Can you build an ADU in Putnam Valley, NY?

Preservation District - Single-family dwellings are not among the permitted uses in PD. The 10 acre minimum is a net area, gross lot area less roads, rights-of-way and easements, so deed acreage overstates what counts toward it.

• The 2% figure is a maximum impervious cover, the complement of a required 98% minimum open area, and it counts buildings, structures, paved areas and other impervious surfaces.
• Buildings are also capped at 50 ft in length.
• A lakefront lot owes a deeper rear yard, set at 120 ft under its own column in the table.
• The table sets no minimum building area and no road frontage requirement in this district.

Conservation District - Beyond the 5 acre minimum, a lot needs a building area of at least 30,000 sq ft that includes one contiguous piece of at least 15,000 sq ft. The acreage is measured as net area, so deed acreage can overstate what counts.

• Net lot area is gross area minus roads, rights-of-way and easements.
• The building area, also called the building envelope, is land unencumbered by wetlands, watercourses, water bodies, rock outcroppings over 20,000 sq ft, slopes over 20% and similar constraints.
• A constrained parcel can hold the full net acreage and still fail the building area test.
• Buildings, driveways and site amenities are intended to sit primarily within the building area.
• The 10% figure is a maximum impervious cover, the complement of a minimum open area of 90%; no building coverage percentage is published.
• A lakefront lot has its own rear yard requirement of 100 ft.

Low Density Residence - The 3 acre minimum is net land: gross lot area less roads, rights-of-way and easements. A lot must also hold 30,000 sq ft of building area, including one contiguous piece of at least 15,000 sq ft, so a constrained parcel can meet the acreage and still fail.

• Building area is land unencumbered by wetlands, watercourses, water bodies, rock outcroppings over 20,000 sq ft, slopes over 20% and similar constraints.
• The 15% figure is a maximum impervious cover, the complement of a minimum open area of 85% counting all buildings, structures, paved areas and other impervious surfaces.
• A lakefront lot owes a deeper rear yard of 75 ft.
• Multifamily is permitted here under § 165-19: at least five buildable acres, up to eight dwelling units per buildable acre, capped at 100 dwelling units per project.
• Multifamily yards are 100 ft front and 50 ft on one side, coverage is capped at 25% for all structures, and land per unit runs 4,000 sq ft for a studio to 10,000 sq ft for a three-bedroom.
• Multifamily needs 200 ft of frontage on an existing public road, two means of ingress and egress at least 100 ft apart, and 40% of the site as open space including a recreation area.

Moderate Density Residence - The 2-acre minimum is net land, gross area less roads, rights-of-way and easements, and a separate minimum building area of 30,000 sq ft of unconstrained land applies on top, which must include one contiguous piece of at least 15,000 sq ft.

• The building area excludes wetlands, watercourses, water bodies, rock outcroppings over 20,000 sq ft and slopes over 20%; buildings and driveways are intended to sit primarily within it.
• The 25% shown is a maximum impervious cover, counting buildings, structures and paved areas; it is the complement of a minimum open area of 75%.
• A lakefront lot owes a deeper rear yard of 75 ft in place of the rear setback shown.
• Multifamily is permitted in R-2 and § 165-19 gives it its own standards: at least 5 buildable acres, up to 8 dwelling units per buildable acre, capped at 100 dwelling units per project.
• For multifamily, land per dwelling unit is 4,000 sq ft for a studio, 6,000 for a one-bedroom, 8,000 for a two-bedroom and 10,000 for a three-bedroom.
• Multifamily also needs 200 ft of frontage on an existing public road, two means of ingress and egress at least 100 ft apart, and at least 40% of the site as open space.

Medium Density Residence - The one-acre minimum is net land after roads, rights-of-way and easements come out, and a lot needs 20,000 sq ft of building area with one contiguous piece of at least 15,000 sq ft. Building area excludes wetlands, watercourses, slopes over 20% and similar constraints.

• Multifamily is permitted by right under § 165-19 on standards of its own: at least five buildable acres, up to eight dwelling units per buildable acre, and no more than 100 units per project.
• Multifamily bulk runs separately: 200 ft lot width, 100 ft front, 50 ft side, 50 ft rear, 25% coverage for all structures, and two and a half stories or 35 ft, whichever is less.
• A lakefront lot owes a deeper rear yard of 75 ft.
• The 40% figure caps impervious cover, counting buildings, structures, paved areas and other impervious surfaces; the town publishes it as a minimum open area of 60%.
• A maximum building length of 100 ft applies.
• A single-family zero lot line dwelling is permitted by right in R-1.

Lake Peekskill - The two-acre minimum is a net area, gross lot area minus roads, rights-of-way and easements, so deed acreage overstates it. A separate minimum building area of 30,000 sq ft applies on top of the lot minimum.

• Building area is land unencumbered by wetlands, watercourses, water bodies, rock outcroppings over 20,000 sq ft and slopes over 20%, and must contain one contiguous area of at least 15,000 sq ft.
• The 25% figure is a maximum impervious cover, the complement of a minimum open area of 75% of gross site area; the town publishes no building coverage percentage.
• A lakefront lot owes a deeper rear yard of 75 ft in place of the rear yard shown.
• Maximum building length is 100 ft.
• Multifamily is permitted by right under § 165-19, which sets its own figures: five buildable acres minimum, up to eight units per buildable acre, 100 units per project and 200 ft of road frontage.
• A single-family zero lot line dwelling is reachable by special permit.

Neighborhood Commercial - Minimum lot size is measured as net area, gross area less roads, rights-of-way and easements, so deed acreage overstates what counts. A lakefront lot owes a deeper rear yard of 75 ft rather than the rear setback shown.

• A lakefront lot must provide a 75 ft rear yard.
• Residential use above a commercial use is permitted by right in CN.
• No minimum building area and no minimum open area are set for this district, so no open-area floor or impervious cap applies.
• No maximum building length is set for this district.

Community Commercial One - The minimum lot size is a net area, gross area less roads, rights of way and easements, so deed acreage can overstate what counts. A lakefront lot owes a 75 ft rear yard in place of the rear setback shown.

• Residential use above a commercial use is permitted by right in CC-1.
• The code states no minimum building area and no minimum open area here, so neither an open-area floor nor a coverage cap applies.
• The code states no maximum building length for this district.

Community Commercial Two - The minimum lot size is a net figure, gross area less roads, rights-of-way and easements, so deed acreage overstates what counts toward it. A lakefront lot owes a deeper rear yard of 75 ft in place of the rear setback shown.

• Lakefront parcels: the rear yard requirement is 75 ft rather than the rear setback shown.
• Residential use above a commercial use is permitted by right in CC-2.
• The table sets no minimum building area and no minimum open area here, so no open-area floor and no impervious cap apply.
• No maximum building length is set for this district.

Planned Commercial Park - The 5 acre minimum is a net area figure, gross lot area minus roads, rights-of-way and easements, so deed acreage overstates what counts toward it. The 30% figure caps all impervious cover, not just buildings.

• Open area must be at least 70% of gross site area, measured after the footprint of all buildings, structures, paved areas and other impervious surfaces.
• The town states no building coverage percentage, so the impervious cover limit is the only coverage control here.
• A lakefront lot owes a deeper rear yard, set at 100 ft in its own column of the table.
• Residential use above a commercial use is permitted by right.
• The table states no minimum building area for this district.
• The table states no maximum building length for this district.