BEIJING, Jan. 4 -- China plans to apply progressive water tariffs on all urban residents by the end of 2015 with top rates at least triple base prices in the latest move to encourage conservation.

The pricing system, already in place in cities including Shanghai, charges extra for consumption beyond “basic needs.”

Local authorities should work out pricing systems that include at least three tiers, the National Development and Reform Commission and the Ministry of Housing and Urban-Rural Development said in a joint statement yesterday.