This study found that the installation of public restrooms as part of the San Francisco Pit Stop program was associated with a long-term reduction in the rate of reports of exposed feces. The decline in feces reports in the six-month period after the installation of new restrooms was driven by reductions in the Tenderloin, the Mission, Golden Gate Park and, to a lesser extent, SoMa. The provision of attendants at existing restrooms also led to significant reductions in the rate of feces reports in the Mission, the Castro/Upper Market and the Financial District/South Beach. These results support the hypothesis that Pit Stop public restroom interventions help reduce the incidence of open defecation due to improved restroom access for PEH. Additionally, the provision of restroom attendants may improve the cleanliness, maintenance and safety of the facilities, increasing the use of previously unsafe or unsanitary restrooms. This aligns with previous research showing that PEH will often avoid restrooms that are broken down, unclean, not stocked with supplies, or unmonitored (due to safety concerns).1,5 The addition of new restrooms and the provision of attendants may improve access to and the quality of sanitation facilities, thus reducing open defecation for vulnerable populations without access to other sanitation solutions.
In 2019, the San Francisco point-in-time count of PEH estimated that District 6, which contains the Tenderloin and SoMa neighborhoods, had 3,656 homeless residents, double the amount in the next-highest district.4 Of these, 1,990 (54%) were unsheltered. Unsheltered individuals lack access to the limited shared sanitation facilities offered by homeless shelters and other housing programs and are more likely to have to resort to open defecation.1,5 Results from this study suggest that improvements in restroom quality and accessibility have a more appreciable impact in areas where the need for them is higher. The Tenderloin and SoMa had the highest number of feces reports compared to other neighborhoods. This suggests that these neighborhoods may have the highest incidence of open defecation, which aligns with the high prevalence of unsheltered PEH in these areas.
We found that Pit Stop locations in the Tenderloin had the largest average reduction in reports of exposed feces following the interventions. Despite the high number of feces reports and the high prevalence of homelessness in SoMa, there was only a near-significant decline in the post-intervention rate of feces reports near SoMa Pit Stops. We also observed a significant decline in the post-intervention rate of feces reports in the Mission, which had the third highest mean number of reports of exposed feces near Pit Stop locations. According to the 2019 point-in-time count, there were 643 total PEH including 257 (40%) unsheltered PEH in the Mission District (District 9).4 Though the reported population of PEH in the Mission is much lower than in the Tenderloin and SoMa, the estimated total number of PEH in the Mission District is increasing; District 9’s point-in-time count was 410 in 2015 and 552 in 2017.22,23 The Mission also shares its southern and eastern borders with District 10, which had the second highest point-in-time count in 2019 (1,820 PEH) and a single Pit Stop restroom located in Bayview Hunters Point.4 Notably, there were eleven Pit Stop interventions implemented in the Tenderloin. In contrast, there were only four Pit Stop interventions implemented at three locations in SoMa and five Pit Stop interventions implemented at five locations in the Mission which were spread across a large area. Other city-based studies have documented how sanitation coverage can reduce fecal contamination. In a study of low-income urban neighborhoods of Accra, Ghana, increased spatial clustering of sanitation coverage was associated with reduced environmental fecal bacteria contamination.24 The Tenderloin Pit Stops may have had a greater impact on reducing fecal contamination because more Pit Stop restrooms were clustered together within a smaller area, providing more sanitation facilities within a short walking distance of many PEH. Given the high number of fecal reports observed in SoMa and the Mission, increasing the density of Pit Stop restrooms near known areas with unsheltered people would result in more comprehensive access to sanitation facilities, potentially yielding greater reductions in open defecation.
Unsheltered individuals in neighborhoods with poor access to sanitation may be at greater risk of exposure to fecal contamination from open defecation in their surrounding environment. Our results suggest that in San Francisco, unsheltered individuals in the Tenderloin, SoMa, and the Mission are most at risk of exposure to feces based on the high number of 311 exposed feces reports. Feces of humans, as well as dogs, may contain harmful pathogens that pose public health risks to the homeless communities in these neighborhoods. A 2018 study in Atlanta, Georgia detected harmful pathogens in 23% of human fecal samples collected from various open defecation sites.25 Poor sanitation is a known contributing factor to the spread of infectious diseases in communities worldwide.26 Additionally, homelessness has been identified as a potential risk factor for antimicrobial resistant infections in San Francisco, CA and elsewhere.8,27,28 PEH are frequent visitors of emergency rooms, often due to mental health needs or substance abuse, increasing their risk of exposure to drug-resistant pathogens that are difficult to treat.29,30 Individuals who acquire drug-resistant infections in the hospital may spread drug resistance to others in their community, especially where sanitation and hygiene conditions are inadequate. Future studies should identify pathogens in exposed feces in the urban environment of San Francisco and characterize pathogen carriage among PEH to determine the extent to which exposure to human feces drives infections in these vulnerable communities.
Our analysis has some limitations, the first being the use of 311 Human/Animal Waste reports as a proxy for incidence of open defecation, which may be prone to user error and misclassification. Reports that are correctly classified as Human/Animal Waste may not correspond to a human open defecation event, but may instead be animal feces (especially dog feces), though we were unable to distinguish between reports for human versus animal feces. Animal feces are an important source of exposure to fecal pathogens that can cause diarrheal diseases and other adverse health effects in humans.31 Pit Stops are equipped with dog waste bags so it is possible that they reduce both human and animal fecal contamination. Further research is warranted to determine the impacts of Pit Stop interventions on reducing animal versus human fecal contamination in San Francisco.
Second, season may have played a role in both the incidence of open defecation and the incidence of reporting exposed feces. In this analysis covering six years of data, reports of feces near Pit Stop interventions were highest in the spring and summer months. Existing literature suggests that seasonal and climatic factors of environmental fecal contamination are variable and context-specific. For example, levels of fecal indicator bacteria in surface waters are often higher during hotter, drier months in tropical climates, while levels of fecal indicator bacteria in temperate urban climates may be higher during months with more rainfall.32 This is somewhat consistent with our findings, since spring months in San Francisco are temperate with some rainfall, and the summer months are dry with relatively higher temperatures. Season may also influence the frequency of reporting, as pedestrian traffic may decrease during the colder, rainy months, thereby reducing the chance that someone will encounter and report exposed feces.
Third, other time-specific factors, such as changes in public awareness of fecal contamination or the 311 reporting system, may be confounders. Between August and October of 2018, there were at least three events that led to increased media coverage in the San Francisco chronicle and elsewhere: 1) in August, San Francisco DPW announced its plan to create a ‘Poop Patrol’; 2) in September, an online report about 311 feces reports in San Francisco and other major cities called “Doo-Doo, the New Urban Crisis” was published; and 3) in October, the creation of a free phone app called SnapCrap, designed to make 311 feces reporting in San Francisco more user-friendly, was announced (Supplemental Materials, Appendix A). Media events like these may account for some fluctuations in feces reports throughout the study period. It is possible that there was unmeasured confounding due to changes in public awareness, pedestrian traffic, or misclassification of animal feces as open defecation. While 311 feces reports can be a useful tool to plan and evaluate sanitation interventions, additional research is needed to validate these reports as an accurate and reliable indicator of open defecation over time.
This study has several strengths. First, our interrupted time series analysis utilized a multiple baseline design (i.e. interventions beginning on various dates), which inherently controls for time-specific confounding factors. Second, this approach allows for each intervention to serve as its own control during the pre-intervention period, controlling for location-specific factors at each intervention site. Third, we assessed long-term changes in the rate of feces reports per week over a 12-month period, preventing short-term time-specific confounding from biasing our results.
The UN General Assembly passed Resolution 64/292 in 2010 (and reaffirmed in 2018) declaring that adequate access to safe water and sanitation are essential human rights.33 California became the first state to legally recognize the human right to water for drinking, cooking and sanitary purposes with the passage of Assembly Bill 685 in 2012.34 However, this bill failed to recognize the human right to access to sanitation, and basic sanitation needs remain unmet in the most vulnerable populations of California. According to the 2019 point-in-time count, there are at least 108,432 unsheltered PEH in the state of California and at least 5,180 unsheltered PEH in the city of San Francisco.4,35 The Pit Stop Program improved access to sanitation facilities in San Francisco neighborhoods with the highest number of unsheltered people. This study provides evidence that a public sanitation program can reduce reports of exposed feces in public spaces, especially in neighborhoods with the greatest need for sanitation facilities. Though the Pit Stop Program attempts to fill the gap in sanitation access in San Francisco despite the lack of state legislation to do so, explicitly recognizing basic sanitation as a human right would drive other cities across California to improve sanitation access for all.