Sewer issies reported to 311
Geographic Unit of Analysis:
|Sewer overflow issues reported to 311 (2009-2014)|
|Neighborhood||Number of reports||Reports per sqmi|
|Financial District/South Beach||346||307.9|
|Golden Gate Park||7||4.1|
|South of Market||483||545.8|
|West of Twin Peaks||1,168||381.9|
Sewer overflows can be an indication of poor storm water management. Rainwater flooding on streets can lead to water inundation in homes and business, causing property damage and mold growth, and possible respiratory illness as a result. Discharge of untreated sewage when sewer systems are overloaded can lead to vectorborne and waterborn diseases.a
In general, sewer overflows are more common on the eastern side of San Francisco. The neighborhoods with the most 311 complaints for sewer overflows per square mile are Chinatown, Hayes Valley, Bernal Heights, Castro/Upper Market, and Nob Hill. An analysis done by staff at SFDPH indicates that many of these neighborhoods also have underground creeks that were paved over during development.a
311 records with requests types defined as "sewage backup," "sewer water storm conditions," or "sie swere issues" were derived from San Francisco’s OpenData Portal (DataSf) and were mapped using the Point Density tool in ArcGIS.
Because 311 records are based on user-reported data (largely residents who phone-in complaints), limitations and biases are inherit to the data. User-reported flooding data may over-represent neighborhoods with an especially high population density or underrepresent neighborhoods with low density populations. Additionally, 311 calls can be duplicative or be misclassified and 311 records do not validate caller’s complaints. While research should be conducted to better understand this tools validity in detailing the frequency and location of flooding, it can be useful in understanding where the public perceives flooding occurs.
San Francisco Department of Public Health. Climate and Health Understanding the Risk: An Assessment of San Francisco’s Vulnerability to Flooding & Extreme Storms. Winter 2016. Available at: https://extxfer.sfdph.org/gis/Flooding/SFDPH_FloodHealthVulnerability2016.pdf