ADU · Rockland County
Are ADUs allowed in Rockland 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 21 municipalities in Rockland County, with what its zoning districts actually say.
- 21municipalities with mapped districts
- 6allow an ADU in at least one district
- 1allow one by right somewhere
ADU rules by municipality in Rockland County
Can you build an ADU in Clarkstown, NY?
All districts prohibit ADUs.
No accessory apartment in any district. A two-family house is permitted by right in R-10 and in MF-1, MF-2 and MF-3, which also permit apartment buildings.
Can you build an ADU in Haverstraw, NY?
6 districts prohibit ADUs, 6 allow them with occupancy restrictions.
In R-120, R-40, R-25, R-15, RG and RMH, a lot of at least 2 acres may have one guesthouse, caretaker's cottage or servant's quarters by right, 50 feet from any lot line. An accessory unit is not permitted in CR, PO, C or PIO.
Can you build an ADU in Orangetown, NY?
24 districts prohibit ADUs, 5 allow them with occupancy restrictions.
In R-80, R-40, R-22, R-15 and RG an owner who has lived in a detached one-family house for 15 years can convert it to add one apartment of up to 600 sq ft, by right. The unit ends when the owner or spouse stops living there. Business districts allow no unit an owner can add.
Can you build an ADU in Ramapo, NY?
20 districts prohibit ADUs, 2 allow them, 2 require a special-use permit.
An accessory apartment inside the house is allowed by right in R-15A and R-15C, and the owner need not live on site. It is not permitted in RR-50, R-40, R-40A, R-35, R-25, R-15, R-15MR, MR-16, NS, CS, PO, LO, PI, MR-12, MR-8, RSH, MU-1, MU-2, MU-3 or CC.
Can you build an ADU in Stony Point, NY?
9 districts prohibit ADUs, 3 require a special-use permit.
In SR-R, RR and R-1, a separate dwelling for a caretaker or servant may be permitted as an accessory use to an existing single-family home by Town Board special permit. It can only be occupied by full-time employees of the household, and the owner must live in the main house.
Can you build an ADU in Airmont, NY?
All districts prohibit ADUs.
An accessory dwelling unit is not permitted in RR-50, R-40, R-35, R-25, R-15, NS, VC, PO, LO or PI. Each residential district allows one-family detached residences with not more than one principal residential building on a lot.
Can you build an ADU in Chestnut Ridge, NY?
All districts prohibit ADUs.
An accessory apartment is not permitted in RR-50, R-40, R-35, R-25, R-20, R-15, R-15 IF, R-10, NS, PO, PO-R, LO or RS: no district lets the owner of a house lot add a second unit.
Can you build an ADU in Grand View-on-Hudson, NY?
All districts prohibit ADUs.
The Grand View-on-Hudson Zoning Law has no accessory apartment or accessory dwelling use, and Chapter VI-C bars using, altering, enlarging or building any structure for occupancy by more than one family, in both R-22 and R-10.
Can you build an ADU in Haverstraw, NY?
7 districts allow ADUs with a special-use permit, 6 do not.
An accessory apartment needs a special permit in R-1, R-1T, RC-1, RC-2, R-2 and R-3 and may house only the owner's parent, grandparent, son or daughter. In RC-1, RC-2 and R-2 an owner-occupied pre-1972 house can become a two-family let to anyone. Other districts allow neither.
Can you build an ADU in Hillburn, NY?
All districts prohibit ADUs.
Hillburn's zoning makes no provision for an accessory dwelling unit in any district. Under § 250-15C, accessory uses and structures must be clearly incidental and subordinate to the principal use of the lot, and cannot be established before a principal use or building.
Can you build an ADU in Montebello, NY?
All districts prohibit ADUs.
An accessory apartment is not permitted in ER-80, RR-50, R-35, R-25, R-15, NS, LO, LO-C, OSR, R-AH, RSH, R59-DD, EP, PI or PI-C. § 195-10 prohibits any use not identified in the use table.
Can you build an ADU in New Hempstead, NY?
All districts prohibit ADUs.
An accessory apartment is not permitted in 1R-50, 1R-40, 1R-35, 1R-25, 2R-15, LO or NCD: no district lets the owner of a house lot add a second unit. A two-family detached dwelling is a permitted principal use in 2R-15 only.
Can you build an ADU in Nyack, NY?
All districts prohibit ADUs.
The village has no accessory apartment use. Its only second-unit route is converting a single-family house to a two-family, by right in TFR and by special permit in MFR-1, MFR-2, MFR-3, RMU and OMU, which creates two full dwellings.
Can you build an ADU in Piermont, NY?
All districts prohibit ADUs.
No accessory apartment. An owner who has lived in the house for 20 years can apply to convert it to a two-family by Planning Board special permit, which changes the use of the house. It ends when the owner moves out or the house changes hands.
Can you build an ADU in Pomona, NY?
The only district prohibits ADUs.
An accessory apartment, accessory dwelling unit, in-law apartment or guest house is not permitted in R-40, Pomona's one district, so no house lot can add a second unit.
Can you build an ADU in Sloatsburg, NY?
9 of 10 districts prohibit ADUs. 1 district has incomplete data - verify with the building department at (845) 753-2727.
Sloatsburg's zoning has no accessory dwelling unit provision, and an accessory apartment is not permitted in R-80, R-40, R-15, R-10, MU-1, MU-2, VC-1, VC-3 or O. In LIO the rule is not confirmed.
Can you build an ADU in Spring Valley, NY?
All districts prohibit ADUs.
The Village of Spring Valley zoning code has no accessory dwelling unit or accessory apartment use in any district: R-1, R-1A, R-2, R-3, R-4, R-5, RSH, PRD, POR, PO, NB, GB, HB or PLI.
Can you build an ADU in Suffern, NY?
All districts prohibit ADUs.
Suffern does not allow an accessory apartment, accessory dwelling unit, in-law apartment, guest house, or servants' or caretaker's quarters in any district. Under § 266-22B, any use not specifically listed as permitted in a district is prohibited.
Can you build an ADU in Upper Nyack, NY?
7 districts allow ADUs with a special-use permit, 4 do not.
An owner-occupied accessory apartment is a special use permit use in every residential district (§ 9.6.11), and the owner must live in one of the two units for the life of the permit. One is allowed per lot, only accessory to a one-family dwelling.
Can you build an ADU in Wesley Hills, NY?
All districts prohibit ADUs.
The Village of Wesley Hills has no accessory dwelling provision under any name, and § 230-16B deems any use not specifically listed as permitted to be prohibited. That holds in R-50, R-35, R-20, R-15 and NS alike.
Can you build an ADU in West Haverstraw, NY?
8 of 9 districts prohibit ADUs. 1 district has incomplete data - verify with the building department at (845) 947-2800.
No accessory dwelling unit is allowed in R-1, R-2, R-3, R-4, C, PLI, MLI or OSC, where the accessory uses are a closed list with no dwelling in it and the code bars building or converting space for any use it does not list. In L-1 the rule is not confirmed.
Rockland County municipalities with no published zoning code
These 2 municipalities have no zoning code we can read online, which means an ADU question has to be answered by the municipality itself.
- Village of Kaser — (845) 352-2932
- Village of New Square — (845) 558-5904
ADU questions people ask about Rockland County
Are ADUs allowed in Rockland County?
There is no single county-wide answer — ADUs are governed by each town, city and village, not by the county. Of the 21 Rockland County municipalities with mapped zoning districts, 6 allow an accessory dwelling unit in at least one district, and 1 allow one by right somewhere. The section for your municipality below gives the specific answer.
Does Rockland 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 Rockland 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 Rockland County
Permission and budget are separate questions. See the Rockland 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.
More on Rockland County: Zoning for new construction by town · Cost to build · ADU rules across every county we cover
ADU information for Rockland County is compiled from each municipality's own code , most recently reviewed 2026-08-16, 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. 2 of the 21 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.