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ADU · Sullivan County

Are ADUs allowed in Sullivan County, NY?

There is no county-wide answer. In New York an accessory dwelling unit is governed by the town, city or village — so the rule changes at every municipal line, and often between districts inside one town. Below is each of the 20 municipalities in Sullivan County, with what its zoning districts actually say.

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ADU rules by municipality in Sullivan County

Can you build an ADU in Bethel, NY?

All districts prohibit ADUs.

Bethel's use schedule lists no accessory apartment or accessory dwelling unit, so an accessory unit is not an available use in any district.

Reviewed 2026-10-07 Full Bethel ADU rules →

Can you build an ADU in Callicoon, NY?

All districts prohibit ADUs.

There is no accessory dwelling unit. A second unit comes only by converting an existing dwelling to two-family use: by right in CD, where no more than two people may occupy the second unit, by right in SD, and by Planning Board approval in RU, BD and RB.

Ch. 203 § 203-18 Residential conversions; § 203-9B legend; § 203-9D steep slopes; § 203-10B closed list; § 203-28 Accessory uses; Schedule of Use Regulations Attachments 1-3 Reviewed 2026-10-07 Full Callicoon ADU rules →

Can you build an ADU in Cochecton, NY?

All districts prohibit ADUs.

There is no accessory dwelling unit provision in Cochecton. A second unit comes instead as a two-family dwelling, which is a principal permitted use as a matter of right in RU, HD and ND, while AC confines itself to single-family dwellings.

240 Attachment 1 (Schedule of District Regulations) · § 240-8 · § 240-11 · § 240-12B · § 240-13A Reviewed 2026-10-07 Full Cochecton ADU rules →

Can you build an ADU in Delaware, NY?

All districts prohibit ADUs.

The town has no accessory dwelling unit. The practical way to add one is converting a house, which § 220-41 allows wherever a two-family is permitted: by right in DR, CAL-B-1, CAL-R-1, R-1, RU and B-1, and by special use in PUD. That makes two full dwellings.

Ch. 220 § 220-41 Conversion of dwellings; § 220-40 Two-family dwellings; § 220-30A; § 220-11; § 220-9 and 220 Attachment 1 Schedule of District Regulations Reviewed 2026-10-07 Full Delaware ADU rules →

Can you build an ADU in Fallsburg, NY?

All districts prohibit ADUs.

Fallsburg's zoning carries no accessory apartment or accessory dwelling unit use, so a second unit added to a single-family lot is not available in AG, REC, R, HR, B, MX or PRD. A second unit is only possible where a district allows one as its own principal use.

Ch. 310 Attachment 2 Schedule I Table of Use and Bulk Requirements (Supp 30, Oct 2025, through L.L. No. 4-2025); Art. II Terminology; Art. VI Special Permit Uses Reviewed 2026-10-07 Full Fallsburg ADU rules →

Can you build an ADU in Forestburgh, NY?

All districts prohibit ADUs.

Forestburgh's zoning code lists no accessory dwelling unit, accessory apartment or guest cottage use, and § 180-7(E) prohibits any use not explicitly listed as permitted or special. A two-family dwelling is permitted by right, so a second unit is reachable as a duplex.

L.L. No. 3 of 2023 (Ch. 180, adopted 11-2-2023) § 180-4 List of Districts; § 180-7(E) closed list; § 180-8 Table of Use and Bulk Requirements; § 180-25 Reviewed 2026-10-07 Full Forestburgh ADU rules →

Can you build an ADU in Fremont, NY?

ADU data not yet available - verify with the building department at (845) 887-6605.

Fremont's code has no accessory dwelling unit, accessory apartment, in-law apartment or guest cottage category, and § 100.14(E) prohibits any use not specifically listed on the Schedule of District Regulations. No district lists a second dwelling unit as an accessory use.

Zoning Law Section 100 (2016) § 100.10 districts; § 100.13 definitions; § 100.14(E) unlisted uses; § 100.15(A); Appendix 2 Schedule of District Regulations Reviewed 2026-10-07 Full Fremont ADU rules →

Can you build an ADU in Highland, NY?

All districts allow ADUs with a special-use permit.

An accessory dwelling requires a special use permit plus site plan approval in H-C, R-1 and R-2, and must be inside the primary house or an attached structure. The owner has to live in one of the two units.

Ch. 190 (amended in entirety 4-13-2021 by L.L. No. 1-2021) § 190-20 Accessory Dwellings; § 190-34 Guest Homes; § 190-12(B)-(C); § 190-18(B)-(C); § 190-21; Schedule 2 Reviewed 2026-10-07 Full Highland ADU rules →

Can you build an ADU in Liberty, NY?

All districts prohibit ADUs.

Liberty's zoning law lists no accessory apartment or accessory dwelling unit, and under § 147-8 any use not listed in the Schedule of District Regulations is prohibited. A second unit here is built as a two-family dwelling instead.

Ch. 147 § 147-8 closed list; § 147-9; Attachment 1 Schedule of District Regulations (print date 07-01-2015, amended through L.L. No. 5-2013) Reviewed 2026-10-07 Full Liberty ADU rules →

Can you build an ADU in Lumberland, NY?

All districts allow ADUs with occupancy restrictions.

An accessory apartment is permitted in every district with the same zoning and building permit as the house, without Planning Board approval. It must be accessory to an owner-occupied single-family dwelling, and the apartment itself may be rented.

Ch. 250 Art. XI Schedule of Uses and Bulk Regulations §§ 250-76 to 250-83; Art. II definition of accessory apartment; § 250-14; § 250-29H; § 250-37 care cottages Reviewed 2026-10-07 Full Lumberland ADU rules →

Can you build an ADU in Mamakating, NY?

7 districts prohibit ADUs, 2 require a special-use permit, 1 allows them.

An accessory apartment has to sit inside an existing house designed for one family, so no detached unit is allowed anywhere in the town. Under § 199-6 it is available only in districts that permit a two-family dwelling, and it must meet the two-family standards.

Ch. 199 § 199-6 definition of accessory apartment; § 199-7C and § 199-8.1 closed list; Schedule I Table of Use and Bulk Requirements (199 Attachment 2), as amended in its entirety by L.L. No. 6-2019 Reviewed 2026-10-07 Full Mamakating ADU rules →

Can you build an ADU in Neversink, NY?

All districts prohibit ADUs.

Neversink's zoning lists no accessory apartment or accessory dwelling unit, and § 50-9D deems any use not specifically permitted to be prohibited. The route to a second unit is instead a two-family dwelling, a principal permitted use in each of the town's districts.

Ch. 50 § 50-8 and § 50-9D closed list; § 50-9A; Attachment 1 Schedule of District Regulations (print 05-01-2019, amended through L.L. No. 2-2015); Art. VI §§ 50-15 to 50-19 Reviewed 2026-10-07 Full Neversink ADU rules →

Can you build an ADU in Rockland, NY?

All districts allow ADUs with occupancy restrictions.

Town-wide, the only accessory unit is a temporary mother-daughter apartment inside a single-family home, allowed wherever a single-family dwelling is permitted. It cannot be rented out: occupancy is limited to a dependent relative of the principal occupants.

Ch. 185 § 185-7 definition of dwelling, single-family; § 185-11 closed list; § 185-13A two-family lot area; Appendix 1 Schedule of District Regulations (Supp 3, Mar 2026, through L.L. No. 2-2025) Reviewed 2026-10-07 Full Rockland ADU rules →

Can you build an ADU in Thompson, NY?

5 districts prohibit ADUs, 3 allow them.

In RR-1, RR-2 and SR, a second detached single-family house is permitted with a building permit on a lot large enough to be subdivided under the district's standard minimums. Both houses must stay in common ownership.

Ch. 250 Schedules of District Regulations, Attachments 1-7 and 9, Note 1 to the SR/RR-1/RR-2 schedules; § 250-46A(3); EBG provisions added by L.L. No. 2-2020 Reviewed 2026-10-07 Full Thompson ADU rules →

Can you build an ADU in Tusten, NY?

6 districts allow ADUs, 1 does not.

An accessory dwelling is a listed accessory use in SR, RR, R1, R2, GR and RB, needing only a building permit rather than planning board approval. It is not among the accessory uses listed in DB, where any use not specifically listed is prohibited.

Ch. 300 § 300-4.0 Schedule of District Regulations (amended 9-13-2022 by L.L. No. 1-2022); § 300-4.0B; § 300-4.1D; Art. II definitions of dwelling, accessory and accessory apartment, family based Reviewed 2026-10-07 Full Tusten ADU rules →

Can you build an ADU in Bloomingburg, NY?

2 districts allow ADUs, 1 does not, 1 requires a special-use permit.

In R-1 an accessory apartment is permitted inside a single-family dwelling with site plan review approval, and the code attaches no owner-occupancy or rent restriction to it. Detached units are not provided for.

Village Zoning Law Sec. 2.1 definition of Accessory Apartment; Sec. 4.3(e) R-1 site plan review; Secs. 5.2-5.4 NBD; Secs. 6.3, 6.5, 6.12 PUDR; Secs. 7.3-7.4 PUDC; Sec. 9.15 Reviewed 2026-10-07 Full Bloomingburg ADU rules →

Can you build an ADU in Jeffersonville, NY?

All districts prohibit ADUs.

No accessory structure may be used as a dwelling anywhere in the village (§ 80-18F), so a detached cottage or converted garage apartment is off the table. A second unit has to come as a two-family dwelling, a principal permitted use in DD and a special use in RS.

Zoning and Subdivision Law (L.L. No. 2 of 1998, as amended by L.L. No. 1 of 2012) § 80-18F; § 80-14A; § 80-15O; § 80-08 definitions; Schedule of District Regulations Reviewed 2026-10-07 Full Jeffersonville ADU rules →

Can you build an ADU in Liberty, NY?

All districts prohibit ADUs.

There is no accessory apartment use, and nothing provides for a detached accessory dwelling. Carving a second unit out of an existing house is a residential conversion needing a special use permit in R-1, R-2 and C, which makes two full dwellings rather than an accessory unit.

Ch. 87 (adopted 6-11-2008 by L.L. No. 4-2008) § 87-30 Conversions of Residential Structures; § 87-9.B unlisted uses; § 87-10.A lot standards; § 87-13; Schedule of District Regulations Reviewed 2026-10-07 Full Liberty ADU rules →

Can you build an ADU in Monticello, NY?

All districts prohibit ADUs.

No district's use list includes an accessory apartment, in-law apartment or guest cottage. A second unit is possible as a two-family dwelling, which is permitted by right in R-2, R-M and B-1 but not in R-1.

Ch. 280 Attachments 1, 2, 3, 5 and 7 — R-1, R-2, R-M, B-1 and B-2 Schedules of Use, Area and Bulk Regulations (Attachments 3 and 5 amended 9-4-2019 by L.L. No. 6-2019) Reviewed 2026-10-07 Full Monticello ADU rules →

Can you build an ADU in Woodridge, NY?

All districts prohibit ADUs.

Woodridge's code has no accessory dwelling unit use, so a separate accessory apartment is not available in any district. The route to a second unit is a two-family dwelling, a principal use permitted by right in R-2 and VC only.

Reviewed 2026-10-07 Full Woodridge ADU rules →

Sullivan County municipalities with no published zoning code

These 1 municipality have no zoning code we can read online, which means an ADU question has to be answered by the municipality itself.

ADU questions people ask about Sullivan County

Are ADUs allowed in Sullivan County?

There is no single county-wide answer — ADUs are governed by each town, city and village, not by the county. Of the 20 Sullivan County municipalities with mapped zoning districts, 7 allow an accessory dwelling unit in at least one district, and 4 allow one by right somewhere. The section for your municipality below gives the specific answer.

Does Sullivan County issue ADU permits?

No. Zoning approval and building permits both come from the municipality — the town, city or village — not the county. County health departments do commonly review septic and water supply for a new dwelling unit, which is often the binding constraint on a rural lot.

What size ADU can I build in Sullivan County?

Size caps are set per municipality and frequently per district, and they are one of the details most often stated wrongly by national ADU sites. Open your municipality's page below for the code sections analyzed, then confirm the current figure with the building department before you design to it.

What an ADU costs to build in Sullivan County

Permission and budget are separate questions. See the Sullivan County cost-to-build breakdown for current per-square-foot ranges — an accessory unit runs above a full house per square foot, because the kitchen, bath, panel and heating plant cost the same at any size.

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More on Sullivan County: Zoning for new construction by town · Cost to build · ADU rules across every county we cover

ADU information for Sullivan County is compiled from each municipality's own code , most recently reviewed 2026-10-07, and provided for decision-support only — not legal or architectural advice. Eligibility, size, owner-occupancy and permit conditions vary by district and often carry exceptions; confirm with the municipality before relying on any answer. 1 of the 20 municipalities below still have one or more districts that have not been analyzed, and each says so in its own section. Source: the Offsite / Aldo zoning dataset.

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