Accessory Dwelling Units or ADUs approved in unincorporated Arapahoe County

Accessory Dwelling Units, more commonly known as ADUs, have been approved in unincorporated Arapahoe County. The Arapahoe County Board of County Commissioners unanimously voted to approve ADUs, commonly called “granny flats” or “mother-in-law apartments.”

The regulations went into effect Tuesday. 

ADUs are smaller, independent living quarters either attached to a single-family home or located on the same lot as the main house. They are currently allowed in Aurora, Bennett, Cherry Hills Village, Englewood, Littleton and Sheridan.

“ADUs can help with affordability,” said Commissioner Jessica Campbell-Swanson in a statement. “We heard from residents across the county this is an option that residents have been waiting for.” Responding to voiced concerns, Campbell-Swanson referred to a comparative analysis that showed ADUs do not reduce property values or overextend infrastructure capacity; based on the county’s requirements, these structures will maintain community characteristics.

“These are going to be legitimate structures,” Campbell-Swanson said citing the requirements the regulations have in place for design and size. “I don’t share the concern that ADUs will stretch capacity or change the character of a neighborhood.”

Additional Information from Arapahoe County:

The new ADU regulations encompass elements designed to ensure successful implementation:

•Arapahoe County will permit both attached and detached ADUs in all agricultural and most residential zoning districts on lots that are at least 5,000 square feet.

•In urban areas, on lots of fewer than 19 acres, ADUs can have up to two bedrooms. Detached ADUs are required to be situated in the rear or side yard, behind the principal dwelling.

•Square footage limitations will be based on lot size and/or the size of the principal dwelling.

•Minimum design requirements, off-street parking, and owner occupancy of either the principal dwelling or the ADU will also be mandatory.

•Exceptions to ADU location, square footage, and bedroom limitations will be granted for properties of 19 or more acres.

•Homeowner association-managed neighborhoods may prohibit ADUs through private covenants.