California’s housing affordability crisis has rightly received a great deal of attention by state lawmakers, the press, academics, and ordinary Californians. Important questions raised in this discussion are: What laws or regulations might impede housing construction in high-cost areas? What solutions might help reduce those barriers with a minimum impact on other important values, such as environmental protection, public participation, and equitable treatment of low-income communities of color? More specifically, does state environmental law (the California Environmental Quality Act, CEQA), or local land-use regulations, constrain housing development? To help answer that last question, we collected data on all residential development projects (of more than five units) over a three-year period in five Bay Area cities (San Francisco, Oakland, San Jose, Redwood City, and Palo Alto). We analyzed the law applicable to these residential development projects, including the local zoning ordinances, and interviewed important actors in the residential development process in each of these five cities. We found that these local governments are imposing discretionary review processes on all residential development projects of five or more units within their borders. That means even if these developments comply with the underlying zoning code, they require additional scrutiny from the local government before obtaining a building permit. This triggers CEQA review of these projects. In other words, what drives whether and how environmental review occurs for residential projects is local land-use law. Our data shows that in many cases, these cities appear to impose redundant or multiple layers of discretionary review on projects. We also found that the processes by which local governments review residential development projects under their zoning ordinances and under CEQA varies from city to city. As a result, developers seeking to construct residential projects often must learn to navigate very different and complicated land-use systems, even if they work in the same region. This appears to particularly burden smaller development projects. Our data also shows that these cities rely on streamlined CEQA procedures for the majority of their residential projects, including many large projects. The effectiveness, however, of those streamlined procedures in terms of reducing timeframes for project approval varies greatly from city to city, indicating that a range of non-legal factors (such as practices in planning departments, or the amount of resources dedicated to planning) may impact development timelines. Finally, our own research process also revealed that the kind of project level data that we collected, while essential to crafting effective solutions to the California housing crisis, is not easily available. We therefore recommend that the legislature develop a consistent and uniform data reporting program for this data, which will benefit policymakers, developers, and the public as a whole.