Zoning for Accessory Housing

Zoning Practice — July 2012

By Thomas Daniels


ZP subscriber
List Price
Sign In & Download

Not a member but want to buy a copy? You'll need to create a free My APA account to purchase. Create account

Accessory housing may either be a detached dwelling unit with full services — bath, sleeping quarters, and kitchen — or an autonomous apartment attached to a house. Whether attached or detached, accessory housing can increase residential densities and encourage walkability. However, many older zoning ordinances present major obstacles to the creation of accessory dwelling units (ADUs).

Efforts to retrofit suburbs and encourage infill in cities have often focused on large projects such as redeveloping dead malls and multistory mixed use commercial and residential buildings. But financing for these projects is less available since the 2007 downturn in the real estate market. One less conspicuous way to provide more rental units is through an accessory housing ordinance in single-family residential districts.

This issue of Zoning Practice outlines a strategy for incorporating accessory housing standards into local zoning codes and highlights a few examples of communities where this approach has been effective.


Page Count
Date Published
July 1, 2012
Adobe PDF
American Planning Association

About the Author

Thomas Daniels
Professor Tom Daniels teaches Land Use Planning and Environmental Planning at the University of Pennsylvania. He is the author of The Environmental Planning Handbook (APA secnd edition, 2014) and co-author of The Small Town Planning Handbook (APA third edition 2007). Tom has written extensively on climate change and is part of a team studying solar development on farmland in Pennsylvania. Tom has given several presentations at the American Planning Association Conference.