The Boulder City Council directed city planners last week to begin drafting a package of code changes that would increase housing density in neighborhoods across Boulder. One of the goals is to drive down housing costs by allowing property owners to convert single-family homes into duplexes and triplexes.
The proposed changes are the latest stage in a yearslong “zoning for affordable housing” project initiated by councilmembers in January 2022.
Late last year, councilmembers amended city code to make it easier for developers to build smaller housing units. They also eliminated single-family zoning in all the city’s zoning districts. However, councilmembers did not change rules related to residential density. As a result, only property owners with relatively large lots are able to convert a single-family home into a duplex.
The next phase of this project will modify density rules. To do so, city staff have proposed reducing the minimum lot area per dwelling unit requirements in certain zoning districts. These changes aim to allow property owners to turn single-family homes into duplexes without necessarily allowing them to subdivide their properties.
For instance, in the RMX-1 zoning district — which includes neighborhoods such as Whittier, University Hill and Newlands — officials have proposed reducing the minimum lot area per dwelling unit requirement from 6,000 square feet to 3,000 square feet. Similarly, in the RL-1 district, which encompasses lower-density areas primarily composed of single-family homes, the proposal would lower the minimum from 7,000 square feet per dwelling unit to 4,000 square feet.
City planners are seeking to discourage subdivisions and redevelopments. Floor area ratio maximums, which effectively restrict the overall size of a building, would have to remain the same as the original single-family home. This means a property owner would not be able to replace a single family home with a larger duplex or triplex. Off-street parking requirements would also apply to any additional housing units.
City planners are expected to report back to councilmembers with a draft ordinance as soon as this fall, according to a city staff memo.
Some councilmembers suggested city planners should allow even greater density in certain zoning districts. However, the overall density of neighborhoods is bound by the Boulder Valley Comprehensive Plan, a land-use plan approved by the city and Boulder County. Councilmembers may seek to amend these requirements as part of an update to the plan expected in the next couple of years.
Is there any evidence to support the idea that increased density creates more affordable housing? This needs to be balanced against the negative impacts of this approach or quality of life will be reduced.
Of course not, density has never led to affordable housing; Boulder already has the highest density in the state. There is zero evidence anywhere that the market can create more affordability by building more in an expensive town like Boulder it’s all a pipe dream created by urbanists; most of whom have no training or experience in economics.
There is plenty of evidence. Minneapolis and Austin are some recent examples. Overwhelming evidence points to lower rents when the ratio of the value of buildings on a parcel to the value of the underlying land is higher. Right-sizing density to demand (which would mean more density in Boulder) is also associated with more sustainable city finances, healthier lifestyles, less carbon output per capita, less economic segregation, and more disposable time. Regardless upzoning is an easy way to address the housing crisis and create affordable housing. When the value of land alone for single family properties in Boulder are near or at $1mil +, unlocking the ability to split land among more homes will easily create housing options that are affordable to the people who are currently priced out of Boulder.