The AA’s "triple water system" helps reduce the airport’s freshwater demand by over 50% each year.

Hong Kong International Airport (HKIA) is well equipped with large-scale water-saving facilities, and the Airport Authority (AA) implements a number of measures to minimise daily water usage.

Our Story

Total Water Management

HKIA adopts a "triple water system" to improve the efficiency of its three major water sources: freshwater, seawater and treated wastewater.

Seawater is used for flushing toilets and as the cooling medium in the air-conditioning systems of major airport buildings. This substantially reduces the use of freshwater.

Meanwhile, wastewater from terminal building kitchens, washroom sinks, and aircraft catering and cleaning activities is collected and processed in an on-site wastewater treatment plant, and reused for landscape irrigation.

This "triple water system" helps us reduce our freshwater demand by over 50% each year.

Details of the AA’s water management performance are available in the AA Sustainability Report 2020/21.

Preventing marine pollution

Preventing Marine Pollution

The AA implements various measures to manage sewage and storm water discharges. These include:

  • Deploying extensive petrol/ oil interceptors in areas where a pollution risk exists, including apron areas and carparks;
  • Installing spill traps at storm water outfalls; and
  • Discharging storm water away from the potentially sensitive southern sea channel.

The AA regularly monitors HKIA’s impact on the marine environment caused by sewage, storm water discharge and construction activities. Results indicate that cooling water and storm drain discharges from the airport do not have adverse impact on local water quality.

Aircraft dry wash

Aircraft Dry Wash

In 2019, the AA approved Hong Kong Aircraft Engineering Company Limited (HAECO) and China Aircraft Services Limited (CASL) to carry out dry wash on the maintenance apron at HKIA. Aircraft dry wash is a technique that involves little or no water in cleaning the aircraft. Compared with wet wash, dry wash is estimated to use 90% less water and produces less effluent.

The AA has also worked with airport business partners to develop Dry Wash Procedures to ensure the cleaning processes are performed in accordance with environmental, health and safety requirements.

Quick Facts


The AA’s “triple water system” has served HKIA since 1998


Over 50% of freshwater demand has been reduced through the adoption of the “triple water system”


Using seawater for flushing requires just 25-50% of the energy required if the same amount of freshwater were used