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Greece, NY Accessory Structures: ADU Rules (2026)

Some Restrictions
Compiled from the official code textEditor Martyn O'NeillLast verified September 2026

ADU rules in Greece, NY, also called accessory dwelling unit regulations or granny flat ordinances, cover setbacks, owner-occupancy, parking, and permit requirements.

Key Facts

Units allowed
One in-law apartment per one-family home
Size cap
30% of home's floor area or 600 sq ft
Occupant requirement
Must be an in-law, notarized affidavit required
Construction requirement
Building permit required for any remodeling
Vacancy rule
Main family regains use, no re-permitting
Rental restriction
Renting to non-in-laws expressly prohibited

Summary

Greece allows one in-law apartment per one-family home as a permitted accessory use, capped at 30% of the house's gross floor area or 600 square feet, whichever is less. The resident owner must file a notarized affidavit confirming the occupant is a relative by marriage, and any construction needs a building permit.

(12) One in-law apartment, provided that: (a) The owner of the one-family dwelling in which an in-law apartment is located shall sign a notarized affidavit or affirmation that states that the resident occupant of such apartment is an in-law of the resident family that occupies such dwelling. (b) The floor area of an in-law apartment shall not exceed 30% of the gross floor area, exclusive of attached garages, of the one-family dwelling in which such apartment is located or 600 square feet, whichever is less. (c) No construction or remodeling of a one-family dwelling in order to provide in-law apartment use shall be permitted without the issuance of a building permit. ... (f) The occupancy or rental of an in-law apartment by persons other than in-laws, as defined in this chapter, is expressly prohibited.

View official code

Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: rev 4702072; v22 updated 2025-08-21; through 08-21-2025).

Full Breakdown

Section 211-11B(12) of Greece's Zoning Code permits one in-law apartment per one-family dwelling in the R1-44, R1-18, R1-10 and R1-E Single-Family Residential Districts, subject to several conditions. ' The apartment's floor area can't exceed 30% of the gross floor area of the one-family dwelling, excluding attached garages, or 600 square feet, whichever is less. Any construction or remodeling to create the apartment requires a building permit, and the apartment may have its own exterior door as long as it connects internally to the main dwelling; it may also get its own driveway or garage bays, provided those additions get the applicable permits.

If the apartment sits vacant, the primary family automatically regains full use of the space without any further Town permitting. The code requires the design to preserve the building's one-family appearance as much as reasonably possible, and the Town can demand elevation drawings with a building permit application where alterations are proposed. Renting or occupying the unit by anyone other than a qualifying in-law is expressly prohibited, and the space must meet the habitable-space standards of Title 19 NYCRR, the New York State Building Code.

Violations & Fines

Renting an in-law apartment to a non-relative, building one without a permit, or exceeding the 600-square-foot or 30%-of-floor-area cap violates § 211-11 and is punishable under § 211-72: up to $1,000 or six months in jail for a first offense, escalating to $2,500 to $10,000 for a third offense within five years, with each week a separate violation.

Frequently Asked Questions

How big can an in-law apartment be in Greece?
Section 211-11B(12)(b) caps it at 30% of the one-family dwelling's gross floor area, not counting attached garages, or 600 square feet, whichever number is smaller. That keeps the apartment clearly secondary to the main house rather than a second full dwelling unit.
Who is allowed to live in an in-law apartment?
Only a resident member of the family occupying the main dwelling, or an in-law of that family, defined by § 211-5 as a relative by marriage. The homeowner must sign a notarized affidavit confirming the relationship, and renting the unit to anyone else is expressly prohibited under § 211-11B(12)(f).
Do I need a permit to build an in-law apartment?
Yes. Section 211-11B(12)(c) requires a building permit for any construction or remodeling to create the apartment, and the Town may ask for elevation drawings with that application if you're altering the exterior. A separate driveway or additional garage bays for the apartment also need their own permits.
What happens to the apartment if the in-law moves out?
Section 211-11B(12)(d) lets the family in the main part of the house take over the vacant apartment and use it as an ordinary part of their home without seeking any further permit from the Town, as long as they aren't renting it back out to a non-family occupant.

Sources & Official References

Other rules in Greece

All Greece rules

How Greece compares: Easiest Cities to Build an ADU·New York rules heatmap·Compare Greece to another location·View the New York accessory structures overview

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