Brazil was home to the second largest open-air dump in the world, Estrutural, which officially closed in January of 2018; however, many dumpsites throughout the country continue to operate informally. Prior to government-recognized closure, there were about 1200 waste pickers working at the dump. These workers were subject to a myriad of occupational and environmental risks; one primary hazard involved exposure to contaminated water, which significantly affects health and quality of life. As part of the official closure plan for Estrutural, a study was conducted to determine the occurrence of waterborne diseases and rates of intestinal worms among the workers. A convergent parallel mixed methods approach, using a cross-sectional study and semi-structured interviews, sought to uncover answers to these objectives. There were 1025 waste pickers used in this study. Data confirmed waste pickers experienced continuous bouts of waterborne disease cases through episodic diarrhea (24.9%), intestinal worms (12.6%), hepatitis A (1.7%) and leptospirosis (0.7%). People who lived in unregulated areas (favelas) had increased risk of diarrhea (OR = 1.72) and those who did not use filtered water were at increased risk of intestinal worms (OR = 1.87) and diarrhea (OR = 1.5). Qualitative and quantitative data confirmed that many workers suffered from waterborne diseases, and that women were at greater risk than men. These findings highlight unsanitary and poor occupational health conditions for waste pickers at dumpsites, which likely continue despite official dumpsite closures. Moreover, this data provide evidence of supplemental occupational hazards to assess at dumpsites worldwide, especially for women.