of 40,000 sq ft and 125 ft wide, at the Planning Board's discretion, with no more lots than a conventional layout would yield.
• The Planning Board may reduce frontage to one third of the width on a lot fronting a permanent turnaround, if the full width is met at the front yard setback line.
• Height is measured to the midpoint of a sloped roof, and a building must be at least 1 story and 13 ft to the highest point of the roof.
• Accessory buildings are held to 1 1/2 stories and 15 ft, and one not within or attached to the principal building sits at least 15 ft from the side and rear lot lines.
• A front yard need be no deeper than the average of the front yards of the adjoining houses (§ 170-48A).

Designed Residential Development - A designed residential development needs at least 500 acres of contiguous land and Town Board approval in the R-120, R-80 or R-40 district. Unless approved before § 170-12 took effect, its density units may not exceed the one-family houses a conventional subdivision would yield.

• Its own standards replace the schedule's lot size, coverage, yard, separation and height rules, so individual lots have no minimum size and there is no coverage cap.
• A single-family detached house sits at least 40 ft from the edge of a Class A road right-of-way, 30 ft from the center line of a Class B road and 50 ft from the development's outside perimeter.
• Other principal structures need 40, 30 and 60 ft from those lines, and accessory structures 20, 20 and 30 ft (§ 170-12D(4)(b)).
• At least a third of the gross acreage must be recreation land or natural open space owned in common (§ 170-12D(2)).
• Buildings must stand apart by at least half the height of the taller one and never less than 10 ft.
• Wastewater treatment facilities sit at least 300 ft from the perimeter unless the adjoining owners agree of record and the Planning Board approves.

Residence R40 - Each single-family lot created by subdivision must contain a contiguous buildable area of 20,000 sq ft, or 10,000 sq ft with community sewer and community water, at least 50 ft across in every direction and free of wetlands, 100-year floodplain and slopes of 25% or more.

• Lot area excludes 75% of any wetlands, 100-year floodplain and slopes of 25% or more (§ 170-58.4A).
• A conservation subdivision of a parcel of 12 acres or more may use lots of 25,000 sq ft and 100 ft wide, at the Planning Board's discretion, with no more lots than a conventional layout would yield.
• The Planning Board may reduce frontage to one third of the width on a lot fronting a permanent turnaround, if the full width is met at the front yard setback line.
• Height is measured to the midpoint of a sloped roof, and a building must be at least 1 story and 13 ft to the highest point of the roof.
• Accessory buildings are held to 1 1/2 stories and 15 ft, and one not within or attached to the principal building sits at least 15 ft from the side and rear lot lines.
• A front yard need be no deeper than the average of the front yards of the adjoining houses (§ 170-48A).

Multifamily Residence Hamlet - The district is created by Town Board rezoning, only on land within public water and sewer districts. The 10 acres is the minimum for the development as a whole, and density is capped at an average of two density units per acre of net land area.

• A density unit is one single-family dwelling or one unit of four or more bedrooms, 1.5 three-bedroom units, two two-bedroom units or 2.5 units of one bedroom or less.
• The Town Board may raise the basic density by up to 50% for affordable units (§ 170-13A(5)), and a share of the basic density must be affordable (§ 170-13A(18)).
• Coverage is measured against net land area, which excludes 75% of wetlands, floodplain and very steep slopes; the 35% cap counts buildings plus paved roads, driveways and parking.
• All buildings sit at least 100 ft from a lot line shared with land in a single-family residence district; the Planning Board may reduce the building setbacks where their purpose is met.
• A buffer at least 30 ft wide, left natural and planted with evergreens, runs along lines that abut or face a residence district.
• Minimum gross floor area per unit is 300 sq ft for an efficiency, 500 for one bedroom, 700 for two, 900 for three and 1,100 for four.

Residence R10 - Each single-family lot created by subdivision must contain a contiguous buildable area of 10,000 sq ft, or 5,000 sq ft with community sewer and community water, at least 50 ft across in every direction and free of wetlands, 100-year floodplain and slopes of 25% or more.

• Lot area excludes 75% of any wetlands, 100-year floodplain and slopes of 25% or more (§ 170-58.4A).
• Conservation subdivisions are not available in this district (§ 170-13.2B).
• The Planning Board may reduce frontage to one third of the width on a lot fronting a permanent turnaround, if the full width is met at the front yard setback line.
• Height is measured to the midpoint of a sloped roof, and a building must be at least 1 story and 13 ft to the highest point of the roof.
• Accessory buildings are held to 1 1/2 stories and 15 ft, and one not within or attached to the principal building sits at least 5 ft from the side and rear lot lines.
• A front yard need be no deeper than the average of the front yards of the adjoining houses (§ 170-48A).

Corporate Research/Office - Principal buildings are limited to 65 ft above the highest finished grade on the property and never more than 150 ft above the adjacent finished grade. Within 500 ft of an abutting residential property or public highway they must also stay under a plane rising at seven degrees.

• The figures shown apply to office buildings and their accessory uses.
• Accessory buildings may cover a further 2% of the lot (§ 170-32B).
• Every yard is kept as a natural or landscaped buffer, apart from entry drives and minor structures such as gatehouses shown on an approved site plan (§ 170-32D).
• Accessory structures are held to 30 ft within 500 ft of an abutting residential property or public highway and to 15 ft within 100 ft of any property boundary (§ 170-32G).
• Floor area ratio and building coverage exclude 75% of wetlands, floodplain and very steep slopes (§ 170-58.4C).
• Any use permitted in the R-80 district is also permitted here, subject to the R-80 limitations (§ 170-30A).

Office Business - No principal building may stand on a portion of less than 100 contiguous acres, though a lot may be divided by a street it fronts on. Accessory uses may sit in the yards but no closer than 100 ft to a street or to property in a residence district.

• That 100 ft strip stays a natural or landscaped buffer.
• Accessory buildings may cover a further 2% of the lot (§ 170-28B).
• § 170-47D allows 10 ft and one story more where the setbacks from streets and property lines grow by 10 ft for each foot of added height.
• Accessory structures within 500 ft of a property boundary are held to 2 stories and 30 ft, and within 100 ft of a street or residence district property to 1 story and 15 ft.
• The figures shown apply to office buildings and their accessory uses.
• Any use permitted in the R-80 district is also permitted here, subject to the R-80 limitations (§ 170-26A).

Community Shopping - A 0 ft side yard needs the adjoining nonresidential-district owner to agree to a common wall; otherwise it is at least 25 ft. Abutting a residence district, the side yard is at least 40 ft and the rear at least 60 ft, each with at least 40 ft landscaped.

• Principal buildings may cover 18% of the lot and accessory buildings 1%.
• Floor area ratio is 0.20 for all uses combined, of which nonresidential floor area may reach no more than 0.18.
• The code sets no minimum lot area or width for this district.
• The front yard is measured from the existing or planned future right-of-way, whichever is more restrictive.
• Accessory buildings are held to one storey and 15 ft.
• The Planning Board may let architectural features exceed the height limits.

Neighborhood Shopping - A 0 ft side yard needs the adjoining nonresidential-district owner to agree to a common wall; otherwise it is at least 25 ft. Abutting a residence district, the side yard is at least 40 ft, and the side and rear yards each need a landscaped buffer at least 20 ft wide.

• No building footprint may exceed 10,000 sq ft unless the Planning Board grants a special exception use permit for a use serving a special community need (§ 170-20.3E).
• Floor area ratio is 0.25 for all uses combined, of which nonresidential floor area may reach no more than 0.18.
• With public water and sewer and at least half the residential units affordable, the Town Board may allow a combined FAR of up to 0.4, nonresidential at most 0.18, and 3 stories or 50 ft (§ 170-20.4B).
• A mixed commercial and affordable residential project needs at least eight acres with public water and sewer, less than 500 ft of frontage on a major road, and at least half its units affordable.
• Principal buildings may cover 15% of the lot and accessory buildings 1%.
• The code sets no minimum lot area or width for this district.

Office and Light Industry - A vegetated buffer at least 50 ft wide is required along any residentially zoned boundary, and side and rear yards there are measured from the edge of that buffer rather than the property line.

• Parking sits at least 20 ft from side and rear property lines and 40 ft from the front property line, and never in the buffer (§ 170-24.5K).
• A self-storage facility may cover 25% of the lot with a floor area ratio of 0.45 (§ 170-24.2K).
• The front yard is measured from the existing or planned future right-of-way, whichever is more restrictive, and stays landscaped or natural apart from access drives and walkways.
• Floor area ratio and building coverage exclude 75% of wetlands, floodplain and very steep slopes (§ 170-58.4C).

Business Historic Preservation - No principal building footprint may exceed 3,000 sq ft. The front yard is at least 20 ft and at most 40 ft, and the Planning Board may extend the maximum to keep natural features.

• Floor area ratio for all uses is 0.20 under 12,000 sq ft, 0.18 from 12,000 sq ft to under half an acre, 0.16 from half an acre to under one acre and 0.14 at one acre or more (§ 170-17.1E).
• For nonresidential uses the ratio is 0.12, 0.10, 0.09 and 0.08 on the same lot-size bands.
• Lot area excludes 75% of wetlands, floodplain and very steep slopes, and places of worship and schools need a lot of at least two acres (§ 170-15.1A).
• An accessory building footprint is limited to half the smallest principal building or 750 sq ft, whichever is less.
• The 10% principal and 1% accessory building coverage are each reduced by the footprint of a significant building that is removed or altered.
• Principal buildings must reach at least 1 1/2 stories and 15 ft.

Planned Hamlet - Multifamily residences must be part of every development, with at least 15% of the permitted multifamily units affordable. The figures shown apply to the PH parcel as a whole, and lots within it follow the approved site master plan.

• Floor area ratio is 0.20 for all uses together, before any incentive residential density the Town Board grants (§ 170-23.4B).
• No single listed use category may exceed 0.04, except multifamily residences, which must reach at least 0.04 and may reach 0.06 plus any incentive density.
• Restaurants, taverns, convenience stores and specialty shops are held to a floor area ratio of 0.01.
• The code sets no minimum lot area or width for this district.
• Beside a residence district the side yard is 40 ft, all of it landscaped buffer, and the rear yard rises to 60 ft with 40 ft of landscaped buffer.
• Beside a nonresidential district the side yard may be zero where both neighbors agree to build to a common wall on the shared line.

Beach-Community House - BC permits only the uses and structures that received a certificate of occupancy within 30 days of the chapter's effective date, plus facilities incidental to them that the Board of Appeals permits (§ 170-25).

• The district has no lot, yard, coverage or height standard of its own.

Multifamily Residence Baldwin Place - To be designated, a tract must carry underlying R-40 or R-80 zoning and front on Route 6 within 2,000 ft of its intersection with Mahopac Avenue. The 10 acres is the minimum for the whole development, and density averages at most three density units per acre of net land area.

• The district is created by Town Board rezoning on a preliminary development concept plan, only on land within public water and sewer districts.
• A density unit is one single-family dwelling or one unit of four or more bedrooms, 1.5 three-bedroom units, two two-bedroom units or 2.5 units of one bedroom or less.
• The Town Board may raise the basic density by up to 50% for affordable units (§ 170-13A(5)), and a share of the basic density must be affordable (§ 170-13A(18)).
• Coverage is measured against net land area, which excludes 75% of wetlands, floodplain and very steep slopes; the 40% cap counts buildings plus paved roads, driveways and parking.
• All buildings sit at least 100 ft from a lot line shared with land in a single-family residence district; the Planning Board may reduce the building setbacks where their purpose is met.
• A buffer at least 30 ft wide, left natural and planted with evergreens, runs along lines that abut or face a residence district.