The agency said it will randomly test 169 domestic and international passenger aircraft at 14 airports throughout the United States and will publish the results in January.
In addition, EPA announced that 12 major airlines have agreed to conduct more tests of their own on aircraft drinking water and disinfection procedures. The agreement also requires that the drinking water systems aboard planes be flushed every three months.
The increased random inspections by government officials are in accordance with "commitments from U.S. passenger airlines to implement new aircraft water testing and disinfection protocols," EPA said.
In August and September, the EPA tested drinking water aboard 158 randomly selected domestic and international passenger aircraft and found that 12.6 percent did not meet federal standards.
Twenty of the planes that were tested — which ranged from small commuter aircraft and jumbo jets — tested positive for total coliform bacteria, signaling the possible presence of other harmful bacteria. Two planes tested positive for E. coli bacteria, which can cause gastrointestinal illness if it is severe enough.
EPA officials have advised passengers whose immune systems are compromised to avoid drinking water from airplane galleys or lavatories.
The airlines have said through their trade group, the Air Transport Association, that they are confident their drinking water is safe. The EPA summer tests showed that 87.4 percent of the planes tested had water that met the EPA standards. That is only slightly less than the 90 percent compliance among municipal drinking water systems in the United States.
The agreements with the major carriers require the airlines to analyze possible sources of contamination that exist outside aircraft and provide the government with information on their practices in getting drinking water from foreign public water suppliers not regulated by EPA.
"The agreements ... will provide critical additional information, and at the same time provide increased protection to the flying public," said Thomas V. Skinner, EPA's acting assistant administrator for enforcement and compliance.
Signing the agreements with EPA were Alaska Air Group Inc., Aloha Airlines, AMR Corp.'s American Airlines, America West Holdings Corp., ATA Holdings Corp.'s ATA Airlines, Continental Airlines Inc., Hawaiian Holdings Inc.'s Hawaiian Airlines, JetBlue Airways Corp., Midwest Air Group Inc., Northwest Airlines Corp., UAL Corp's United Airlines and U.S. Airways Group Inc.
Separate agreements are still being negotiated with two additional airlines, Delta Air Lines Inc. and Southwest Airlines Inc., EPA officials said.
While the 14 airlines represent the majority of U.S. Flag airlines, the agency said it also is working with smaller, regional and charter aircraft carriers to address the problem.