More Cities Legalizing 'Granny Flats'

Accessory Dwelling Units continue to gain steam as one approach for increasing affordability, but experts caution that housing affordability requires broader solutions.

2 minute read

January 15, 2021, 6:00 AM PST

By Diana Ionescu @aworkoffiction


Residential Development

Rungtiwa P / Shutterstock

Cities and states across the country are realizing the potential of legalized Accessory Dwelling Units (ADUs) as an inexpensive way to increase density and available housing units without drastically changing a neighborhood's character. According to Kol Peterson, author of Backdoor Revolution: The Definitive Guide to ADU Development, "there has been a dramatic uptick in ADU regulatory relaxation over the last few years." In a piece for the Washington Post, Haisten Willis assesses the benefits of ADU construction, which is experiencing a resurgence, particularly in high-cost, low-density neighborhoods on the West Coast.

California and Oregon have passed statewide legislation legalizing ADUs, and Chicago is implementing a pilot program to test the concept. Between 2016 and 2019, ADU permits in California jumped from 1,269 to 14,702, signaling a pent-up demand for "granny flats." Los Angeles, which issued 80 ADU permits in 2016, issued 6,747 in 2019.

The ADU can be an ideal housing type for seniors who want to live near their family and provides an unobtrusive way to increase available units, but advocates admit that "the devil is in the details" and more oversight is required to ensure ADU landlords can navigate the process and maintain adequate living conditions. "It still doesn’t absolve the city from the protections they need to keep for renters," says organizer Ebonée Green. Homeowners who want to build ADUs don't always know how to manage contractors or get permits, and banks, unfamiliar with the construction type, have so far been reluctant to issue loans for ADU projects.

While the growth in ADU construction is encouraging, experts warn that legalizing ADUs is only "a small tool in the box," not a broad solution to housing affordability issues.

Thursday, January 7, 2021 in The Washington Post

portrait of professional woman

I love the variety of courses, many practical, and all richly illustrated. They have inspired many ideas that I've applied in practice, and in my own teaching. Mary G., Urban Planner

I love the variety of courses, many practical, and all richly illustrated. They have inspired many ideas that I've applied in practice, and in my own teaching.

Mary G., Urban Planner

Cover CM Credits, Earn Certificates, Push Your Career Forward

Logo for Planetizen Federal Action Tracker with black and white image of U.S. Capitol with water ripple overlay.

Planetizen Federal Action Tracker

A weekly monitor of how Trump’s orders and actions are impacting planners and planning in America.

June 11, 2025 - Diana Ionescu

Rendering of Shirley Chisholm Village four-story housing development with person biking in front.

San Francisco's School District Spent $105M To Build Affordable Housing for Teachers — And That's Just the Beginning

SFUSD joins a growing list of school districts using their land holdings to address housing affordability challenges faced by their own employees.

June 8, 2025 - Fast Company

Yellow single-seat Japanese electric vehicle drivign down road.

The Tiny, Adorable $7,000 Car Turning Japan Onto EVs

The single seat Mibot charges from a regular plug as quickly as an iPad, and is about half the price of an average EV.

June 6, 2025 - PC Magazine

People riding bicycles on separated bike trail.

With Protected Lanes, 460% More People Commute by Bike

For those needing more ammo, more data proving what we already knew is here.

2 hours ago - UNM News

Bird's eye view of half-circle suburban street with large homes.

In More Metros Than You’d Think, Suburbs are Now More Expensive Than the City

If you're moving to the burbs to save on square footage, data shows you should think again.

4 hours ago - Investopedia

Color-coded map of labor & delivery departments and losses in United States.

The States Losing Rural Delivery Rooms at an Alarming Pace

In some states, as few as 9% of rural hospitals still deliver babies. As a result, rising pre-term births, no adequate pre-term care and "harrowing" close calls are a growing reality.

June 15 - Maine Morning Star