The Boulder City Council may consider new rules that make it easier to build ADUs in Boulder's single-family home neighborhoods, such as Mapleton Hill. Credit: John Herrick

The Boulder City Council last week gave city planners deadlines for coming up with policy recommendations to help boost the city’s housing stock, particularly in single-family home neighborhoods. 

This includes loosening restrictions on accessory dwelling units, or ADUs, to make them easier and cheaper to build. ADUs — also known as granny flats, backyard cottages or in-law apartments — can be rented out or used for family and friends. They are typically built in backyards, garages and basements, and can increase density in single-family home neighborhoods, helping chip away at the city housing crisis by providing more relatively affordable housing. 

The city council directed city staff to consider eliminating saturation limits on how many ADUs can be built in neighborhoods. While the policy has not blocked many ADUs from being built, city staff have said the restriction creates a perceived barrier that prevents residents from trying to build them. City staff have said they are not aware of any other municipalities that have saturation limits for ADUs. 

Other policies to be considered include increasing the size limits for ADUs, simplifying the process for measuring square footage, and clarifying the code to make it easier for residents to understand the rules, including the existing requirement that the property owner has to live on site in order to have an ADU. 

City staff are planning to present policy suggestions to city council by July 2023. Additional reforms may be considered at a later date, too. 

But one policy change not to be considered, at least in the near term, is eliminating parking requirements. Earlier this month, the Housing Advisory Board sent a letter to councilmembers recommending they eliminate a requirement that owners of market-rate ADUs provide at least one parking space, among other policy suggestions. 

Such requirements can make it more costly or burdensome to build ADUs. Transportation advocates also argue parking minimums reward people who own cars at a time when cities are rethinking streetscapes to reduce car culture for safety, climate and other reasons.

Under the city’s current ADU rules, people can build them without parking as long as the owner makes them “affordable” to renters. This means capping rent and utilities so that people earning up to 75% the city’s area median income ($89,000) spend no more than a third of their income on housing. This equals about $1,646 per month for a studio. (The average rent for a market-rate ADU is $1,626 per month, according to city officials.)

“There is always a way to create an ADU without any parking,” Mayor Aaron Brockett said in an interview on Friday. “You just have to sign a covenant that says you won’t rent it above a certain amount. It’s not a huge sacrifice.” 

Eliminating parking from ADUs would likely stoke even more pushback from residents concerned about potential nuisance issues and impacts on neighborhood character. Last week, councilmembers received a letter from the Martin Acres Neighborhood Association steering committee urging them to hold off on lifting any restrictions on ADUs. 

“Due to our proximity to CU, our neighborhoods have very high percentages of rentals, particularly student rentals. Even without this proposed ADU density increase, we already struggle with exponentially more daily quality of life issues: noise, congestion, much greater daily churn (loud comings and goings at all hours of the day and night), trash, and parking issues,” the letter states. 

Michael Leccese, chair of the Housing Advisory Board, said part of the motivation for suggesting eliminating parking was to reduce hurdles for property owners in neighborhoods where parking’s not an issue. For areas that do have parking challenges, he said, the lack of parking might help reserve housing for people who don’t own cars. 

With other policy reforms under consideration, Leccese said he understands why councilmembers did not want to eliminate parking. 

“I think it is very reasonable for them to think that through very carefully. It could be a hot-button issue,” he said. “It may not be an issue worth fighting over.” 

City councilmembers have a long list of other policy changes to increase the availability and affordability of housing in Boulder. Their ambitious agenda comes at a time when city planners have said they are stretched thin due to staffing issues, forcing councilmembers to be selective about their priorities. 

In the last year, four senior planners have departed from the Department of Planning and Development Services, city officials said. So did the department’s director. Meanwhile, the number of building permits the department has to review is historically high, Brad Mueller, the city’s planning director who was hired in June 2022, told councilmembers. 

As a result, much of the discussion last Thursday involved deciding which policy reforms to advance and which to delay. 

‘We’re not going to make everybody happy’ 

The city’s planning department is scheduled to finalize a study in 2024 on whether to connect water, sewer and other services to a undeveloped area north of the city known as the Area III Planning Reserve. The area could present a rare opportunity to build a relatively large amount of housing, including affordable for-sale housing. Another opportunity for new housing is the second planning phase for the east Boulder neighborhood known as Boulder Junction, a commercial area the city hopes to turn into mixed-use housing. 

The planning department is also reviewing zoning reforms aimed at creating more deed-restricted affordable homes and smaller homes that are more affordable than typical market-rate units. 

The most controversial issue on the department’s to-do list is considering changes to the city’s occupancy laws, which limit the number of unrelated people who can live together. The city council directed city staff to consider changes to the city’s occupancy laws earlier this year after a 2021 ballot measure to lift the restrictions failed by a 48% to 52% margin. (Fewer than half the city’s voters cast ballots that year.) 

The measure would have increased the occupancy limits from three people — which is the limit in single-family home neighborhoods — to at least one person per bedroom, plus one. 

The city’s work on this issue has already been delayed by months. Some councilmembers want to move ahead as quickly as possible. 

“Occupancy is, in my mind, one of the ways we can provide more housing options for people the fastest,” Councilmember Lauren Folkerts said during the meeting. “Since we’re in this housing crisis, it’s important for us to do the things that will make change for our community quickly.” 

Next year, city staff plan to create a working group, likely to include neighborhood associations’ concerned about lifting occupancy limits, to discuss policy reforms. Some councilmembers suggested skipping the working group to save time. Others worried that would upset neighborhood groups. 

Councilmembers are expected to provide feedback to city staff on how to proceed early next year. 

“Regardless of what happens, we’re not going to make everybody happy,” Councilmember Nicole Speer said. “We can take some of the heat.” 

“We’re really in a situation where a lot of good people are leaving our community and we need to figure out how we can get more folks to stay,” Speer added, “as quickly as possible.” 

John Herrick is senior reporter for Boulder Reporting Lab, covering housing, transportation, policing and local government. He previously covered the state Capitol for The Colorado Independent and environmental policy for He is interested in stories about people, power and fairness. Email:

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