Infill Development

The Governor’s Office of Planning and Research (OPR) defines infill development as “building within unused or underused lands within existing development patterns, typically but not exclusively in urban areas.” The benefits of infill development are multi-faceted. Infill development provides opportunities to build housing in accessible, high-resource areas of a city. It can also further sustainability goals, including reduced greenhouse gas emissions, air pollution, and stormwater pollution. Locating housing on infill sites rather than on greenfield sites generally reduces the vehicle miles traveled (VMT) for residents, resulting in lower emissions and cleaner air. Further, infill development minimizes the construction of new impermeable surfaces that contribute to stormwater runoff. Preservation of open space and agricultural land is another clear benefit of infill development. Finally, infill development ties into the existing infrastructure rather than creating a need to build new infrastructure, resulting in both cost and resource savings. 

Metrics jurisdictions can use to identify underused sites include low lot coverage or floor area ratios, low improvement ratios (value of improvements to land value), and age of structures on a site. Sites with declining or outdated business types may also be considered underused. Proactive identification of underused sites by the city sends a positive message to developers about where opportunities for development exist and can lead to reinvestment and revitalization.

Development on infill sites can be more challenging than on undeveloped land due to the necessity of working with existing on- and off-site conditions. For example, some infill sites may require some level of environmental remediation prior to development due to previous uses on the site. At times, existing conditions or issues may not be known at the outset and are discovered as project construction begins. These types of issues can increase project costs and level of complexity. However, the benefits of remediation and reuse of infill sites include a possible growth in the local tax base, more jobs, a cleaner environment, and support for community development and revitalization.

Beyond State requirements, local jurisdictions should consider policies that encourage infill development. According to a report published by the UC Berkeley Center for Law, Energy & the Environment (CLEE), best practices for incorporating infill development into land use elements include the following:

  • Identify the most appropriate infill types in the local context; 
  • Create a list of potential infill sites; 
  • Simplify development regulations to allow for flexibility in land reuse; 
  • Create design standards to protect existing community character; and, 
  • Incentivize lot consolidation and small lot development. 

The CLEE report in the Available Resources section above discusses policy recommendations for incorporating infill development, including sample general plan goals, policies, and implementation strategies, and provides examples from California communities. 

Relevant State Law

The State Legislature has prioritized infill development in recent years and has passed a number of bills that incentivize this type of development, most notably Senate Bill No. 35 (SB 35) (2017) and Senate Bill No. 10 (SB 10) (2021): 

Senate Bill No. 35 (SB 35) (2017) requires jurisdictions that have not made sufficient progress towards their RHNA allocations are required to use a streamlined, ministerial review process for affordable housing projects on urban infill sites, among other requirements.

Senate Bill No. 10 (SB 10) (2021) allows jurisdictions to adopt zoning regulations that would allow up to 10 dwelling units on any parcel located within a transit-rich area or urban infill site. Adoption of these zoning regulations is exempt from CEQA review.


League of California Cities. Streamlined Processing of Ministerial Projects Under SB 35.

County of Sacramento, Office of Planning and Environmental Review (PER). Senate Bill 35 Permit Streamlining Preliminary Eligibility Determination Application Form.

County of Sacramento PER. Affordable Housing Streamlined Approval Pursuant to Senate Bill 35 Information Sheet.

University of California Berkeley School of Law Williams, C. & Center for Law, Energy & the Environment. Integrating Infill Planning in California’s General Plans: A Policy Roadmap Based on Best-Practice Communities. 


City of Fresno. The City of Fresno has taken a proactive approach to infill development with its 2035 General Plan and subsequent adoption of the Infill Development Act by the City Council. Through its comprehensive development code update in 2015, the feasibility of infill development was increased citywide. The City has focused its infill development efforts on the Blackstone and Kings Canyon Transit Corridors and several residential and mixed-use projects have been constructed/approved in the area. Proactive planning has also led to multiple grant awards through the IIG program.

Funding Resources

Infill Infrastructure Grant Program (IIG). The Infill Infrastructure Grant Program is a competitive grant program intended to promote infill housing development by providing financial assistance for Capital Improvement Projects that are an integral part of, or necessary to facilitate the development of, a qualifying infill project or area. Eligible activities/costs include construction, rehabilitation, demolition, relocation, preservation, and acquisition of infrastructure. Within the San Joaquin Valley region, the following agencies have been awarded IIG funds: Housing Authority of the City of Fresno ($1.8M in 2019 and $1.16M in 2018) and City of Dinuba ($1.56M in 2018). More information can be found on HCD Infill Infrastructure Grant Program (IIG) Website.

California Transportation Commission. Solutions for Congested Corridors Program (SCCP) is a statewide, competitive program that provides funding to achieve a balanced set of transportation, environmental, and community access improvements to reduce congestion throughout the state. Projects must address how they support infill development to qualify.