BEIJING, Jan. 3 -- All cities in China should be charging tiered prices for household water by the end of 2015, to encourage people to use less water.

The guidelines published on Friday by the National Development and Reform Commission and the Housing and Urban-Rural Development Ministry,suggest a three rate structure, charging more to homes which use more.

The structure will be based on average monthly household water consumption. The first tier applies to 80 percent of average consumption; the second tier to 95 percent.

The price differential between the three tiers should be no less than 2:3:6, and greater in areas where water is more scarce.