BY SAM DESTEFANO

Recently Wash Park residents received postcards from the City of Denver regarding zoning ordinance changes to allow Accessory Dwelling Units (ADUs) in our neighborhood. To shed light on this important development, we sat down with architect John Ball, a long-time West Wash Park resident and urban planning enthusiast, to discuss the opportunities and challenges that ADUs present for our community.

The City of Denver sent postcards about zoning ordinance changes to allow ADUs in Wash Park. What’s all the buzz?

The nationwide excitement about the building of Accessory Dwelling Units (ADUs) on existing residential properties stems from their potential to positively impact individual homeowners, neighborhood dynamics, and broader urban issues all at once. Denver currently has a housing deficit of at least 20,000 to 70,000 units depending on whose numbers you trust. ADUs offer personal, community, and city-wide benefits while addressing the housing crisis.

Why is the city changing the zoning ordinance?

While currently not allowed in most of Wash Park or West Wash Park, ADUs are coming to Wash Park because of a recent state law that requires nearly all residential zoning districts in the state to allow ADUs.

The law, which goes into full effect on June 30, 2025, makes it easier for most Colorado residents to build an ADU. The city of Denver is currently in the process of updating its zoning ordinance to comply with state law. Approval by city council is expected in November, ahead of the state’s deadline.

ADUs provide a way to increase housing supply without drastically altering neighborhood character. ADUs make efficient use of existing infrastructure and land, thus promoting sustainable urban growth.

Apparently, ADU development has been of interest to the city for some time. Can you explain?

The city’s interest in part stems from the housing supply increases other cities have achieved by allowing ADUs on single family lots. Los Angeles, Portland, and Seattle are notable examples.

In Los Angeles the number of ADU permits in LA increased by 202%. In 2021, ADUs accounted for about 22% of all planned new housing. Portland’s reforms led to increased permits which jumped by 34% between 2021 and 2022. Seattle ADU permits outpaced the construction of single houses for the first time.

For the past two years, Denver ran a pilot program on the west side of Denver to promote ADUs with financial and other incentives including pre-approved plans. Approximately 1% of existing residential properties in the pilot area built an ADU. 

Why would someone build an ADU?

In general, property owners build ADUs for two reasons. The first is to provide housing for an extended family member such as a parent or grandparent. The cost of building an ADU, which can range from $300,000 to $800,000 could be less than housing a relative in a senior care center. ADUs enable families to house aging parents or adult children, fostering closer family ties and providing affordable living options

The second reason to build an ADU is to create a rental income stream and/or build wealth by increasing the value of the property. As mortgage interest rates continue to fall, this option will gradually become more viable given that most ADUs are funded by refinancing the entire property via a construction loan coupled with permanent financing. Homeowners can create an additional income stream by renting out their ADU, potentially making homeownership more affordable.

A related scenario occurs when a homeowner builds an ADU, occupies the ADU, and then rents out the original main house. This works especially well for empty nesters and/or seniors that want to make it possible for family members with children to occupy the larger main home. 

What are the challenges of ADU construction in Wash Park?

Building an ADU in Wash Park, which can range in size from 500 to 864 square feet, will be a challenging proposition owing to several factors including finance, utilities, the limitations of Denver’s form-based zoning ordinance, parking, obtaining a building permit, and the practicalities of building a small house and garage in a backyard alongside a very narrow alley with overhead power lines, and the general hassle factor.

The modified Denver zoning ordinance will allow 2-story ADU/garage configurations within a gable roof form. On a typical 37.5’ wide Wash Park residential lot, an ADU over a two-car garage will be feasible. The wider lots will be easier, while the 25’ wide lots will be more of a challenge.

Bringing utilities to the ADU will be a challenge in almost all cases. This is because water and gas comes from the street, and sewer is located in the alley. A related issue is that many older residences still have water service delivered via lead pipes (though this may be a replacement opportunity in disguise). Similarly, residences that still have overhead power drops from the alley to the back of the main house may require an underground service upgrade. All these could be paid for in the overall refinance of the property.

What impact do you believe ADUs will have on Wash Park and what does the future hold?

One major benefit of ADU development may be the gradual beautification of alleys in the neighborhood. Our alleys are somewhat blighted by the overhead power lines, a vast number of wheelie-bin dumpsters, the poor quality of pavements, and the general neglect in some locations. These are all issues for urban planners focused on the larger context of neighborhood improvement.

Over the next decade or two, ADUs will likely create gradual gentle densification and diversification of the Wash Park neighborhood. Given the high level of aesthetic appreciation amongst most residents, the outcomes could be exemplary.

John Ball is a Colorado licensed architect. He holds a BFA from Drake University, an M.Arch from the University of Oklahoma, and a PhD in Environment, Design, and Art from Arizona State University.