Ridgefield, CT Accessory Structures: ADU Rules (2026)

2 of the Zoning Regulations lists the accessory dwelling unit as a use permitted with a Zoning Permit issued by the Zoning Enforcement Officer, not a discretionary Special Permit, since the Commission delegated that authority effective July 1, 2016 and again June 7, 2019. Only one ADU is allowed per lot, and none may be approved accessory to a two-family dwelling, other multi-family use, or a common interest community. The lot must meet the zone's minimum lot area or be legally nonconforming, and both dwellings must be served by public water or a private well and by municipal sewer or a compliant private septic system; on lots under half an acre without municipal sewer, the ADU must be attached to or inside the principal dwelling.

The owner must live on the premises and hold at least a one-third fee interest. Size is tied to the main house: 900 square feet of habitable area if the principal dwelling is under 3,000 square feet, rising to 1,200 square feet for larger houses, with the main house's square footage taken from the Assessor's field card. The unit is capped at two bedrooms and at least one side must sit at or above grade. No additional curb cut may be created, so the ADU shares the existing driveway access with the principal dwelling.

3 lets an owner rent to a tenant at or under 80% of area median income under CGS § 8-30g, with a recorded ten-year deed restriction, and waives the zoning permit construction fee entirely.