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Symbium Opens Service for Analyzing Zoning, Building Codes

The San Francisco company hopes to make a dent in California’s housing crisis by giving homeowners and developers an interactive mapping tool to show them if and how they can build an accessory dwelling unit.

Symbium accessory dwelling unit screenshot
With a little wind in its sails from recent investments, a San Francisco startup called Symbium has built the city planning codes of eight California municipalities into an interactive map to help homeowners quickly answer questions about their building projects.

The company launched its “Build+” subscription service for city staff and private developers on March 1, a more versatile iteration of the company’s “Build” platform for the general public. As with Build, Symbium designed Build+ with a focus on accessory dwelling units — smaller, secondary units on the same parcel as a larger one — but its capacity to analyze other kinds of structures and entertain hypothetical scenarios could have broader implications for the future.

Prior to co-founding Symbium, CEO Leila Banijamali was an enterprise technology lawyer who had noticed how cumbersome and difficult it was for most people to interact with laws and regulations. Whenever they wanted to build something, residents and companies alike had to navigate a labyrinth of bureaucracy, paperwork and constantly changing municipal codes that took so much time and money that some found it prohibitive. She said it’s also typical that talking to different planners on different days will yield different responses to the same question.

Banijamali set out to develop a new platform based on the concept of “computational law,” which essentially means translating laws and regulations into computer code so that software can analyze them like any other data. What her team created at Stanford University, called Complaw, became the underlying technology for Build and Build+, Symbium’s products that visualize planning and zoning codes so that city staff, architects, builders and homeowners can work on their projects with less consultation of massive code books or the local planning office.

“What we learned, when we were shadowing the planners in all of our research prior to launch, is that the actual bottleneck is the rules — navigating them, understanding them and figuring out how they apply to your particular project,” she said. “We’re taking that away so that now, you’re changing multiple months and iterations to just a few clicks, to instantly find out, what can I do? And you can do that from your home just by going to Now you can understand if an ADU is allowed, and if so, the detailed development standards and processes that apply.”

To date, Symbium has been building its Google Maps-like portals for six local governments in the Bay Area — San Francisco, San Jose, Pacifica, Orinda, Redwood City and San Mateo County — and two in Southern California — Los Angeles and Fontana.

Banijamali likened Build and Build+ to TurboTax, which has tax laws built into it so the user gets instant feedback as they type and use the program — Build being the publicly available version, and Build+ being a subscription-based one. They both allow a user to type in an address to see property information like zoning, lot area, number of units and what’s possible on that property. A user could then browse different possible designs for ADUs, supplied to Symbium by a handful of developer partners they’re working with so far, and add it to their parcel to see who the developer is, some materials and cost estimates, and a description of the process it would take to build in real life.

When the user manipulates the image model in a way that that city’s planning code would not allow, the model turns red and explains why. Build also generates a report showing what steps the user went through and what the next ones are, which the user could print out and take to the city planning department so an official can quickly verify the work.

Banijamali said the system has even identified inconsistencies or contradictions in a planning code that city staff didn’t know about. But she was adamant the software doesn’t replace planners, as it’s not suited for design-discretionary rules that require expertise.

“The response we’ve gotten from planners at the counter is, they want this tool, because most of the questions they’re being asked at the counter are not things they want to be spending their time on: Can I build this? How much does it cost? What form do I fill?” she said. “Planners want to be doing what they’re trained to do, which is the discretionary design review stuff.”

An innovation with Build+, launched this week, is the program’s ability to entertain hypothetical scenarios, like the potential impacts of a specific change in public policy or population. The company focused on ADUs to start with because of the possibility that those will play a valuable role in addressing California’s housing crisis, and Product Manager Phi Phan said Build+ was designed with this issue in mind.

“A lot of cities are worried about a lack of housing, and they might say, ‘Hey, this area is next to transit and could really benefit from more housing. Let’s see how our current policy builds up those areas,’” he said. “Just this year, the ADU laws throughout California changed. If they were using a tool like Build+ in advance of that, they could have seen visually and through statistics how those changes and regulations would impact ADU capacity, and in what area.”

Phan said Build+ has also piqued the interest of developers who could use it to identify the neighborhoods in which their advertising would be most effective.

“We have some developers that have, say, a 15-foot by 40-foot ADU, and they want to do some heavy marketing. They want to know where to target their efforts,” he said. “They could just go into Build+, search by 15-foot by 40-foot ADU, put in some other factors like income and age, and target exactly who they want to target.”

Banijamali said the plan is to cover California this year and then expand beyond it, particularly with business zoning, but in the longer term, Complaw might be used for more than zoning codes. Interested in streamlining insurance, mortgages or any number of processes that can be inscrutable to the average person, she said her goal is to make sure more people have access to the law, understand what can be done and don’t have to consult staff and experts as often.

“My vision for the future is that computational law will be embedded in every experience we have with the law. I want to fundamentally disrupt how people interact with laws, not just in planning, but in every vertical that is highly regulated,” she said. “I want the laws themselves to be brought closer to the point of human experience, so that you interact with them at the point that you actually need them. When you’re driving your Tesla across the border, the car should tell you exactly what the speed limit is, and that you shouldn’t be smoking your marijuana anymore because it’s not legal in this state.”

Andrew Westrope is managing editor of the Center for Digital Education. Before that, he was a staff writer for Government Technology, and previously was a reporter and editor at community newspapers. He has a bachelor’s degree in physiology from Michigan State University and lives in Northern California.