What is Upzoning?

Zoning laws govern how property can and cannot be used including the density (e.g., number of housing units per acre) of housing allowed within various areas in a community. Amending local zoning laws to allow for more housing units to be developed in previously more restrictive areas can help increase a community’s housing supply and provide a more diverse range of housing options. This approach is known as upzoning. While upzoning does not create new housing, the process removes a significant barrier to building new housing and can greatly incentivize new housing development projects. Upzoning is also particularly appropriate in areas with existing water and sewer infrastructure, where projects can take advantage of these public investments can reduce development costs.

Upzoning means an increase in density of housing units relative to what is currently allowed. In urban areas, upzoning may mean higher building heights with more units, and in more suburban or rural areas upzoning may mean allowing duplexes or multifamily units in districts zoned previously for single-family housing. It can also mean reducing minimum lot sizes or granting density bonuses for affordable housing units. Whether urban or rural, upzoning can be designed to take advantage of lands that are more suitable to development and close to public facilities, services, or job opportunities. Upzoning generally leads to lower housing costs and can include a focus on preserving open space. Upzoning coupled with mandatory affordability requirements is a way to develop new housing while meeting the housing cost challenges for many communities.

Mandatory Affordable Housing

In addition to increasing the density in certain areas to promote compact walkable neighborhoods, communities can also require the inclusion of affordable housing within new developments in these areas. This “mandatory affordable housing” or “inclusionary zoning” helps to ensure affordability of some or all of the new housing being built as the community adds to its housing stock. Inclusionary zoning is often applied to developments of a certain size (i.e., projects with more than 10 units) in which a percentage of units must be affordable to households under set income limits.

Benefits of Upzoning:Gentle Density Example

  • Efficiency of infrastructure and lower public costs – The fixed costs of infrastructure are spread to a higher number of businesses and households. Be it roads, sidewalks, or water and sewer upzoning takes advantage of the public investment in these improvements and enables private investment where they are not present.
  • Protection of open space – Creating compact neighborhoods by encouraging density in defined areas makes it possible to keep more sensitive areas or important community resources as open space even as the population continues to grow.
  • Economic and cultural vibrancy – Neighborhoods with higher density are essential for the establishment and survival of many commercial establishments including neighborhood stores and restaurants, cultural institutions, and public services such as libraries and public transportation.
  • Reduced environmental impacts – Per capita greenhouse gas emissions typically are lower in more dense, location-efficient developments. People drive less, building designs become more efficient, and the delivery of community services from garbage, to mail, to emergency response become more feasible and cost effective.
  • Social benefits – Well-designed, compact residential developments can support mixed-income and diverse communities, which provides the chance for interaction between different social groups, an important piece of socially inclusive communities.
  • Supports community identity – Housing that is spaced far apart can inhibit social interaction between neighbors. Well-designed, compact residential areas with intentionally designed communal space fosters community.

Every community should identify areas where increased density makes sense. Clear winners are areas near public schools, parks, transit and commercial sites where adding mixed use residential buildings is possible. Duplexes have been dubbed as gentle density and encouraging them in single family districts can have a dramatic effect on affordability while preserving neighborhood character.

Best practices to ensure upzoning provides the maximum benefit to a community and results in the creation of more housing units:

  • Involve stakeholders in the rezoning process: Local residents, business leaders, and others should be part of the process in order to ensure upzoning is in line with community goals.
  • Tailor upzoning to local conditions: Communities need to decide where they want to see pockets of density, how much density is needed to satisfy housing supply needs, and how to upzone in a way that is aligned with community goals.
  • Allow mixed-uses in areas within upzoned districts: Increasing density in a neighborhood means there are more people who need goods and services, and in turn, support local businesses. To ensure upzoning results in more walkable communities, there needs to be destinations for people to walk. As communities upzone, they should consider where it makes sense to create mixed-use areas that include residential and commercial uses.
  • Reduce parking requirements: Studies show that standard parking requirements are excessive and add to the cost of development, a cost which is often passed on to homeowners and renters.
  • Streamline approval process: As a community goes through the process of upzoning, update the approval process to streamline projects that meet certain project standards, include an affordable housing component, meet design and architectural guidelines, and offer certain community benefits.
  • Ensure upzoning does not result in structures that feel “out of place” in a neighborhood by implementing design guidelines. Guidelines might specify architectural style and materials as well as require that buildings on the edge of a zone must “step up” to maximum allowable height.

Minimum Criteria for Upzoning:

  1. Housing Capacity Increase: The upzoning changes undertaken by the municipality should increase the total number of potential housing units that could be built in the community by making zoning less restrictive and allow for more types of housing (e.g., duplexes, Accessory Dwelling Units) to be built in more places. The zoning updates should increase the total number of potential housing units that can be built by a factor of three.
  2. Mandatory Affordable Housing (MAH): The zoning change is paired with a MAH policy in which new developments with six units or more include a minimum of ten percent of units as affordable for households with incomes for rental units at or below 80 percent of the county area median income (AMI) and at or below 100% for home ownership. Income qualifying households should not pay more than 30 percent of household income toward housing costs. Affordable units should not be visibly distinguishable from market rate units. Specific provisions regarding affordability such as the period of affordability, income limits, and rental and resale restrictions should be defined in deed covenants.
  3. Zoning Change Consistency: As part of the upzoning process, check other zoning and building code requirements and modify height limits, lot coverage, floor area ratio requirements, and occupancy restrictions as needed to ensure that upzoning promotes an increase in density. These other zoning requirements can inhibit an increase in units in upzoned areas.
  4. Accountability: Designate the responsibility of tracking, monitoring, and enforcing compliance for housing units created under the upzoning policy to a municipal staff member or department. Responsibility includes tracking the following:
    • development proposals
    • the construction of new units
    • the number of affordable units
    • the sale or rental of any affordable units with income limits as part of the MHA
    • An annual audit should be conducted where a sample of affordable units (twenty-five percent) is checked to ensure rents and occupancy comply with the MHA policy
  5. Affordable Housing Registry: Create a registry for affordable units created as part of the MHA. Building owners must update contact information on an annual basis or face fines. They must comply with affordability provisions or certificate of occupancy will be invalidated.


New Rochelle, NY, Downtown Overlay Zone (DOZ)

The City of New Rochelle has rezoned nearly 300 acres of its downtown area to encourage the development of mixed-use residential and commercial development. As part of the DOZ, all projects are required to provide 10 percent of residential square footage as affordable for households at 80 percent of AMI, or to pay into the city’s Affordable Housing Fund according to a set formula.

Additional Resources:

Downtown Overlay Zone


Minneapolis, MN, 2040 Plan (Zoning Update)

Through the adoption of the 2040 Plan, the City of Minneapolis eliminated single-family zoning throughout the city. Prior to the update, 70 percent of the city’s land was zoned for single-family. Under the new zoning duplexes and triplexes are allowed on formerly single-family lots. Under the same policy, higher density levels are allowed near train stations, and parking requirements were eliminated. The policy also includes an inclusionary zoning provision which mandates apartment buildings includes a 10 percent set aside for moderate income households.

Additional Resources:

Minneapolis 2040 Comprehensive Plan

Resolution No. 2019R-308, File No. 2018-00770

State of California SB-9

In 2021, the State of California passed SB-9, a state-wide bill that allows “A proposed housing development containing no more than two residential units within a single-family residential zone shall be considered ministerial , without discretionary review or a hearing, if the proposed housing development meets (a set of requirements).”

Additional Resources:

Bill Text -SB-9: Housing development: approvals

Washington D.C Inclusionary Zoning

Under D.C.’s Inclusionary Zoning policy, new residential developments with ten or more units or rehabilitation projects that are creating ten or more units in an existing building or addition must include eight to ten percent of the residential floor area be set-aside for affordable units.

Additional Resources:

Inclusionary Zoning (IZ) Affordable Housing Program

Administration Guidelines of Affordable Housing Units

Maximum Income, Rent and Purchase Price Schedule for 2021

St. Petersburg, FL

Through the creation of a Neighborhood Traditional Mixed Residential (NTM) zoning district, the City of St. Petersburg is allowing an increase of low to medium density in some neighborhoods. Under the new zoning, duplexes, triplexes and smaller dimension homes such as AUDs are now allowed as of right with a limit of no more than 30-units per acre. Design standards will ensure new buildings are in line with standards of existing neighborhoods.

Additional Resources:

St. Petersburg, FL Model Ordinance