With your help, Boulder City Council passed much improved ADU regulations that we hope will lead to more affordable housing in neighborhoods across the City. While the ordinance did not include everything that Better Boulder advocated for, it is a good step forward. Better Boulder thanks all of you for telling your stories, speaking at meetings, attending the ADU Summit, making calls, writing postcards and email in support of better, more inclusive housing choices. You had a direct impact on this outcome over more than a year-long advocacy effort. Working together, we were able to achieve some important gains. We thank Aaron Brockett for making the motion, Jill Grano for her consistent advocacy in support of ADUs, Bob Yates and Sam Weaver for their collaborative efforts and all members of Council for the unanimous vote.

Changes to the ADU Ordinance:

Property owners can henceforth apply for two types of ADUs: Type 1 or Type 2. Type 1 ADUs are not subject to rent restrictions. The applicants for Type 2 ADUs must sign a recorded declaration agreeing to rent restriction not to exceed the rent for a similar unit affordable to people earning 75% of AMI—currently $1528 per month for a 1-bedroom. Henceforth, all ADUs and OAUs, whether part of the main home or detached from it, will be termed “ADUs.”

Requirements & Prohibitions Existing New Regs
  Type-1 Type-2
1 off street paved parking space YES NO NO
1 off street unpaved parking space   YES NO
Parking space can be in setback NO YES YES
Saturation Rate
No more than 10% of homes within 300 ft. can have ADU YES NO NO
All non-conforming structures are counted in the 10% YES NO NO
In RL, no more than 20% of homes within 300 ft. can have ADU NO YES YES
Only nonconforming structures and coops within the same zoning district are counted for saturation rate; and RL-1 and RL-2 are considering a single zoning district for purposes of saturation rate. NO YES YES
Detached ADUs
Detached ADUs are prohibited in RL zones YES NO NO
Lot Size Restriction
No ADUs on lots less than 6,000 sq. ft. YES NO NO
No ADUs on lots less than 5,000 sq. ft.   YES YES
Size of ADUs that are part of main house
Limited to lesser of 1,000 sq. ft. or 1/3 size of house YES YES NO
Limited to lesser of 1,000 sq. ft. or 1/2 size of house NO   YES
Size of Detached ADUs
Limited to 450 sq. ft. YES NO NO
Limited to 550 sq. ft.   YES NO
Limited to 800 sq. ft. or 1/2 the size of the main house     YES
Design Requirements for Detached ADUs
Design restrictions for roof pitches, garage doors and coverage YES NO NO
Miscellaneous Issues
No ADUs unless the main house is at least 5 years old YES NO NO
ADU permit cannot be renewed if someone is on waiting list YES NO NO
Short term rental of ADUs is permitted YES NO NO
Occupancy of ADUs cannot exceed two persons YES NO NO*
Exterior wall space is counted in determining ADU size YES NO NO
Appeal process to address absurd results** NO YES YES
Amnesty/penalty for existing ADUs that do not become legal** NO YES YES

The saturation rate was doubled to 20% although non-conforming structures and coops within the same zoning district as an applicant will be counted in the new saturation rate.

Council included an affordability requirement on some new ADUs with the rent cap to be set at the rent affordable to a two person household making 75% of the Area Median Income (AMI), unlikely to affect the vast majority of existing ADUs as they are naturally affordable and are already renting below this amount. While Better Boulder did not think this move was wise or necessary, we worked with the council members who advocated this change in order to structure it in a manner that we believe will be unlikely to discourage homeowners from adding ADUs. If this does turn out to be a problem, we will advocate for changes to this provision.

Property owners who want an internal ADU larger than one-third of the size of the house (but not to exceed 1,000 sq ft), or a detached ADU larger than 550 sq ft (but not to exceed the lesser of 800 sq ft or one-half the size of the main house), or who do not want to provide an additional parking space will have to agree to the rent cap.

While we would have liked to see more progress on relaxing the rules that get in the way of ordinary people helping to address our housing crisis, the ordinance passed will allow basement apartments and backyard cottages in many more neighborhoods without having to pave over yards for parking.

Better Boulder will continue to monitor these changes to see if they allow more people to add ADUs. If not, we will be back advocating for further changes. We will also continue to advocate for rules that allow other types of gentle infill in our neighborhoods, such as allowing ADUs additional occupancy, allowing a home to have both a basement apartment and a backyard cottage,and giving homeowners the right to build duplexes or triplexes as an alternative to McMansions.