Clean Water Standards for PFAS Act of 2019 This bill requires the Environmental Protection Agency (EPA) to address certain perfluoroalkyl and polyfluoroalkyl substances, commonly known as PFAS. These man-made substances may have adverse human health effects. A variety of products contain these substances, such as nonstick cookware, waterproof clothing, stain-resistant fabrics, food packaging, and fire-fighting foams. The bill requires the EPA to expand the list of toxic pollutants under the Clean Water Act to include such substances. In addition, the EPA must develop effluent standards and pretreatment standards for the substances.