Can you build an ADU in Northumberland, NY?

APD Agricultural Protection - The 10% coverage cap counts the house and all accessory structures together. A farm, agricultural pursuit, agricultural use structure or forestry use needs at least 10 acres on 300 ft of frontage, twice the land of a house.

• The 300 ft figure is frontage along the road, not width at the building line, where the ordinance sets no figure.
• For farms and agricultural use structures, a silo is exempt from the 35 ft height limit and capped at 90 ft instead.
• Mining needs only 1 acre but 100 ft on all three yards, and agribusinesses, sawmills and riding stables also take 100 ft yards.
• By special permit, a bed-and-breakfast, garden shop, nursing home, marina or park needs 5 acres. A nursing home also needs a 100 ft front yard and 50 ft side and rear yards.
• A home occupation needs 5 acres and a farm employee dwelling unit 10 acres.
• Fences and walls are capped at 6 ft high and a satellite dish at 15 ft.

R-3 Residential - A two-family dwelling has no route in R-3. The residential uses are a single-family dwelling and, as an accessory use, a farm employee dwelling unit.

• The 20% coverage cap counts the house and all accessory structures together.
• A farm needs 5 acres on 300 ft of frontage, and agricultural pursuits, agricultural use structures and forestry uses 10 acres on 300 ft.
• By special permit, a stable or riding academy needs at least 10 acres and a veterinarian clinic or hospital at least 3 acres, each with 100 ft on all three yards.
• A home occupation is a special use too, and it needs a 50 ft rear yard rather than 25 ft.
• A silo is exempt from the height limit up to 90 ft.
• The 200 ft figure is frontage along the road, not width at the building line, where the ordinance sets no figure.

R-1 Residential - A duplex is a permitted principal use on the same acre, frontage and yards as a house, with ten more percentage points of coverage. It is also listed as a special permit use, so confirm with the Building Department whether a permit is needed.

• A duplex takes the same acre, frontage and yards with coverage rising from 20% to 30%.
• The 20% coverage cap counts the house and all accessory structures together.
• R-1 is purely residential, with no commercial, farm or agricultural use.
• A park or library, by special permit, needs one acre on 200 ft of frontage. A park takes 10 ft on all three yards and 20% coverage.
• The 150 ft figure is frontage along the road, not width at the building line, where the ordinance sets no figure.
• Fences and walls are capped at 6 ft high and a satellite dish at 15 ft.

MH Mobile Home - The figures shown are for a mobile home on an established lot in an established mobile home park, not for placing one on a new lot or creating a park. Creating or expanding a park needs a special permit and 5 acres.

• Creating or expanding the park itself needs 5 acres on 150 ft of frontage, with 50 ft front and 25 ft side and rear yards and only 10% coverage, a third of the individual lot's allowance.
• The 30% coverage cap counts the home and all accessory structures together.
• A private garage or storage shed needs only 5 ft side and rear yards, and a swimming pool or satellite dish 10 ft.
• By special permit, a laundromat or a quickstop retail food store needs 20,000 sq ft on 50 ft of frontage at 50% coverage, and the food store may not have gasoline pumps.
• Also by special permit, a park or recreation area needs at least one acre on 50 ft of frontage at 10% coverage.
• The 75 ft figure is frontage along the road, not width at the building line, where the ordinance sets no figure.

C/R Commercial/Residential - A single-family dwelling is the only permitted principal use. A duplex and every commercial use need a special permit, all on the same one acre and 150 ft of frontage, with coverage varying by use.

• Coverage is 30% for a duplex or library, and 50% for offices, a research and development centre, indoor commercial recreation, a restaurant, tavern, theatre or church.
• A church may be 70 ft tall and needs 30 ft side and rear yards rather than 25 ft.
• A park is held to 10% coverage and 10 ft on all three yards.
• Coverage counts the principal building and all accessory structures together.
• The 150 ft figure is frontage along the road, not width at the building line, where the ordinance sets no figure.
• Fences and walls are capped at 6 ft high and a satellite dish at 15 ft.

H Hamlet - A duplex is a permitted principal use here, but it needs 40,000 sq ft, double the 20,000 sq ft for a single-family dwelling, on the same frontage, the same yards and the same 50% coverage.

• The 50% coverage cap counts the house and all accessory structures together.
• Commercial uses, from retail and a restaurant to a professional office or pharmacy, take the same 20,000 sq ft but only 50 ft of frontage, and most rise to 60% coverage.
• An acre is needed for a public or semi-public use or library at 75 ft of frontage, a funeral home or bed-and-breakfast at 100, and a day-care centre, nursing home, school or church at 150.
• A hotel or motel needs two acres on 100 ft of frontage.
• A church may be 70 feet tall and a personal service establishment 40 feet, against the 35 ft that applies to every other use.
• The 100 ft figure is frontage along the road, not width at the building line, where the ordinance sets no figure.

I Industrial - Nothing may be built here without a special permit, because every use in the district is a special permit use. Adult businesses and commercial communications radio towers need only one acre but 50 ft side and rear yards and 25% coverage.

• Sawmills, a lumberyard, a truck terminal and mining need 3 acres, a recyclables handling and recovery facility 2 acres, and a composting facility 5 acres.
• The figures shown cover manufacturing, research and development centres, wholesale storage and trade, agribusiness, public utility use and warehousing.
• Coverage counts the principal building and all accessory structures together.
• The 200 ft figure is frontage along the road, not width at the building line, where the ordinance sets no figure.