Sweetwater Spectrum Community

Sonoma, California

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By Marsha Maytum

The following case study is an excerpt from Practice with Purpose: A Guide to Mission Driven Design (ORO Editions, 2022), by LEDDY MAYTUM STACY ARCHTECTS, a book that is about designing buildings beyond their property lines to address some of society’s most urgent challenges: the climate emergency, racial and ethnic injustice, chronic homelessness, educational crises, and the preservation of the embodied carbon and culture of existing buildings. It features the award-winning work of LEDDY MAYTUM STACY ARCHTECTS (LMSA), a national leader in the design of environments that promote social justice and advance urgent climate action.

Also read William Leddy’s Terrain.org guest editorial, “Architecture is a Social Justice Issue,” excerpted from Practice with Purpose.

Reprinted with permission of the author and publisher.

Sweetwater Spectrum Community evening
Low walls at Sweetwater Spectrum Community provide separation from more public areas yet retain opportunity for social interaction.
Photo by Tim Griffith.
The Sweetwater Spectrum Community is a national model of supportive housing for adults living with autism spectrum disorder (ASD) and related disabilities. Created to address a growing national housing crisis for adults with ASD, this community for 16 residents in Sonoma, California integrates autism spectrum-specific design, universal design, and sustainable design strategies.

I lead our monthly public tours for the past six years, and seeing Sweetwater as a model gives countless other parents (from around the country and the globe) hope that they too can build a version of Sweetwater in their community, and that their loved ones might have an option beside spending their lifetimes in family homes. 
– Kory Stradinger, Executive Director, Sweetwater Spectrum

Sweetwater Spectrum Community site map
Image courtesy LMSA.

In 2009, a group of families, autism professionals, and community leaders founded the nonprofit Sweetwater Spectrum organization to meet an extraordinary need—appropriate, high-quality, long-term housing for adults with autism. ASD is the fastest-growing developmental disability in the United States: in 2000 the Centers for Disease Control and Prevention (CDC) estimated that autism effected one in 150 children in the US. By 2021, the CDC reported a prevalence of one in 44 children—an increase of 241 percent. In this decade alone as many as 500,000 children living with ASD will reach adulthood, yet few residential options exist for them. To help address this impending housing crisis, Sweetwater Spectrum was formed to create a model cohousing project that could be replicated nationwide.

Sweetwater Spectrum Community
Outdoor spaces offer residents options for contemplative connection to nature as well as group activities.
Photo by Marion Brenner.

The project goal was to create a healthy, pragmatic, and nurturing environment for adults on the full spectrum of autism and to support all financial capabilities. The model provides permanent homes for the residents throughout their lives with supportive services tailored to and evolving with the needs of the individual residents at each phase of their lives.

The site for the first community was an undeveloped 2.8-acre midblock parcel located near Sonoma’s historic town square. The program includes four four-bedroom homes for 16 residents and their support staff; a small community center with exercise/activity spaces and teaching kitchen; a large therapy pool and spas; and an urban farm, orchard, and greenhouse that doubles as a land bank for possible future community expansion.

Sweetwater Spectrum Community Concept and Plan Diagram
Image courtesy LMSA.

The project was informed by the latest research into the environmental requirements of the growing ASD population. This included Sherry Ahrentzen and Kimberly Steele’s report Advancing Full Spectrum Housing: Designing for Adults with Autism Spectrum Disorders, which helped guide the project team in the design process. Following evidence-based design goals, spaces are designed to reduce sensory stimulation (ambient sound, visual patterns, odors, etc.) and to create a simple, predictable domestic environment. Safety and security are paramount, and healthy, durable materials are utilized throughout. Individuals may customize their personal living spaces to accommodate their preferences and particular needs.

Sweetwater Spectrum Community
Photo by Marion Brenner.

Major design strategies included providing a straightforward and consistent spatial organization with clearly defined transition thresholds between public, semipublic, semiprivate, and private spaces; establishing a layered or “nested” arrangement on the site from the scale of the individual to the scale of the community; integrating places to preview social activities at the periphery without necessarily joining in, as well as places of retreat for quiet and calm; designing all four homes similarly so that residents feel comfortable visiting their neighbors; reducing sensory stimulation and providing a serene environment for a wide variety of resident needs; and promoting healthy environments with practical sustainable design strategies.

Sweetwater Spectrum Community
Photo by Tim Griffith.

The design of this unique community demonstrates Sweetwater Spectrum’s founding principles and achieves its mission to provide adults with autism and other developmental disabilities an innovative, supportive residential community that challenges individuals to reach their potential. The project is a model that is being replicated in a variety of locations and scales nationwide.

Sustainability at Sweetwater Spectrum Community.
Image courtesy LMSA.

Integrated Universal and Sustainable Design

People living with ASD present a wide spectrum of cognitive and physical abilities, ranging from high-functioning individuals to those who have heightened hyper- and hypo sensitivities to environmental stimuli or physical, behavioral, and/or cognitive issues that require full-time assistance. Sweetwater Spectrum Community welcomes people of all abilities with simple universal design strategies that provide generous accommodation and equal access for all ages and abilities. As a long-term housing solution, the design integrates flexibility, accessibility, and adaptability to the specific needs of the residents as they age in place. Building materials and systems were selected to promote healthy indoor air quality and to provide acoustically controlled, serene spaces. Since ceiling fans can be a negative stimulus to people with ASD who have motion and pattern sensitivity, a radiant slab heating and cooling system was used and augmented with a low-velocity ventilation system. Energy-efficient appliances were installed, including induction cooktops which also provide greater safety to the residents. Photovoltaic panels and solar hot water collectors were incorporated on all buildings to provide renewable energy and reduce long-term operating costs. Designed to U.S. Green Building Council LEED Gold standards, the project is also a Pacific Gas and Electric Company Zero Net Energy Pilot Project, designed to produce on site all the energy required to operate the buildings annually.

Sweetwater Spectrum Community
Photo by Tim Griffith.

Design for Aging in Place

In the U.S., a majority of young adults with ASD live with their families. A report by the A. J. Drexel Autism Institute found that 87 percent of adults with autism lived with their parents during their early 20s, compared to 21 percent of the general population. Approximately one in four were socially isolated, with limited or nonexistent support systems outside their family. The overwhelming question parents of children with ASD ask is, “What will happen to my child when I can no longer care for them?”

Sweetwater Residents
“She made friends for the first time in her life. When she was growing up, social skills was a huge focus for us. She never actually built a relationship that we see in the friendships she has here,” says a parent of a Sweetwater resident.
Photo courtesy Sweetwater Spectrum.

Limited residential options are available outside the family home for adults living with ASD. These include large institutions or group homes, which are typically adapted single-family residences that rely heavily upon the stability of individual caregivers. If a resident’s care requirements change, the resident must move to another situation, causing disruption and stress to them and their family. The Sweetwater Spectrum Community provides a new option for families—a long-term permanent home where residents may remain for their lifetimes where their care can evolve over time without disrupting their living situation. The four houses at Sweetwater have simple, matching layouts that lend themselves to moving residents from one house to another with minimal disruption as their age, needs, and social contexts develop. This new housing model provides greater security and comfort for the family that their child will be cared for in a supportive home and community after they are gone.

Sweetwater Spectrum Community
Photo by Marion Brenner.

Community Inclusion

The surrounding city of Sonoma warmly welcomed the Sweetwater Spectrum Community and its residents from the start, supporting the project from the initial design review, and helping to pave the way for swift project approvals. Since completion, the interconnection between residents and the town has continued to grow beneficially in both directions. The site’s location within close walking and biking distance to downtown Sonoma and its historic town square helps to enable a key component of the Sweetwater Spectrum model, an enrichment program that fosters both individual choice and community engagement to provide a “life with purpose.” Residents have attended classes at a local junior college, worked in small local businesses, and participated in local choirs and orchestras. The Sweetwater farm hosts a seasonal farm stand where residents sell produce they’ve grown to the public. Conversely, members of the community volunteer on site and at the farm and participate in various events on site throughout the year. Parents of Sweetwater residents report that their children are fully integrated into the community of Sonoma. As one parent observed when walking downtown with their daughter, “Everyone we passed waved and said hello. We knew that she had been out and getting to know people in town.”

Sweetwater Spectrum Community farm
The farm connects residents to nature, healthy eating, and community interaction. Sweetwater residents and volunteers sell their produce to the Sonoma community.
Photo courtesy Sweetwater Spectrum.

Designing a Replicable Housing Model

An important part of Sweetwater Spectrum’s vision was to create a replicable model of supportive cohousing for adults with ASD and related disabilities. Its mission was to offer “choice to its residents with individual, customized. and flexible programs, supporting life skills training, continuing education, gardening, art/music, exercise, and healthy lifestyles.”

There has been intense interest in the Sweetwater Spectrum Community from individuals and organizations around the country and abroad. Building upon its years of experience as well as post-occupancy evaluations and research studies on the process and outcomes at the model project, Sweetwater Spectrum launched a Creating Housing program. Through tours, symposia, presentations, outreach, an online toolkit, and consulting services, the nonprofit organization aims to share its insights with others working to address the housing needs for this population. The “Housing Toolkit” is assembled from materials emerging from their experience at Sweetwater Spectrum Community and from their Replication Symposia. It is available for free to help teams at any stage of development to address the ASD housing challenge. Since launching the new Creating Housing program in early 2021, Sweetwater has seen more than 1,100 new users representing 44 states and more than ten countries. More than 80 users have accessed the “Replication Starter Kit,” and many more have participated in the Replication Symposium.

We researched over 20 communities, and we found the Sweetwater model to be “best-in-class” and proven with over eight years of successful operating experience. The information their team is able to share and their real world “lessons learned” have been invaluable for us. 
– Ara Bagdasarian, Solon Community Living


Marsha MaytumMarsha Maytum FAIA, LEED AP, is a founding principal at LEDDY MAYTUM STACY ARCHITECTS (LMSA) in San Francisco, winner of the 2017 National AIA Architecture Firm Award. Marsha has focused her career on community, cultural, and socially responsible projects that promote sustainable design, including the creation of new buildings, rehabilitation of historic buildings, and adaptive reuse of existing structures. LMSA has received over 175 regional, national, and international design awards, including 12 AIA COTE Top Ten projects. Marsha is a frequently invited juror and critic and has lectured nationally on the topics of sustainable design and adaptive reuse. She has served on the National AIA Committee on the Environment Advisory Group, and as its 2019 Chair. Marsha has been a visiting professor at the University of Oregon, University of California, Berkeley, and California College of the Arts. 

Read William Leddy’s Terrain.org guest editorial, “Architecture is a Social Justice Issue,” also excerpted from Practice with Purpose.

Header photo, Sweetwater Spectrum Community, by Marion Brenner.

Terrain.org is the world’s first online journal of place, publishing a rich mix of literature, art, commentary, and design since 1998.