China has set a timetable for its "sponge city" program, which seeks to help cities better absorb rain to improve the environment, an official said on Friday.

By 2020, 20 percent of cities should have modern sewer systems and infrastructure that allows for efficient absorption of water, with the number rising to 80 percent by 2030.

About 130 cities across the country have mapped plans to turn themselves into sponge cities so far, said Vice Minister of Housing and Urban-Rural Development Lu Kehua.

The program will see the construction of high-level urban sewer systems, new roads, residences, industrial parks and public green areas, according to a statement released after a State Council executive meeting on Sept. 29.

New sewer systems will drain rain water quickly and guide it to collection facilities for recycling.

The government encourages private investors to participate in the construction of the new sewer systems and asks financial institutions to provide support.

Heavy rain often results in floods in cities with outdated sewer systems.

In one case, 79 people died in Beijing after a rainstorm on July 21, 2012.