Not the same as the City of Canandaigua. The City of Canandaigua has no ADU rule. Leaders discussed one in January 2026 and did not move it forward. Do not confuse the city with the Town of Canandaigua, which does allow ADUs. See Ontario County. Check which one is on your property tax bill.
The Town of Canandaigua treats an ADU much like an addition: one attached or detached unit, sized by the normal house rules, with the owner on site and a recorded agreement. No special permit is required by this section.
The code describes a way to approve an ADU with a permit, without a special public hearing for the ADU itself.
Whether any of this applies to your lot depends on your zoning district and your property.
The rules we found
| What the code says | Allowed with a permit |
|---|---|
| Detached (backyard) unit | Yes, at least 10 ft from the house and meeting the setbacks and height for a home in that district |
| Inside or attached | Yes. Attached units need an inside passage to the main home; any separate outside door cannot face the front |
| Size limit | No separate cap; the district's bulk and area rules for a single-family home apply |
| Bedrooms | None stated |
| Owner must live on site | Yes. The owners of record live in either unit |
| How approval works | Building permit and a recorded agreement before the certificate of occupancy. Site plan review is generally not required for a house expansion with an accessory apartment, except in the Residential Lake District (§220-64B(1)) |
| Other rules | Allowed wherever a single-family home is allowed, on a lot whose existing home has a certificate of occupancy (the town's sign-off that it can be lived in). One per lot, sharing one service and one meter per utility with the house, with one extra parking space and a single driveway entrance. Not allowed on a lot that already has a tourist home, B&B, rooming house, home business, another ADU or an apartment building. |
Code section: §220-9U Accessory dwelling units; §1-17 definition; §220-64B site plan exemptions. §220-9 amended many times; latest listed amendment July 21, 2025 (Local Law 4 of 2025).
What this means for your plans
- The owner has to live on the property. If you plan to move away, spend winters somewhere else or sell, read the owner rule above closely. Renting and owner rules.
What we’re still confirming
- 2025 Ordinance Committee agendas list ADU topics; any pending change was not checked
- Whether a single shared utility meter is practical for a detached unit
Before you spend money on drawings
- Confirm the Town of Canandaigua governs your lot: it should be the municipality on your property tax bill.
- Find your zoning district on the municipal zoning map; the rules above can differ by district.
- Call or write the code office with your address and what you’re picturing, and ask for the answer and the code section in writing.
- On septic or a well? Ask the NYS Department of Health’s Geneva District Office (315-789-3030) whether the system can serve an extra bedroom. On public sewer? Ask your sewer district.
Our guides explain the approval process, site and utility checks and what an ADU costs.
Sources
General information, not legal advice. The Town of Canandaigua decides what can be built on your property.