Is Airline Drinking Water Safe for Consumption?

Random tests of the water aboard 169 U.S. passenger planes conducted by the Environmental Protection Agency in November and December found contamination by fecal coliform bacteria on about 17 percent of them — almost 5 percent more than was found in tests done in August and September.

There's a clue to the source of the contamination: Only 4.8 percent of the faucets in airplane galleys produced contaminated water, but 15.5 percent of the lavatory faucets did.

"It's not hard to speculate why the bathrooms might be dirtier than the galleys," says Tom Skinner of the EPA's Office of Enforcement and Compliance Assurance.

The EPA is investigating the sources of the contamination. Among the possibilities: local water supplies, unsanitary water-hose nozzles, incorrect tank-filling procedures, tainted pumping systems or the passengers themselves.

Because airliners can take on water several times a day in different cities, some overseas, the agency says it's difficult to isolate a contamination source.

Coliform bacteria aren't usually dangerous, but might indicate the presence of organisms that can be a threat to public health.

The EPA advises passengers with compromised immune systems — such as cancer and transplant patients and people with HIV — to request canned or bottled drinks and try to avoid coffee and tea made with tap water.

Good news is that no dangerous bacteria were found, says Doug Willis of the Air Transport Association, the airline industry group.

The summer tests found two planes contaminated with E. coli, a potentially deadly bacteria that can cause diarrhea and nausea.

The industry's position is that an airliner bathroom is no different than any other public bathroom.

"Lots of people use them. You need to take precautions to protect yourself," Willis says. "I suspect our lavatories are no different than the public restrooms at the EPA."

The major airlines signed memorandums of agreement with the EPA requiring they disinfect the trucks that bring water to planes monthly and the tanks on planes that hold water every three months. They agreed to test their water systems once a year.

While news that the water may have traces of feces is "a fairly gross variable," Skinner says it's no reason to panic.

"People have been flying for 40 years in the this country and there haven't been reports of mass outbreaks of intestinal illness on any given flight. And conditions haven't changed for the worse in the last 40 years," Skinner says.

(Source: EPA's airline water FAQ and more)