An article just published by Telegraph Travel from the UK highlights the water purity issues on board aircraft.
Ranked the fourth cleanest airline in world, behind three other Asian carriers, Hong Kong-based Cathay Pacific Airlines has a water purity problem. The Hong Kong Port Health Office which audits water purity on aircraft, collected samples from 22 planes and found that 14 of the samples tested failed to meet minimum hygiene standards.
If you are a traveler, you have likely asked for water on board the aircraft. Usually you are given a sealed bottle of a commercial brand of water. However, if you were poured water from a jug, or if you asked for tea or coffee, you are getting water from the bulk water tanks built into the aircraft. These tanks are filled by commercial water companies at virtually all airports around the world. In Cathay Pacific’s case they provided passengers with bottled water but cautioned passengers not to drink the water or brush their teeth with the water coming from the faucets in the bathrooms on board as this water comes from the on-board bulk water storage tanks.
This is not a new phenomenon. In 2002 the Wall Street Journal studied water taken on 14 different flights. Their study found considerable problems with water quality including Salmonella, Staphylococcus and tiny insect eggs. Furthermore the WSJ reported that as a rule, bacteria levels were much higher than US government limits. Later studies by the EPA and NBC also showed an ongoing problem with water quality on-board aircraft.
Unfortunately the planes of today have not yet advanced to the point they have a steam distiller on-board. That would solve their problems. Meanwhile, be prepared and only drink the bottled water they provide – distilled if you are lucky.