U.S. regulators on Tuesday issued rules requiring airlines to test and disinfect the water served to passengers and used in airplane lavatories. The Environmental Protection Agency (EPA) rules—an attempt to remedy bacteria contamination found in onboard water—establish schedules for how frequently airlines must flush and disinfect the water systems on airplanes and test for coliform bacteria. Coliform is usually not harmful, but it is considered an indicator of the presence of disease-causing germs. The EPA rules apply only to tap water supplied through aircraft water systems, not bottled water. “This rule is a significant step forward in protecting people's health when they travel,” said Peter Silva, the assistant administrator in EPA's water office. “EPA has taken this step to make sure the public has drinking water that meets standards, both in the air and on the ground.”