Every City has different rules and regulations for Accessory Dwelling Units, or ADU's for short.
A recent Colorado Senate Bill 23-213 (SB23-213) included new rules that would lift many of the limits that local jurisdictions placed on ADUs. One proposed change allowed ADUs for any property that is zoned for Single Family in an effort to expand housing options across the state.
While it's still in legislation, it's a clear indication that ADU's will get easier in the future. Some Cities in Colorado have already taken their own steps to revise ADU Rules, the two we will focus on are Denver and Boulder.
City of Denver
Denver is now working towards increasing the amount of ADUs by making recommendations to for changes to the Blueprint Denver Program.
Blueprint Denver is a city-wide land use and transportation plan that provides a strategy to enhance quality of life in Denver by promoting and enhancing the relationships between Communities and Transportation.
These recommendations come from Community feedback and include the following:
Increase in Height
New rules would allow Detached ADU's to have 2 Stories, where currently they are restricted 1 1/2 Stories. The Bulk Plane measurement limit is increased for narrow lots, which allows for taller structures near Side Yard Lot Line.
There would be different Setbacks depending on the height of the ADU. Additionally, the Side Yard Setbacks will now match the Principal Structure
Decks and Balconies
Decks and Balconies on a Detached ADU overlooking an Alley are allowed.
The Maximum Floor Area was increased to 865 from 650 SF for Lots under 6,000 SF.
ADU's are now allowed for Duplex and Multifamily Units. Restrictions for converting an existing garage to a Detached ADU have also been relaxed.
City of Boulder
Boulder passed Ordinance 8571 in May, which removed many of the restrictions for an ADU, with the changes coming into effect September 1st.
The biggest change (in my opinion) is removing the separate ADU Zoning Review, which was an additional step prior to the Building Permit to determine if an ADU is allowed. Now, you can go straight to Building Permit with no separate approval required, saving time and money for Owners. Additional changes include:
Changes to Floor Area Definition
Removed the current stipulation that the Floor Area of an ADU shall include the egress path, such exterior stairs, walkways, interior hallways or stairs.
This meant that if you had a 500 SF Upper Floor ADU and 70 SF of Exterior Stairs, your total ADU Area would be 570 SF.
Another big change involved the quantity of ADU's. Previously, ADU's were limited to only 20% of the Homes in an area. This 20% Saturation Limit has been removed, and ADU's are allowed outright.
The maximum size of ADU's were increased across all types. Detached Units grew from 550 SF (Market Rate) to 800 SF and some Attached Units were increased to 1,200 SF from 1,000 SF.
Following the 2021 Marshall Fire, Boulder County adopted Article 19 which provided regulations to those directly affected by the Marshall Fire. While it mainly covered the reconstruction process, it also included some new ADU rules.
It's likely we will see other jurisdictions add rules or language to their Code in regards to Accessory Dwelling Units. Many locations are asking for resident feedback as they look to update their policies, such as Westminster and Denver.
Feel free to message us if you want to learn more about an ADU for you!