The rain that falls onto the Kansai International Airport flows into the rain water drainage pipes at the surface and goes into the sea. Initially, the drainage pipes were installed at an angle so that the rain water flowed into the sea naturally. However, the depth of the settlement near the seawall is greater compared with the center of the island. The uneven settlement decreased the angle of the drainage pipes and reduced the natural flow of water to flow into the sea.

In order to solve the problem above, KIX has been installing drainage pumps at the exit points to the sea so that the water flows out smoothly. The drainage pumps are equipped with a feature to manage extreme rainfall (55mm per hour).

KIX has been installing the drainage pumps since 2001. The installation of the drainage pumps was completed in June 2005.