Descriptive Title:

Sewer issies reported to 311

Geographic Unit of Analysis:


SFDPH is in the process of gathering data for this indicator.
Sewer overflow issues reported to 311 (2009-2014)
NeighborhoodNumber of reportsReports per sqmi
Bayview/Hunter's Point 1,598 308.9
Bernal Heights 1,070 992.6
Castro/Upper Market 808 942.6
Chinatown 239 1,063.90
Excelsior 1,117 802.3
Financial District/South Beach 346 307.9
Glen Park 329 492.2
Golden Gate Park 7 4.1
Haight Ashbury 446 801.1
Hayes Valley 519 1,058.30
Inner Richmond 670 900.5
Inner Sunset 790 554.9
Japantown 64 530.3
Lakeshore 14 5.5
Lincoln Park 2 5.1
Lone Mountain/USF 275 474.7
Marina 452 446
McLaren Park 4 6.5
Mission 1,408 794.9
Mission Bay 76 96.7
Nob Hill 374 919.3
Noe Valley 728 745.8
North Beach 385 777.4
Oceanview/Merced/Ingleside 619 587.7
Outer Mission 648 645.3
Outer Richmond 1,304 728.2
Pacific Heights 409 514.3
Portola 448 542.5
Potrero Hill 640 512.3
Presidio 15 6.3
Presidio Heights 249 495.7
Russian Hill 330 668.7
San Francisco 20,884 446.8
Seacliff 113 530.8
South of Market 483 545.8
Sunset/Parkside 1,781 421.2
Tenderloin 249 633.9
Treasure Island 12 13.5
Twin Peaks 70 105.6
Visitacion Valley 398 650.5
West of Twin Peaks 1,168 381.9
Western Addition 227 389.1

Why Is This An Indicator Of Health and Sustainability?

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

Interpretation and Geographic Equity Analysis

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.

  1. 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:

    Climate and Health
    Understanding the Risk:
    An Assessment of San Francisco’s
    Vulnerability to Flooding & Extreme StClimate and HealthUnderstanding the Risk:An Assessment of San Francisco’sVulnerability to Flooding & Extreme Storms