ADU Zoning in Darien, Connecticut
What Darien allows for accessory dwelling units — permitted zones, size limits, parking, rental rules and utilities. Boxx ADUs designs and builds ADUs in Darien and across Fairfield County. Call us to talk through your property, or send us a message.
Which zones allow ADUs?
ADUs are allowed in residential zoning districts R-2, R-1, R-1/2, R-1/3, or R-1/5. A single ADU may be established on any lot with an existing or proposed single-family dwelling.
What types of ADUs are allowed?
Attached or Detached.
What are the size/floor area requirements?
Maximum ADU sizes and floor area
- 700 square feet if part of or attached to the principal dwelling.
- 1,000 square feet if detached and separate from the principal dwelling.
- Less than 30 percent of the total finished floor area of the principal dwelling plus the ADU.
How many parking spaces?
Darien requires one parking space for a studio or one bedroom and one additional parking space for each additional bedroom in the ADU.
What are the rental requirements?
Long-term and short-term rentals that are greater than 90 days are allowed.
Owner-occupancy is required.
What about utilities, sewer or septic?
Utilities and sewer tie into the main house. Septic is job-specific. New and separate utilities are allowed.
Summarized for convenience and current as of publication. Local regulations change — confirm details with the town before relying on them.