Since security rules were tightened several years ago, passengers are not allowed to take more than a tiny drop of water (3 fl oz / 90ml in the U.S. and 100 ml in Europe) through security. This has been a nuisance for the travelling public, as many people have to purchase a bottle of water again beyond security to replace the one left behind.

Alternatively, passengers can bring an empty bottle through security and fill it up from a tap on the other side. However, as The Economist last year blogged, surprisingly few airports have made water fountains available or have hidden them in hard to find corners (by the way Amsterdam Schiphol Airport's new "Ambient Gate" is a welcome exception). Furthermore, bathroom sinks and public drinking fountains are often not in a very hygienic state, and many aren't designed to allow for a easy fill of a bottle.

Global Tap Hydration Stations

San Francisco International Airport (SFO), already one of the most environmentally active airports in the U.S., has come up with an innovative solution to solve this situation and to reduce plastic waste. The airport has installed two tap water "hydration stations" in the "airside" part of the terminal and encourages passengers to carry their emptied plastic containers through security.

The water bottle refill stations were designed by IDEO and developed by a company called Global Tap. Users place their bottle under a spigot, press a button and tap water flows vertically into the container. The blue slender question mark-shaped hydration stations are also easy to be recognized by travellers and have been installed near the food court in SFO's Terminal 3 (used by United Airlines) and at the airport's International Terminal.

The Global Tap filling stations are the first to be installed in a U.S. airport and are part of a city-wide campaign in San Francisco to curb bottled water consumption, which has huge negative impact on the environment. Fifteen filling stations have been installed at various locations throughout San Francisco to provide the public with access to free high-quality tap water. According to the San Francisco Public Utilities Commission, the San Francisco-region has some of the best tap water in the world, fresh from the Hetch Hetchy reservoir in Yosemite National Park. However, one billion water bottles still end up on California landfills each year.

SFO's "Green" Terminal 2

Water bottle refill stations will also be a feature of SFO's renovated and redeveloped Terminal 2 (T2), which is scheduled to open in mid-April 2011. The water refill stations at T2 have a more traditional design than the Global Tap stations and will also be placed after the security checks. For those that want to purchase bottled water after having passed security, vendors at the new T2 will be only allowed to sell water in compostable bottles. SFO's T2 will be the first airport terminal in the U.S. that is LEED Gold-certified. And it is designed to set new green standards.

Carbon Kiosks, Hybrid Car Rental

The "hydration stations" aren't the first "green" innovation at SFO. In previous initiatives, the airport provides a discount to passengers who rent hybrid cars - which the airport says met with some success - and installed self-service "carbon kiosks" so passengers can purchase carbon offsets for their air travel. However, these kiosks reportedly haven't been as successful as hoped.