ADU · Greene County

Can you build an ADU in Athens, NY?

Town of Athens has 13 districts. 7 districts allow ADUs, 2 do not, 1 requires a special-use permit. 3 districts have incomplete data - verify with the building department at (518) 945-1052. Check your address to confirm the district that applies to your parcel:

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What the Athens code says

An accessory apartment inside the principal building is permitted with no Planning Board or ZBA review in Rr, Ru, Ru-1, Ag, OS, H and Ru-385, on a lot meeting the district minimum. It may be no more than half the size of the house. A detached unit needs a special use permit.

Conditions the code attaches:

The unit may be no larger than 50% of the principal building’s square footage, not counting an unfinished basement (§ 180-43C).
No owner-occupancy, family or age condition applies: § 180-43D only requires the owner to keep the building and grounds in good condition.
A detached unit needs a Planning Board special use permit, and the lot must meet the district minimum twice over, once for the house and once for the structure (§ 180-43B).
A detached unit counts as a dwelling unit for density under § 180-12, so it consumes the district’s per-dwelling acreage.
One accessory apartment per dwelling or lot (§ 180-43E), and two off-street parking spaces on top of those for the house (§ 180-43G).
The entry and design may not change the building’s appearance as a single-family structure (§ 180-43F).
In MUC the unit needs site plan approval and a special use permit whether attached or detached; it is not listed for LI-1 or LI-2.
A watershed overlay takes its answer from the district beneath it; see each overlay’s own note.

How big an ADU can be in Athens

Size limits are set per district, and a unit inside the house is a different standard from a detached one. These are the figures the code publishes.

Inside the principal dwelling

50% of the principal dwelling, and smaller than the principal dwelling

Rr, Ru, Ru-1, H, MUC, Ag, OS, Ru-385 · § 180-43A, C

Detached

50% of the principal dwelling, and smaller than the principal dwelling

Rr, Ru, Ru-1, H, MUC, Ag, OS, Ru-385 · § 180-43B, C

What the Athens code indicates by district

The table below shows how each district treats ADUs, alongside the lot and setback standards that govern a second unit. District boundaries and conditions vary, so treat this as a starting point and confirm the district that applies to your parcel.

District	Min lot	Setbacks F / S / R	Max height	ADU
Rural Residential District	1.49 ac	25 / 40 / 25 ft	35 ft	As of right
Rural District	3 ac	50 / 30 / 50 ft	35 ft	As of right
Rural District (Moderate Density)	1 ac	25 / 30 / 50 ft	35 ft	As of right
Hamlet District	0.72 ac	25 / 20 / 25 ft	25 ft	As of right
Mixed Use Commercial District	2.98 ac	40 / 25 / 50 ft	35 ft	Special permit
Light Industrial District 1	2 ac	100 / 50 / 50 ft	45 ft	No
Light Industrial District 2	2 ac	100 / 50 / 50 ft	45 ft	No
Agriculture District	10 ac	75 / 50 / 50 ft	35 ft	As of right
Open Space District	5 ac	75 / 50 / 50 ft	35 ft	As of right
Rural Residential / Route 385 Corridor	3 ac	75 / 50 / 50 ft	35 ft	As of right
Hollister Lake Watershed Overlay	5 ac	75 / 50 / 50 ft	35 ft	—
Green Lake Watershed Overlay	5 ac	75 / 50 / 50 ft	35 ft	—
Black Lake Watershed Overlay	5 ac	75 / 50 / 50 ft	35 ft	—

Rural Residential District - The figures shown apply to lots on on-lot water and septic. With public water and sewer the minimum lot drops to 15,100 square feet (0.3467 acre) on 100 ft of width, with a 15 ft side yard.

With either public water or public sewer alone, the minimum lot is 30,000 square feet (0.6887 acre) on 125 ft of width, and the 40 ft side yard does not change.
The lot area shown is the land required per dwelling unit, and it is the minimum lot size unless the Planning Board allows an average lot size under § 180-12C.
A nonresidential use is sized on its own column: 20,000 square feet (0.4591 acre) with public water or public sewer, and 1 acre on on-lot water and septic.
The 25 ft front and rear yards and the 100 ft lot depth stay the same whichever services the lot has.
The coverage cap is a maximum percent of parcel coverage and applies to all lots.

Rural District - Each dwelling unit requires 3 acres, and public water or sewer does not lower that. The 3 acres is also the minimum lot size unless the Planning Board allows an average lot size under § 180-12C.

The figures shown apply to lots served by on-lot water and sewage disposal.
A nonresidential use is sized separately: 20,000 square feet with public water or public sewer, or 1 acre with on-lot water and sewage disposal.
Yards, lot width, lot depth, height and coverage for a nonresidential use are the same as for a dwelling.
The 30% coverage figure is a maximum percent parcel coverage and applies to all lots.

Rural District (Moderate Density) - The 1 acre is a density standard, one dwelling unit per acre, and it also serves as the minimum lot size unless the Planning Board allows an average lot size under § 180-12C. The acre applies whether or not public water or sewer reaches the lot.

A nonresidential use needs the same 1 acre of lot area.
The 30% coverage figure is a maximum parcel coverage and applies to all lots.

Hamlet District - The lot minimum shown applies where water and sewage are handled on the lot. With public water and sewer the hamlet lot minimum is 10,000 square feet (0.2296 acre); with either public water or public sewer alone, 20,000 square feet (0.4591 acre).

This district also sets a maximum front yard of 35 ft: a building must come within 35 ft of the front lot line as well as keeping the 25 ft front setback.
A nonresidential use is sized separately: 20,000 square feet (0.4591 acre) with public water or public sewer, and 1 acre on on-lot water and sewage disposal.
The lot figure is a residential density, the land each dwelling unit requires, and it is the minimum lot size unless the Planning Board allows an average lot size under § 180-12C.
The 80 ft width and depth, the yards, the 25 ft height and the 40% coverage are the same whichever water and sewer service a lot has.
The coverage figure is a maximum percent parcel coverage and applies to all lots.

Mixed Use Commercial District - The lot size shown applies to a dwelling; a nonresidential use needs 1 acre. Each dwelling unit requires 130,000 square feet, and that density sets the minimum lot size unless the Planning Board allows an average lot size under § 180-12C.

For a nonresidential use the yards, lot width, lot depth, height and coverage are the same as for a dwelling.
The coverage figure is a maximum percent parcel coverage and applies to all lots.
These standards are set for on-lot water and sewage disposal.
Residential use is allowed in this district as per Table 2, but it is not encouraged.

Agriculture District - A dwelling here requires one dwelling unit per 10 acres, and that density also sets the minimum lot size unless the Planning Board approves an average lot size under § 180-12C.

A nonresidential use is sized separately, at 1 acre of lot area; the yards, width, depth, height and coverage stay the same as for a dwelling.
These figures apply to lots with on-lot water and sewage disposal.
The 25% coverage cap is a maximum parcel coverage and applies to all lots.

Open Space District - The 5 acre figure is a density of one dwelling unit per 5 acres, set as the minimum lot size for a dwelling. A nonresidential use is sized on its own standard at 1 acre, with the same yards, width, depth, height and coverage.

The Planning Board may allow an average lot size in place of the 5 acre minimum under § 180-12C.
These figures apply to lots served by on-lot water and sewage disposal.
The coverage cap is a maximum percent of parcel coverage and applies to all lots.

Rural Residential / Route 385 Corridor - One dwelling unit per 3 acres, the same whether the lot has public water and sewer, one of the two, or on-lot water and sewage disposal. That 3 acres is also the minimum lot size unless the Planning Board allows an average lot size under § 180-12C.

A nonresidential use is sized by its own standard: 20,000 square feet where there is public water or public sewer, or 1 acre on on-lot water and sewage disposal.
Yards, lot width, lot depth, height and coverage are the same for a nonresidential use as for a dwelling.
The coverage cap is a maximum percent of parcel coverage and applies to all lots.
The dimensions shown are the case for lots on on-lot water and sewage disposal.

Hollister Lake Watershed Overlay - This overlay sits over an underlying district, and that district answers what uses are allowed on the parcel. Land must provide 5 acres per dwelling unit, and the 15% coverage cap is measured across the whole parcel and applies to all lots.

A nonresidential use is sized on its own 2 acre lot minimum; the yards, width, depth, height and coverage stay the same as for a dwelling.
The minimum lot size may differ where the Planning Board allows an average lot size under § 180-12C.
Under § 180-30, site disturbance must stay 100 ft back from DEC streams classed C(T) and higher and 50 ft from nonregulated watercourses.
Any alteration of a watercourse requires Planning Board review.
§ 180-15A bars on-site waste disposal, spreading of septage or sludge, dumping of imported road salt or sand, and bulk storage of fuels, chemicals and fertilisers except in sealed structures.
These figures assume on-lot water and sewage disposal.

Green Lake Watershed Overlay - This is a watershed overlay: the figures set density at one dwelling unit per 5 acres, but what may be built comes from the district beneath it. Site disturbance must stay 100 ft back from DEC streams classed C(T) and higher and 50 ft from nonregulated watercourses.

A nonresidential use is sized by its own standard, 2 acres; the yards, width, depth, height and coverage match those for a dwelling.
The 5 acre figure is the minimum lot size unless the Planning Board allows an average lot size under § 180-12C.
The 15% figure is a maximum parcel coverage and applies to all lots.
§ 180-15A prohibits on-site disposal of waste and the surface application of septage or sludge.
§ 180-15A also prohibits disposal of imported road salt or sand and bulk storage of fuels, chemicals and fertilisers except in sealed structures.
Any alteration of a watercourse requires Planning Board review under § 180-30.

Black Lake Watershed Overlay - Site disturbance has to stay 100 ft back from DEC streams classed C(T) and higher and 50 ft from nonregulated watercourses, on top of the yards shown. The figures shown are this overlay's own row.

A nonresidential use is sized by its own standard, a minimum lot size of 2 acres; the yards, width, depth, height and coverage are the same as for a dwelling.
Which uses are allowed, including whether an accessory apartment is available, is answered by the district beneath this overlay.
The 5 acres is the land each dwelling unit requires, and it is also the minimum lot size unless the Planning Board allows an average lot size under § 180-12C.
§ 180-15A prohibits on-site disposal of waste, surface application of septage or sludge, and disposal of imported road salt or sand.
Bulk storage of fuels, chemicals and fertilisers is prohibited except in sealed structures under § 180-15A.
Any alteration of a watercourse requires Planning Board review under § 180-30.

ADUs vs. short-term rentals in Athens

Short-term rentals allowed with local rules for Town of Athens. Short-term rentals here are governed by the town's short-term residential rental law, Chapter 147. Renting requires annual registration with the Town Clerk and a code compliance inspection. These are separate questions from whether you can build an ADU — a unit you're allowed to add isn't automatically one you're allowed to rent nightly, so check both.

Good to know

Residential lot minimum0.72–10 ac — an ADU still has to fit the district's lot and setback envelope.
UtilityCentral Hudson territory.
Zoning codeecode360.com/12635545
Building dept(518) 945-1052

ADU FAQ — Athens, NY

Are ADUs allowed in Athens, NY?

Do I need a special permit for an ADU in Athens?

It depends on the district: 1 of 13 require a special-use permit, the rest do not. Check the district that applies to your parcel before you design.

Can I use an ADU as a short-term rental in Athens?

Short-term rentals allowed with local rules for Town of Athens. ADU occupancy and short-term-rental rules are separate: an ADU you can build isn't automatically one you can rent nightly. Confirm both before you count on STR income.

Run the free ADU check for your parcel →

What an ADU costs to build in Athens

Permission is one question and budget is another. An 800 sq ft accessory unit here runs roughly $195k–255k at a standard finish, and the per-square-foot rate comes in above a full house because the kitchen, bath, panel and heating plant cost the same either way. See the full cost to build an ADU in Athens, priced by size.

How we know this

Sections analyzed: Ch. 180 Attachment 1 Table 1 Schedule of Uses, both accessory apartment rows (in principal building; not in principal building); § 180-43 Accessory apartments A through H; § 180-4 district list; § 180-15A Watershed Overlay prohibitions; Attachment 2 Table 2
Districts confirmed: 10 of 13 — 3 not yet analyzed, so this page does not answer for them.
Last reviewed: 2026-10-01
Not covered here: Overlay districts, the zoning map, and any conditions attached to an individual parcel. Size limits and owner-occupancy terms sit in the code section above, not in this summary.

More on Athens: Full zoning for new construction · ADU build cost · House build cost · ADU rules across Greene County · All Greene County towns

ADU information for Town of Athens is compiled from the municipal code (last reviewed 2026-10-01) and provided for decision-support only — not legal or architectural advice. ADU eligibility, size, owner-occupancy and permit conditions vary by district and often carry exceptions; verify with the building department at (518) 945-1052 before relying on any answer. Source: the Offsite / Aldo zoning dataset.