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Infill Development

This page provides an overview of infill development for local governments in Washington State, including relevant statutes, useful resources, and examples of local infill plans and ordinances.


Communities across the country are increasingly recognizing that the spread out patterns of growth, which have shaped American communities for the past several decades, cannot be sustained. Problems of lengthy commutes, overextended public facilities and increased infrastructure costs, loss of farmlands, open space, and other valued community resources, and even reduced physical activity and community health are typically associated with such patterns. Instead, an increased emphasis on developing passed-over parcels within developed areas, and on maximizing use of existing public facilities is needed. Many Washington communities have adopted urban growth boundaries that restrict the amount of land outside of urban centers that is available for urban development. The reduced land supply has created new interest in infill development opportunities in central and suburban cities alike.

Infill development is the process of developing vacant or under-used parcels within existing urban areas that are already largely developed. Most communities have significant vacant land within city limits, which, for various reasons, has been passed over in the normal course of urbanization. Ideally, infill development involves more than the piecemeal development of individual lots. Instead, a successful infill development program should focus on the job of crafting complete, well-functioning neighborhoods. Successful infill development is characterized by overall residential densities high enough to support improved transportation choices as well as a wider variety of convenience services and amenities. It can return cultural, social, recreational and entertainment opportunities, gathering places, and vitality to older centers and neighborhoods. Attention to design of infill development is essential to ensure that the new development fits the existing context, and gains neighborhood acceptance. A cooperative partnership between government, the development community, financial institutions, non-profit organizations, neighborhood organizations and other resources is essential to achieve infill success. In the long view, the public and private costs of continuing to favor sprawl development patterns will far exceed the resources needed now to facilitate infill development. 

Relevant Statutes

  • Ch. 36.70A RCW - The Growth Management Act
  • RCW 43.21C.299 - Infill development - Categorical exemptions from chapter (SEPA)
  • Ch. 35.100 RCW - Downtown and neighborhood commercial districts (sales and use tax increment financing)


Articles, Reports, Briefs, and Fact Sheets

Barriers to Infill Development

If communities are to succeed in promoting infill development, they will need to recognize and overcome impediments to such development. Neighborhood opposition, financing challenges, inflexible building code and development regulations, lengthy permit processes, substandard infrastructure, difficult land assembly, site contamination and other conditions may need to be addressed to attract infill development.

Infill Development Programs, Strategies, and Tools

Infill Toolkits

  • Envision Utah, Envision Utah Toolboxes - Envision has created a series of still useful tools and models for implementing their vision including a redevelopment potential model, brownfields redevelopment toolbox, and quality growth tools including residential street design and walkable community design.
  • Florida Planning Toolbox: Infill and Redevelopment Tools - Very interesting set of tools and resources illustrated with examples
  • Quality Infill Recommendation and Tools, Idaho Smart Growth and Urban Land Institute, Idaho District Council, 01/2010 - Makes recommnedations for quality infill and surveyed successful programs from many communities to locate innovative tools for implementing recommendations
  • Tools for Civic Engagement, Sacramento Area Council of Governments - Useful educational videos and excellent photo simulations of phased infill developmnent to illustrate the potential to transform an area over time  

Washington Programs

  • Richland Infill Homeownership Program and Gap Assistance Program - Richland 2013 Annual Action Plan, pp. 8-10 -Program uses HUD HOME funds to purchase and rehabilitate vacant, dilapidated homes for resale.  Gap assistance program enables first-time homebuyers to purchase decent, affordable infill-housing by providing a gap assistance loan to supplement mortgage
  • Spokane Infill Housing Zoning Code Update Project - In addition to draft amendments, white papers and presentation materials, includes comprehensive plan infill policies and codes, such as the pocket residential development standards,and a nifty self-guided infill tour of local examples (under Project Materials and Resources)
  • Tumwater Sidewalk Infill Program - The city covers up to 80% of the cost of adjacent sidewalks for residential infill lots.

Programs in Other States 

  • Portland, OR Infill Design Program - This exceptionally useful webpage focuses on improving the design of multi-family and rowhouse development, especially those located in transit corridors and commercial centers. It includes an very useful guidebook/toolkit containing a wide range of strategies and prototype designs that allow fast-track approval. The website also provides examples from a courtyard housing design competition and has links to many interesting reports, presentation materials, and other documents
  • Sacramento, CA Infill Program with link to City of Sacramento Infill Strategy, 05/14/2002 - Coordinated strategy still guides city infill efforts, although slowed by economic downturn. Strategy emphasizes incentives and project assistance focused on target infill areas iuncluding fee waivers and flexible standards. Also see City Sponsored Infill Housing Plans - Pre-approved house plans to facilitate infill development.



  • Auburn Municipal Code Ch. 18.25 - Infill Residential Development Standards
  • Bellingham
  • Seattle Municipal Code Ch. 23.43 - Residential Small Lot Zone
  • Sultan Unified Development Code Ch. 16.24 - Standards for Infill Development in Residential Areas - Simple small city example
  • Tacoma Municipal Code Ch. 13.06 - Supplemental provisions for single family residential development
  • Vancouver Municipal Code Ch. 20.920 - Infill Development Standards

Other States

  • Alexandria Zoning Code, Article VII Sec. 7-2500 - Infill regulations for single- and two-family residential zones
  • Austin, TX
  • Maryland Ch. V - Model Infill Ordinance, from Managing Maryland's Growth: Models and Guidelines for Infill Development, Maryland Department of Planning
  • Portland, OR
    • Zoning Code Ch. 33.405 - Alternative Design Density Overlay Zone
    • Zoning Code Sec. 33.110.240 - Alternative Development Options - Duplex on corner lots and other potentially useful infill options

Incentives to Facilitate Infill Development

Many communities are using incentives to make infill more attractive and affordable to developers and to address impediments to infill development such as those described above.

  • Incentives for Infill and Redevelopment, Florida Planning Toolbox, Center for Urban and Environmental Solutions, Florida Atlantic University - Describes use of transfer of development rights, leveraging publicly-owned real estate, land banking and others as infill incentives.  Scroll to page 112
  • Infill Incentives, Policy Link - Provides a helpful overview, descriptions of a variety of infill incentive options, and several examples, such as the Tacoma, WA multi-family tax exemption
  • Infill Incentives Recommended by the General Advisory Panel, Lafayette Consolidated Government Planning Division, LA, 01/2008 – Actions local governments can take to make infill development more attractive to developers and potential residents. (Ideas borrowed from an MRSC publication!)  
  • Miami Dade County, FL Infill Housing Initiative Guidelines, revised 11/14/2012, and Infill Housing Developer Requirements – Miami-Dade County has designated infill target areas and established a program that provides incentives to encourage developers to build affordable housing, and redevelop vacant, dilapidated or abandoned properties in urban neighborhoods. Incentives include release from county liens, impact fee refunds, low interest loans, an expedited building permit process, and other incentives  
  • Riverside, CA Residential Infill Incentive Program - See especially Fee Adjustments and Cost Avoidances
  • San Diego, CA Expedite Program for Affordable/in-Fill Housing & Sustainable Buildings, Information Bulletin No. 538, 01/2012 - Allows expedited permit processing for affordable infill housing developments that have 10 or more proposed units and are located within designated urbanized areas
  • Tucson, AZ Land Use Code, Art. 2, Div. 8, Sec. 2.8.12 - After several years of practical experience with infill incentives,this revised code provides an option to modify development regulations by up to 25% (and in some cases, more) within two downtown infill incentive overlay districts, as incentives to infill development. Design criteria particularly address transitions between infill and existing development, and mitigation of tall buildings.

Funding Resources and Costs

Programs to stimulate infill development and the infill development itself, may require a creative combination of funding sources, and public-private partnerships.

  • Community Development Block Grant, Pasco, WA - Pasco partners with the Tri-Cities Consortium to provide affordable housing opportunities for low and moderate income people and opportunities for downpayment assistance, infill assistance, and rehabilitation help.
  • Seminar 4: Creative Financial Tools and Techniques for Infill, Institute of Urban and Regional Development, University of California, Berkeley, 04/28/2011 - Online seminar focuses on regional and local financial strategies that have been successfully used to support the installation of transit infrastructure, street and pedestrian improvements, utilities, and open-space facilities essential for successful infill development.
  • Strategies for Fiscally Sustainable Infill Housing, University of California Center for Community Innovation, Greenbelt Alliance, 09/2011 - Helpful discussion of the costs and revenues associated with infill development. Provides a primer on fiscally sustainable infill, and describes funding mechanisms such as value capture, special assessment districts, and impact fees
  • Washington Complete Streets and Main Street Highways Case Study Resource, WA-RD 780.1, Washington Department of Transportation (WSDOT), 11/2011 - See especially pp. 48-50 concerning competitive grant program, which provides funds for transportation improvements (mainstreets and certain city streets) that support economic vitality, accommodate infill and connect housing and employment.
  • 2010 Inventory of TOD Programs: A National Review of State, Regional, and Local Programs that Fund Transit-Oriented Development Plans and Projects, Reconnecting America, 01/2011 - Provides interesting examples of state, regional and local programs to fund planning, implementation and property acquisition for infill development that doubles as transit-oriented development

Design for Infill Compatibility

Infill development design guidelines are useful tools for ensuring that the new development fits the existing context, and gains neighborhood acceptance. It is not uncommon for existing residents to resist new development within a neighborhood, particularly true when motivated by past bad experiences with new development, which failed to fit existing neighborhood character. Design guidelines in general can help assure more aesthetic development. Design guidelines that focus on infill development can guide the process of integrating new development carefully into the existing neighborhood fabric with respect to block patterns, scale, building features, landscaping, and other characteristics of the neighborhood.

  • Design Review, MRSC - Includes many examples of Washington and out-of-state design guidelines generally intended to assure that new development is compatible with neighboring existing development. Includes guidelines for historic districts, downtowns, transportation corridors, and different types of residential neighborhoods
  • Heart of Knoxville Infill Housing Design Guidelines, Knox County Metropolitan Planning Commission, TN - Nicely formatted, user-friendly guidelines. Includes checklist for infill appropriateness.
  • Overland, KS Infill and Redevelopment Design Guidelines, 2004 document posted 01/20/2011 - Comprehensive guidelines cover single-family, multi-family and commercial infill development, including a section on hotels and motels.
  • Portland, OR
    • Infill Design Project - Very useful webpage includes infill design toolkit, housing prototypes, courtyard housing design competition results, and other infill housing types
    • Infill Design Strategies: Portland's Experience, Bill Cunningham, Portland Bureau of Planning & Sustainability presentation to Makeover Montgomery (MD) 2011 - Excellent PowerPoint clearly illustrating Portland's infill design approaches and tools. Emphasis on medium-density infill in established neighborhoods. Includes many examples illustrating facilitative regulatory solutions, non-regulatory strategies such as pre-approved housing prototypes, and design competition entries.
  • Residential Infill - Includes link to Residential Infill Guidelines: A Manual of Planning and Design Guidelines for Residential Infill in Mature Neighborhoods, city of Edmonton, BC, 09/2009 - Comprehensive guidelines for all forms of infill (accessory units, small lot, duplexes, row housing…) in small-scale, medium-scale, and large-scale development situations

Special Types of Infill Housing and Supporting Services

Infill development may be very small in scale, such as a single family house on a vacant lot within a developed block. It can also occur on a much larger scale, such as an entire block or even the redevelopment of many acres as in the case of the land area left behind when an airport within a city is relocated. In this case, an entire new neighborhood may be created, in the midst of other existing neighborhoods. Different types of infill development may be appropriate depending on the surrounding context and a community's goals for future growth. This section presents some different infill development options and provides some accompanying models, prototypes and design tools that can be used to assure good fit or transition with surrounding development. At the same time, new infill development can often add some benefit that may have been missing from a neighborhood such as some increase in density to help support more frequent transit service, or adding a corner convenience store or green space.

Illustrative Examples and Case Studies

This section provides illustrative examples of successful infill developments for various contexts. Case studies can offer ideas and a better understanding of what is possible, while also providing important lessons learned.

  • Boulder, CO Wild Sage Housing, Urban Land Institute, posted 2006 - Case study: a 34-unit, mixed-income, environmentally friendly cohousing project, is one of several small communities being developed in a new urbanist, sustainable, and affordable neighborhood rising from the site of a former drive-in movie theater in Boulder, CO.
  • Calgary, Alberta, CA Garrison Woods, Urban Land Institute, posted 2008 - Case study: first phase of a master-planned community involving redevelopment of a decommissioned military base. The traditional neighborhood development-style infill project is located ten minutes from downtown.
  • Denver, CO Lowry Neighborhood Project, Smart Growth Online, posted 05/29/2006 - Case study: large scale infill redevelopment of Lowry Air Force Base designed to blend with surrounding neighborhoods.
  • Greensboro, NC Southside Neighborhood, Smart Growth Online, posted 10/03/2005 - Case study: ten acre mixed use, infill project created a complete neighborhood with services, amenities, and a neighborhood common to become a market success. Still a useful example.
  • Murray, UT Inverness Square, Urban Land Institute, posted 2008 - Case study: 119 townhouse infill units developed as workforce housing on a former brownfield site.
  • Portland, OR Belmont Dairy, Smart Growth Online, posted 10/03/2005 - Case study: Award-winning mixed use, transit-oriented, urban infill development transforms former dairy with loft apartments and rowhouses. Design emphasizes the site's historic connection to the neighborhood and is still a great model.
  • Seattle, WA The Boulders, Urban Land Institute, posted 2006 - Case study: a cluster of nine single-family homes built around a hillside garden court located on an infill site ten minutes from downtown Seattle in the Greenlake neighborhood. Designed to appeal to environmentally informed, relatively affluent buyer.

Infill Studies

Many communities in Washington and other states are analyzing the capacity of potential infill sites to accommodate new growth as and alternative to sprawl development. Washington State has established a Buildable Lands program that requires certain high growth counties and cities to monitor land supply within urban growth areas. These jurisdictions analyze vacant, underutilized and partially used land to estimate land supply available to accommodate anticipated growth and various land use needs within the UGA.

Infill Study Guidance

Infill Studies and Capacity Analysis

  • The Consequences of Infill Development in Existing Neighborhoods in Treasure Valley: A Study and Conclusions, and report presentation, Idaho Smart Growth and Urban Land Institute, 2008 - Highly readable report investigates traffic impact, quality of design and other potential impacts. Includes case study and residential survey information.
  • Envision Utah Redevelopment Potential Model (RPM), Version 1, 06/2007 plus Appendix added 06/2011 - This pro forma model estimates revenues and costs in a potential redevelopment area where development is maximized under existing zoning and building codes. The end result is an estimate of the redevelopment potential for a study area, and a better understanding of the impact of zoning controls on potential return on investment.
  • The Future of Infill Housing in California: Opportunities, Potential, Feasibility and Demand, 09/2005 - Describes a new tool, the California Infill Parcel Locator, and provides an analysis of the opportunities and limitations of expanding infill housing development potential. Although the state no longer runs the tool, the study information and tool concept are still useful.
  • Minneapolis, MN Land Capacity Analysis, 06/2010 - Clearly written description of the analysis of current land supply and the forecast of land demand based on employment trends, and population and housing trends. Note that in this document, the term "infill" refers to surplus land within a developed parcel large enough to accommodate additional development.
  • Portland, OR Buildable Lands Inventory - Summary of Residential Capacity, City of Portland Development Land Capacity Analysis, 05/2011 - Summary of Portland's analysis of land capacity from infill and redevelopment, and description of Portland's model to project development capacity and develop scenarios describing how growth might occur in the future
  • Residential Construction in America's Metropolitan Regions, U.S. Environmental Protection Agency, 01/2010 - Documents dramatic shift in infill and redevelopment toward central cities and suburban cores
  • San Mateo County, CA Transit-Oriented Development Opportunity Study, Final Report, 07/2007 - Transit Orient Development is one type of infill development. This study contains very useful insights about addressing factors that can facilitate both small scale infill parcel development for parcels near stations and land assembly for larger infill development near TOD.
  • Vacant Properties: The True Costs to Communities, National Vacant Properties Campaign, 2005 - Summarizes research on the costs vacant and abandoned properties impose upon communities and highlights local programs successfully recapturing the value in these properties. Still highly relevant in era of foreclosures.

Washington Studies

  • Washington State Buildable Lands Program: 2007 Evaluation Report - A Summary of Findings, Washington Department of Community Trade and Economic Development, 08/2008 - Describes Washington State buildable lands reporting program and summarizes countywide results of participating counties
  • 2007 King County Buildable Lands Report - King County is one of six Washington counties (and their cities) that must monitor and determine the amount of land suitable for urban development, and evaluate the capacity for growth, based upon measurement of five years of actual development activity. The counties must report to the State every five years.
  • Snohomish County 2012 Buildable Lands Project and 2007 Buildable Lands Report - These documents describe the basic process for next buildable lands analysis and report required by the state.

Infill vs. Greenfield Infrastructure Costs

Last Modified: January 06, 2022