Recent record-setting droughts, climate change, and population growth have strengthened the urgency of a diversified water portfolio in California. While desalination has historically been a small contributor to California’s water supply, drought conditions and water shortages have spurred cities to build desalination plants along the coast. Thus, desalination will likely play an increasing role in meeting growing water demand in the State, in conjunction with other sources including brackish desalination, recycled water, and stormwater. However, desalination remains economically and environmentally costly, particularly for low-income, minority communities. Thus, this paper seeks to understand the factors behind whether a desalination project is approved or denied, using four recent projects in California as case studies: Carlsbad (in operation since 2015), Huntington Beach (denied May 2022), Doheny (approved October 2022), and Marina (approved November 2022). Analyzing four factors—permitting process, environmental impact, cost on the local community, and dependence on desalination—these case studies highlight the importance of using desalination as a last resort option, mitigating a project’s impacts on marine life and the environment, and involving the local community in the decision-making process. Part I provides an overview of desalination and its controversial nature, and briefly traces the role that drought has played in spurring desalination projects along the coast. Part II provides an overview of key federal and state laws that regulate desalination projects. Part IV analyzes the factors that affect whether a desalination project is approved in California, using four recent projects, described in Part III, as case studies. Part V outlines recommendations and best practices that California can adopt as the State continues to develop desalination projects. Part VI concludes.