Zoning Code Updates for Multifamily Parking and Accessory Dwelling Units (ADUs)

What you need to know: How our zoning code is changing in response to state legislation

In 2024, the Colorado State Legislature voted to enact two laws affecting local level planning, House Bill 24-1304 and House Bill 24-1152. The focus of House Bill 24-1304 is to allow for reductions in multifamily parking in areas that are well-served by transit. The goal of House Bill 24-1152 is to promote the development of Accessory Dwelling Units (ADUs) by allowing them as an accessory use on all lots that are zoned for single-family detached dwellings.

As a result of both bills, the city of Aurora is updating the zoning code to comply with the standards set forth by the bills. The passage of both bills presents an opportunity for the city to assess the current zoning code and make changes for the benefit of residents and visitors. Continue reading to learn more about how the city is addressing these code updates.

Use the questions section on this page to ask any questions that you might have, and send your comments or concerns to the contacts in the Who's Listening section.

Overview of House Bill 24-1304: Multifamily Parking

In 2024, the Colorado state legislature voted to enact House Bill 24-1304 to allow reductions in parking in areas that are well-served by transit. The bill prohibits cities like Aurora from enacting or enforcing minimum off-street parking requirements for multifamily housing within Applicable Transit Service Areas. Applicable Transit Service Areas are generally defined as areas within one-quarter mile of a bus or light rail stop. The following is an overview of the requirements in the bill:

• New multifamily residential development, regardless of whether it is a freestanding residential building or part of a mixed-use building or development that also contains some non-residential uses, will not be required to provide off-street parking if it is located in an Applicable Transit Service Area
• The Adaptive Reuse of an existing building for completely residential purposes, or the Adaptive Reuse of an existing building for a mix of uses in which at least 50 percent of the resulting use is residential, will not be required to provide off-street parking if it is located in an Applicable Transit Service Area

Proposed Changes to Aurora's Unified Development Ordinance

To demonstrate compliance with the requirements of HB24-1304, the city is amending Section 146-4.6 of the UDO, which outlines development standards pertaining to parking in Aurora. The following are the main changes to the UDO that are important for residents to know:

• The applicability statement will be modified to reflect the exemption from minimum parking standards for qualifying multifamily and mixed-use developments located in Applicable Transit Service Areas.
• Expansions of existing buildings that result in at least 50 percent of the building as multifamily, or changes in use that include at least 50 percent of the resulting use as multifamily, will be exempt from providing additional off-street parking if located in Applicable Transit Service Areas.
• Table 4.6-1, which outlines off-street parking requirements for all uses in the city, will be modified to reflect that new multifamily dwellings meeting the requirements above will have no parking requirement. All other uses will remain unchanged. Multifamily dwellings that are not located in Applicable Transit Service Areas will still require one parking space per dwelling unit, plus applicable guest parking spaces.
• Accessible parking and bicycle parking requirements for multifamily within Applicable Transit Service Areas will be clarified.

A draft version of the proposed amendments to Section 146-4.6 will be posted here when available.

Benefits of Reducing Parking for Multifamily Housing

Requirements for minimum amounts of off-street parking limit the amount of housing that can be built on many sites, and many parking spaces provided for residential developments remain unused. One recent study of multifamily housing near RTD stations found that approximately 40 percent of parking spaces for market rate housing and 50 percent of parking spaces for income-restricted housing are unused by residents at peak times. Reducing parking will have many benefits for Aurora residents:

• Housing and transportation costs represent the highest household costs for most Colorado residents. Minimum off-street parking requirements directly add costs to housing and indirectly increase transportation costs by necessitating higher rates of driving and car ownership (see Figure 1).
• Requiring off-street parking minimums creates competition for space between housing and parking. This relationship limits the ability for new residential developments to provide unit counts adequate to combat existing demand for housing. By providing more off-street parking, density is reduced, and the cost of each unit becomes higher (see Figure 2).
• Higher parking minimums create additional development costs. These costs are passed on to the end user, contributing to inflated housing prices and overall lack of affordability. Studies in Colorado have found that parking adds an estimated $225 to monthly rent or $18,000 to home sales.

Overview of House Bill 24-1152: Accessory Dwelling Units

The goal of House Bill 24-1152 is to promote the development of Accessory Dwelling Units (ADU) in Colorado. The bill requires in Colorado to permit Accessory Dwelling Units wherever the zoning code allows for Single-Family Detached Dwellings. Main items of the bill include:

• Permitting one ADU as an accessory use to a single-family detached dwelling.
• Requiring approval ADUs through an Administrative Approval process.
• Requiring fewer restrictions: Design and dimensional standards to be no more restrictive than the standards for single-family detached dwellings.

What is an Accessory Dwelling Unit?

ADUs are smaller living spaces accessory to the primary dwelling, or home that is designed to provide independent housing, and typically include a kitchen, bedroom, bathroom, and living area. Many may know ADUs by a different name such as a granny flat or an in-law suite. ADUs are often used for a variety of purposes, such as rental income, housing family members, and affordable housing options. Common types of ADUs include garage conversions, basement apartments, and small standalone cottages. An ADU can be internal, attached or detached from the dwelling.

Proposed Changes to Aurora's Unified Development Ordinance

The following are the main changes to the zoning code that are important for residents and homeowners to know:

• ADUs can be built in more zone districts: ADUs will be permitted to be in R-R, R-1, R-2, R-3, R-4, OA-R1, OA-R2, MU-A, and APZ Zone Districts. Visit this link to find out what zone district your property is located in Aurora.
• ADUs will no longer require a Public Hearing and Approval from the Planning and Zoning Commission: ADUs are required to be administratively approved. This means an ADU can gain approval by acquiring specific building permits.
• Updated ADU code requirements: Specific sections related to ADUs, such as the "Use specific standards, dimensional standards, and the permitted use table," will be updated to comply with the legislation.

Benefits of ADUs

Accessory Dwelling Units offer a variety of benefits to both homeowners and the broader community. For homeowners, ADUs can provide an opportunity for rental income, which can help offset mortgage costs or increase property value. They also offer a flexible housing solution for family members, such as aging parents or adult children, allowing them to live nearby while maintaining privacy. For the city as a whole, ADUs can help address housing shortages by creating more affordable living options without the need for large-scale new developments. Additionally, they promote sustainable growth by utilizing existing infrastructure and reducing urban sprawl. Overall, ADUs contribute to a more diverse, resilient, and connected community.

The zoning code update furthers the vision and goals of the city’s Comprehensive Plan, Aurora Places. Aurora Places acts as a guide to provide a long-term vision for the future of land use within Aurora’s community. One of the seven goals from Aurora Places is Housing for All. High-quality housing options enable people across all socioeconomic levels, cultural identities and stages of life to establish and manage households. Several strategies from this goal that relate to ADUs are listed below:

• Integrate housing of varying types and prices into placetypes throughout the city to create lively and diverse neighborhoods.
• Allow accessory dwellings to accommodate extended family arrangements or generate income to accommodate rising housing prices.
• Encourage the construction or rehabilitation of homes for downsizing households, including single-story, shared housing, multigenerational and other senior­ friendly housing types.
• Promote resource-efficient development.

To learn more about the benefits of ADUs, please go to the Important Links: Accessory Dwelling Units section of this page.