Some 140 hectares, of 340 covered by the airport, consist of impervious surfaces (runway, tarmac and buildings). The large amount of runoff water is under qualitative and quantitative control before joining the Rhone River or the Lake Geneva.

Runoff water from the runway, tarmac and taxiways absorbs substances spread on the ground. Two products are especially monitored: hydrocarbons spilled accidentally and de-icing products used in winter to free the runway and aircraft from ice. Their impact on the natural environment is reduced by eleven separators which retain hydrocarbons and solids from the runway and most of the tarmac and taxiways. A suction sweeper draws up residues of each de-icing operation.

Waste water from the airport comes from the sanitary facilities, drainage of the aircraft toilets, washing and repair of aircraft and vehicles, kitchens and restaurants and the various technical workshops.

This waste water is pre-processed on site if needed and then channelled through the sewage disposal to a sewage treatment plant in Geneva canton. Genève Aéroport does not have its own plant. The capacity of the cantonal plant enables all the effluents from the airport to be treated under the best possible conditions.

A deep ground water table lies beneath the tarmac, runway and taxiways. It is protected from surface water infiltration by a stratum which is practically impervious and has a thickness of nearly 30 metres. The protection provided by this stratum reduces the pollution risk of the water resource by airport activities.

A Drainage Master Plan, which is a management and planning tool for the drainage system of the airport, is being drawing up.

The aims of this plan are to provide a detailed report on the condition of the existing pipes, to ensure compliance with legal requirements and cope the new pipes with future airport development. The results will be incorporated in the information system of Geneva airport.