Final answer:
The EPA regulates water on board aircraft under the Safe Drinking Water Act and enforces quality standards for U.S. waters, including regulating pollutant discharges, under the Clean Water Act.
Step-by-step explanation:
The Environmental Protection Agency (EPA) is responsible for regulating water quality standards in the United States. Thus, the legislation that allows the EPA to regulate water on board aircraft to ensure that the public is not exposed to high levels of bacteria is the Safe Drinking Water Act. This Act empowers the EPA to oversee the safety of public water systems, including those found on aircraft.
Further, the legislation that specifically regulates discharges of pollutants into U.S. waters and regulates the quality standards for surface waters is the Clean Water Act. This Act aims to prevent pollution by setting water quality standards, mandating permits for discharging pollutants, and guiding the nation towards maintaining and restoring the quality of waters to ensure they are swimmable and fishable.