Effects of Historic San Francisco Redlining on Rat Complaints Distribution and Occurrence
Keira Denlinger
Department of Psychology
Faculty Supervisor: Robert Boria
Rapid urbanization is one of the key ways humans are forever altering the global landscape. Human commensal rodents, in particular black and brown rats, pose a great risk to human health and community infrastructure. We examine whether redlining, a racially discriminatory housing policy implemented in the 1930s, is associated with present-day rat population density in San Francisco, California. Using San Francisco’s 311 database, we obtained rat complaints and mapped them over San Francisco’s current districts and with a map of 1930’s redlined districts to find correlations between this historic data and the instance of rat complaints. Our analyses indicate an overall increase in rat complaints over the last 15 years from 51 complaints in 2010 to 673 complaints in 2024. We found that neighborhoods with the most complaints, Mission and Bayview Hunters Point, both fell within “Hazardous” redlined districts and had more rat complaints (772) than all neighborhoods that were labelled “Best” (24). Although “Hazardous” redlined districts have the most complaints, the overall time to close a complaint is approximately 84 hours and about 125 hours in the “Best” neighborhoods. Understanding these legacy effects is essential for developing equitable pest management strategies and improving public health outcomes in urban environments.