ADU · Albany County
Can you build an ADU in Knox, NY?
Town of Knox has 9 districts. 8 of 9 districts prohibit ADUs. 1 district has incomplete data - verify with the building department at (518) 872-2551. Check your address to confirm the district that applies to your parcel:
What the Knox code says
Knox has no accessory apartment use in any district. A second household means a two-family house, permitted by right in R-K, AG, B1, AM and MRD with no occupancy or size condition. LC-1 and LC-2 permit no dwelling.
Conditions the code attaches:
- A two-family dwelling is simply a building with two dwelling units, with no rule on who lives in either.
- A multiple dwelling of two stories or less and three units or less needs a special use permit from the Zoning Board of Appeals in those same districts.
- The building department can be reached at (518) 872-2551.
What the Knox 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 |
|---|---|---|---|---|
| Agricultural | 3 ac | 75 / 50 / 50 ft | 35 ft | No |
| Ag & Mining | 3 ac | 75 / 50 / 50 ft | 35 ft | No |
| Multi-Use & B1 | 3 ac | 75 / - / 30 ft | 35 ft | No |
| Multi_Use and Agricultural | — | — | — | No |
| Land Conservation 1 | 3 ac | 75 / 50 / 50 ft | 35 ft | No |
| Land Conservation 2 | 3 ac | 75 / 50 / 50 ft | 35 ft | No |
| Residential | 3 ac | 75 / 50 / 50 ft | 35 ft | No |
| Residential/Recreational | — | — | — | — |
| Multi-Use Recreational | 3 ac | 75 / - / - ft | 35 ft | No |
Agricultural, Ag & Mining - The three acre minimum is per family, not per lot, so a two-family dwelling needs six acres and the figure scales with the unit count. The 25% coverage cap includes accessory buildings.
- A nonresidential use needs ten acres and 400 ft of frontage, and a recreational facility 50 acres.
- Where a side or rear yard adjoins a street, the front yard standard applies to it under § 52C.
- Yards are measured from the foundation under § 52G.
- Cluster development under § 50O and multiple dwellings under § 50K change the lot requirement.
Multi-Use & B1 - No side yard is required here except where the lot abuts property in residential use. A side yard that is then provided must be at least 12.5 ft, and where the lot abuts a residential district at least 100 ft.
- The three acre minimum is per family, not per lot, so a two-family dwelling needs six acres.
- A nonresidential use needs the same three acres, on 200 ft of frontage rather than 250 ft.
- This district reaches three storeys, and no minimum living space is published.
- Where a side or rear yard adjoins a street, the front yard standard applies to it under § 52C.
- Yards are measured from the foundation under § 52G.
- Cluster development under § 50O and multiple dwellings under § 50K change the lot requirement.
Multi_Use and Agricultural - No district of this name appears in the zoning ordinance, so it carries no dimensional standard of its own. The label reads as two district names run together, the way a parcel with split zoning is shown, so resolve the parcel to its actual district on the Town Zoning Map.
Land Conservation 1, Land Conservation 2 - The Density Control Schedule leaves this district's row entirely blank. The figures shown match the row printed directly above it, so they may carry down or the town may publish no dimensional standard here: confirm them with the town before relying on them.
- Where a side or rear yard adjoins a street, the front yard standard applies to it (§ 52C).
- Yards are measured from the foundation (§ 52G).
Residential - The three acre minimum is per family, not per lot, so a two-family dwelling needs six acres and the figure scales with the unit count. The 25% coverage cap includes accessory buildings.
- A nonresidential use needs fifteen acres and 400 ft of frontage, five times what a dwelling needs, and a recreational facility needs 50 acres.
- Where a side or rear yard adjoins a street, the front yard standard applies to it under § 52C.
- Yards are measured from the foundation under § 52G.
- Cluster development under § 50O and multiple dwellings under § 50K change the lot requirement.
Residential/Recreational - The ordinance sets no dimensional standard for this district at all: it has no row in the Density Control Schedule. § 30(6) establishes it for seasonal dwellings on smaller lots than the town's other residential areas, but never says how much smaller, so confirm with the town.
Multi-Use Recreational - This district publishes neither a side nor a rear yard standard. The three acre minimum is also per family, not per lot, so a two-family dwelling needs six acres.
- A nonresidential use needs the same three acres, on 200 ft of frontage rather than 250 ft.
- The 30% coverage cap includes accessory buildings.
- Yards are measured from the foundation under § 52G.
- Cluster development under § 50O and multiple dwellings under § 50K change the lot requirement.
ADUs vs. short-term rentals in Knox
No local short-term-rental law on record - which is not the same as permission for Town of Knox. The Town of Knox has no local short-term rental law, and that is not permission. Confirm with the town before counting on renting a house short term. 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 minimum3 ac — an ADU still has to fit the district's lot and setback envelope.
- UtilityNational Grid territory.
- Zoning codewww.knoxny.gov/buildingzoning-department.html
- Building dept(518) 872-2551
ADU FAQ — Knox, NY
Are ADUs allowed in Knox, NY?
Town of Knox has 9 districts. 8 of 9 districts prohibit ADUs. 1 district has incomplete data - verify with the building department at (518) 872-2551. Check your address with the free ADU checker.
Do I need a special permit for an ADU in Knox?
8 of 9 districts prohibit ADUs, so no permit applies in those. 1 district has incomplete data - verify with the building department at (518) 872-2551.
Can I use an ADU as a short-term rental in Knox?
No local short-term-rental law on record - which is not the same as permission for Town of Knox. 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.
What an ADU costs to build in Knox
Permission is one question and budget is another. An 800 sq ft accessory unit here runs roughly $195k–260k 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 Knox, priced by size.
How we know this
- Sections analyzed
- Zoning Ordinance (through Amendment #14) Art IV § 40 Permitted Uses and key, § 41 Residential Uses, § 43 Accessory Uses; Art II § 20; Art III § 30, § 31
- Districts confirmed
- 8 of 9 — 1 not yet analyzed, so this page does not answer for it.
- Last reviewed
- 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 Knox: Full zoning for new construction · ADU build cost · House build cost · ADU rules across Albany County · All Albany County towns
ADU information for Town of Knox is compiled from the municipal code (last reviewed 2026-09-19) 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) 872-2551 before relying on any answer. Source: the Offsite / Aldo zoning dataset.