PFAS Detection Act of 2019 This bill sets forth requirements for detecting and sampling perfluorinated compounds. Perfluorinated compounds are man-made and may have adverse human health effects. A variety of products contain perfluorinated compounds, such as nonstick cookware, waterproof clothing, stain-resistant fabrics, food packaging, and fire-fighting foams. The bill requires the U.S. Geological Survey (USGS) to establish a performance standard for the detection of perfluorinated compounds. Using such standard, the USGS must carry out a nationwide sampling to determine the concentration of perfluorinated compounds in estuaries, lakes, streams, springs, wells, wetlands, rivers, aquifers, and soil. The sampling data must then be used to inform and enhance assessments of exposure, likely health and environmental impacts, and remediation priorities.