Can you build an ADU in Lewisboro, NY?

One-Family Residence District - Each new lot needs 40,000 sq ft of contiguous land likely to be buildable, at least 50 ft wide and clear of wetlands, watercourses, floodplain and slopes of 15% or more, and the house and any septic system must sit on it.

• The front yard is also at least 75 ft from the street center line.
• Each new lot must be able to contain a circle 200 ft in diameter (§ 220-25A).
• Where a new lot is deeper than 450 ft, its required lot area rises by the ratio of its actual depth to 450 ft (§ 220-25B).
• In an approved cluster development, lots may be reduced to the R-1A standards (further only with Town Board authorization), with no more lots than a conventional subdivision would yield.

One-Family Residence District - Each new lot needs 50,000 sq ft of contiguous land likely to be buildable, at least 50 ft wide and clear of wetlands, watercourses, floodplain and slopes of 15% or more, and the house and any septic system must sit on it.

• The front yard is also at least 75 ft from the street center line.
• Each new lot must be able to contain a circle 250 ft in diameter (§ 220-25A).
• Where a new lot is deeper than 700 ft, its required lot area rises by the ratio of its actual depth to 700 ft (§ 220-25B).
• In an approved cluster development, lots may be reduced to the R-1A standards (further only with Town Board authorization), with no more lots than a conventional subdivision would yield.

One-Family Residence District - Each new lot needs 20,000 sq ft of contiguous land likely to be buildable, at least 50 ft wide and clear of wetlands, watercourses, floodplain and slopes of 15% or more, and the house and any septic system must sit on it.

• The front yard is also at least 55 ft from the street center line.
• An accessory building no more than 12 ft high needs only 5 ft from any lot line in the rear yard.
• Each new lot must be able to contain a circle 100 ft in diameter (§ 220-25A).
• Where a new lot is deeper than 225 ft, its required lot area rises by the ratio of its actual depth to 225 ft (§ 220-25B).
• A lot in a cluster development must still meet at least the R-1A standards (§ 220-88B).

One-Family Residence District - Each new lot needs 35,000 sq ft of contiguous land likely to be buildable, at least 50 ft wide and clear of wetlands, watercourses, floodplain and slopes of 15% or more, and the house and any septic system must sit on it.

• The front yard is also at least 65 ft from the street center line.
• Each new lot must be able to contain a circle 150 ft in diameter (§ 220-25A).
• Where a new lot is deeper than 300 ft, its required lot area rises by the ratio of its actual depth to 300 ft (§ 220-25B).
• The R-1A standards are also the smallest a lot in a cluster development in any district may have, unless the Town Board authorizes a further reduction (§ 220-88B).

One-Family Residence District - Each new lot needs 10,000 sq ft of contiguous land likely to be buildable, at least 50 ft wide and clear of wetlands, watercourses, floodplain and slopes of 15% or more, and the house and any septic system must sit on it.

• The front yard is also at least 50 ft from the street center line.
• An accessory building no more than 12 ft high needs only 5 ft from any lot line in the rear yard.
• Each new lot must be able to contain a circle 75 ft in diameter (§ 220-25A).
• Where a new lot is deeper than 150 ft, its required lot area rises by the ratio of its actual depth to 150 ft (§ 220-25B).
• A lot in a cluster development must still meet at least the R-1A standards (§ 220-88B).

Two-Family Residence District - The figures shown apply to one-family and two-family dwellings alike. Each new lot needs 9,300 sq ft of contiguous land likely to be buildable, at least 50 ft wide and clear of wetlands, watercourses, floodplain and slopes of 15% or more.

• The house and any septic system must sit on that buildable land (§ 220-10E(2)).
• By special permit, an existing building on a lot of at least 0.60 acre may be converted to a multifamily dwelling of no more than four units, with ACARC review (§ 220-43.8).
• That conversion allows at most one density unit per 0.15 acre of net lot area, and needs two parking spaces per unit plus one for each unit with two or more bedrooms.
• The front yard is also at least 55 ft from the street center line.
• An accessory building no more than 12 ft high needs only 5 ft from any lot line in the rear yard.
• Each new lot must be able to contain a circle 75 ft in diameter (§ 220-25A).

Multifamily Residence District - On a lot within and served by a Town of Lewisboro public water and sewer district, the minimum lot area is 15,000 sq ft. Multifamily dwellings need site plan approval and may not exceed four density units per acre of net lot area.

• The Planning Board may raise that density by up to 50% where at least one third of the added units are affordable units (§ 220-26B(2)).
• Within a density transition area along a single-family district boundary, as deep as that district's minimum lot width, density may not exceed one density unit per acre.
• At least 30% of the gross lot area stays permanent open space, free of buildings and parking, plus at least 300 sq ft of common recreation area per density unit (§ 220-26D).
• Along a line shared with an adjoining single-family residence district, each yard must be at least twice the setback that district requires from that line, and never less than the figures shown.
• A multifamily or nonresidential property keeps a natural or planted buffer 30 ft wide along lines that abut or face across a street land in a residence district (§ 220-15C).
• The front yard is also at least 75 ft from the street center line.

Two-Family Residence District - The figures shown apply to one-family and two-family dwellings alike. Each new lot needs 7,125 sq ft of contiguous land likely to be buildable, at least 50 ft wide and clear of wetlands, watercourses, floodplain and slopes of 15% or more.

• The house and any septic system must sit on that buildable land (§ 220-10E(2)).
• By special permit, an existing building on a lot of at least 0.60 acre may be converted to a multifamily dwelling of no more than four units, with ACARC review (§ 220-43.8).
• That conversion allows at most one density unit per 0.15 acre of net lot area, and needs two parking spaces per unit plus one for each unit with two or more bedrooms.
• The front yard is also at least 50 ft from the street center line.
• An accessory building no more than 12 ft high needs only 5 ft from any lot line in the rear yard.
• Each new lot must be able to contain a circle 60 ft in diameter (§ 220-25A).

Campus Commercial District - Each lot needs frontage on a state highway, with no access drive to local streets. No site improvement may be closer than 200 ft to a residence district boundary, and a 200 ft buffer inside the lot along every line abutting one stays natural.

• The 60 ft height applies to a principal building the Planning Board finds reduces site and visual impacts, on a site of at least twice the minimum lot area (§ 220-24B(3)(d)).
• That building also needs at least 90% of required parking inside it below adjacent grade, and a roof no higher than elevation 370 on the USGS datum.
• Site coverage counts all buildings, structures, parking and loading areas, drives, patios, terraces, walks and other improved surfaces.
• The floor area ratio is figured on net lot area, deducting 0.75 of the area of wetlands, watercourses and steep slopes.
• The front yard is also at least 175 ft from the street center line.
• Multifamily dwellings need site plan approval and may not exceed four density units per acre of net lot area (§ 220-26B(1)).

General Business District, Retail Business District - No single structure may cover more than 10,000 sq ft. Where a lot line abuts land in a residence district, that residence district's setbacks govern.

• Site coverage counts all buildings, structures, parking and loading areas, drives, patios, terraces, walks and other improved surfaces.
• A multifamily or nonresidential property keeps a natural or planted buffer 30 ft wide along lines that abut or face across a street land in a residence district (§ 220-15C).
• That buffer is 15 ft wide along lines abutting a nonresidence district and 20 ft wide across a street from one.
• Multifamily dwellings need site plan approval and may not exceed four density units per acre of net lot area (§ 220-26B(1)).
• A multifamily site needs at least two acres of gross lot area. Within a Town public water and sewer district that drops to 15,000 sq ft, but the stricter 1/2 acre district minimum governs.
• The front yard is also at least 45 ft from the street center line.

Service Utility District - No site improvement may be closer than 100 ft to a residence district, and a perimeter buffer 100 ft wide, kept in its natural state, also applies (§ 220-24C(4)).

• The front yard is also at least 175 ft from the street center line.
• Site coverage counts all buildings, structures, parking and loading areas, drives, patios, terraces, walks and other improved surfaces.
• A multifamily or nonresidential property keeps a natural or planted buffer 30 ft wide along lines that abut or face across a street land in a residence district (§ 220-15C).
• Multifamily dwellings need site plan approval and may not exceed four density units per acre of net lot area (§ 220-26B(1)).
• The Planning Board may raise that density by up to 50% where at least one third of the added units are affordable units (§ 220-26B(2)).