Where are ADUs allowed:

ADUs are permitted in all zoning districts in Hudson, but only as an accessory use to an existing one-family dwelling. Each building lot may have only one ADU. You cannot build an ADU on a property that already has unresolved building violations unless the ADU project directly addresses and resolves those violations.

Owner Occupancy:

Hudson requires owner occupancy. The property owner must use either the main home or the ADU as their primary residence for at least 12 continuous months starting from the date the ADU’s certificate of occupancy is issued. Both the ADU and the main house must remain on the same tax lot under the same ownership.

Types of ADUs:

Attached, Detached, or Converted ADUs are permitted in Hudson.

Building Permits and Approvals:

A building permit and certificate of occupancy are required for any ADU. If your property is located in a local historic district, you’ll also need a certificate of appropriateness from the Historic Preservation Commission to ensure the exterior changes respect the historic character.

Size and Setbacks:

The ADU must meet the minimum size requirements for dwelling units under the City’s building code and cannot exceed the gross floor area of the primary home.
ADUs must also comply with the setbacks, height limits, and parking requirements that apply to single-family homes in their zoning district. ADUs are also allowed on lots that are pre-existing nonconforming in size.

Location and Site Design

• ADUs must be placed in the side or rear yard of the property - they are not allowed in the front yard.

• The design of an attached ADU should maintain the appearance of a single-family home from the street.

• The ADU must be built on a permanent foundation.

• A new, separate driveway access is not permitted; the ADU must use the existing driveway of the main home.

• Adequate water and sewage service must be provided in line with the Columbia County Department of Health standards.

  
  

Using Existing Structures

You can convert an existing nonconforming accessory structure—for example, a detached garage—into an ADU, as long as the footprint of that structure is not enlarged and all the other requirements listed above are met.