The City of Littleton is taking a major step in allowing accessory dwelling units (ADUs) – a size-restricted, independent living space located on the same lot as a primary home – in all residential zones.
At its regular meeting on May 20, city council had a first hearing of Ordinance No. 09, Series 2025, which amends the city’s Unified Land Use Code to allow residents to have ADUs.
This move aligns Littleton’s zoning regulations with new state requirements and the city’s goals for housing diversity, such as the Envision Littleton Comprehensive Plan, according to Andrea Vaughn, Littleton’s senior planner.
The ordinance comes in response to Colorado House Bill 24-1152, passed in 2024, which mandates that municipalities permit ADUs — sometimes also known as “granny flats” or “in-law suites” — in all residential zones.
“HB 24-1152 is meant to address the housing crisis across the state as well as housing crises that are experienced by our aging population,” Vaughn said.
Since the adoption of Littleton’s land use code in October 2021, city staff, property owners and developers have worked within the code to manage site-specific applications. However, with the passage of HB 24-1152, Vaughn said the city recognized the need to update local regulations to comply with state law, and to address the growing demand for diverse housing options.
From June 2024 to March 2025, city staff conducted community engagement efforts, including study sessions with both the council and planning commission, a community survey, meetings with technical stakeholders and background research, according to the ordinance.
Littleton Planning Commission held a public hearing on May 12 and unanimously recommended the code amendment to city council.
In addition to permitting ADUs in all residential zones, the ordnance would bring more changes to ADU requirements:
- Maximum size for ADUs would increase from 750 to 1,000 square feet.
- Remove the requirement of constructing new parking for ADUs.
- Removes design standards that are otherwise not applied to primary housing buildings.
- Removes restriction that detached ADUs must be built on lots with alley access.
- Removes the “contained” ADU definition and standards. Contained-type ADUs is now “attached.”
- Allows ADUs to be built up to the height allowance of the zone district.
Vaughn said city staff believes this update will help meet the needs of a changing population, support intergenerational living and offer new options for affordable housing.
The ordinance passed its first reading with a five-to-one vote, with Councilmember Patrick Driscoll being the no vote,
“It’s not that I’m against ADUs, it’s against how (the state) is pushing it through and mandating it for the cities … hopefully (the state will) let us manage our own housing,” he said.
The matter will be considered for final approval on June 3, during which a public hearing will take place.