The Continuing Fear Of Bad Plane Water
The horror stories continue: "Flight attendants will never drink
tea or coffee on board because it's made from water
believed to be frequently contaminated."
Coffee and tea are made with water stored in on-board tanks,
not water brought aboard at each stop in plastic bottles.
The on-board tanks are the responsibility of the airline.
They can be topped up as needed at any airport, although the
airlines try to refill the water tanks at the aircraft's home airport
in order to save mony.
The tanks are generally emptied completely only when the water system
is being serviced or during periods when the aircraft will sit idle
in cold weather.
These horror stories about on-board water tanks seem to go back to
the early 2000s.
2017 Travel and Leisure article
was based on a Business Insider article, which
quoted The Association of Flight Attendants - CWA as saying that they
had pushed for a U.S. regulation "over 15 years ago", meaning in 2002 or
Some airline models have had on-board lavatories and sinks for some time.
Below is the starboard lavatory from a Douglas DC-7 at the Smithsonian's
National Air and Space Museum in Washington D.C.
The DC-7 was the last major piston-engined transport aircraft made by
the Douglas Corporation.
348 were built from 1953 to 1958.
In 2004 the U.S. Environmental Projection Agency
sampled the water
in 158 airliners.
On 20 planes they found
and on 2 planes that coliform bacteria included Escherichia coli,
which is almost always the result of fecal contamination.
Drinking water in the U.S. is regulated under the Safe Drinking Water Act
which was established by the EPA in 1974 and revised in 1986 and 1996.
The EPA also developed the National Primary Drinking Water Regulations
It contains mandatory water quality standards for public water systems,
limiting disinfectants and their by-products, inorganic and organic chemicals,
radionuclide, and microorganisms.
The EPA has a
quick reference guide
to their Aircraft Drinking Water Rule.
The regulation itself is CFR Title 40, Chapter 1, Subchapter D,
Part 141, Subpart X.
The regulation calls for "routine disinfection and flushing" of the
water system, and "periodic sampling".
However, it's all based on self-inspection and following the
aircraft manufacturer's recommendations.
Obviously a manufacturer isn't going to say "Our planes have pretty
dirty water tanks, you'd better check them frequently."
The regulation only requires that the air carrier inspect the on-board
water system at least every five years and then resolve
any problem within the following 90 days.
Health Canada conducted a similar study
They collected 431 water samples and found that 15.1% of the aircraft
tested positive for total coliform bacteria, and 1.2% for E. coli.
issued a warning to air travelers
telling those with compromised immune systems to avoid beverages
prepared from on-board tap water.
The existance of the EPA bothers some people.
Ayn Rand, Rand Paul, and Paul Ryan walk into the Objectivist Bar.
It's in an ideal Objectivist society, so there are no regulations.
The bartender serves them wood alcohol and everyone dies.
The Air Transport Association responded to the EPA report expressing
skepticism over the statistical meaning of a sample of just 1% of the
They especially objected to the EPA sampling procedures, as they had
used was samples collected from the taps in the lavatories.
Given the tiny space and violent flushing, it would a surprise if
fecal bacteria weren't found on all surfaces in an
article in the International Journal of
Environmental Research and Public Health
went into deeper detail, and in 2017 they published an
update in PLOS One.
They took a total of 154 water samples.
Perhaps most significantly, they took samples in the fore and aft galleys
but not in the lavatories.
They found 37 bacterial species from eight classes: the
They concluded that the bacteria are usually introduced in the vehicles
that transport water to the planes.
The bacteria isn't in the original source,
it is transferred from the truck to the plane.
They found a 200-fold increase in bacterial count going from the water
source to the water service vehicle!
(counted as the number of colony-forming units per volume of water).
The water service vehicles vary widely, but in general they are much more
contaminated than the water sources.
The on-board water supply tanks are then conducive for further growth of
the microorganisms introduced by the service vehicle.