Airing water: Director of Water Supplies Ma Lee-tak speaks on a radio talk show.

The voluntary water efficiency labelling scheme will start September 10.

Speaking on a radio talk show today, Director of Water Supplies Ma Lee-tak said the scheme will cut water consumption by 10% when fully implemented in 2030.

He said the department will first invite shower suppliers to register for the scheme, which will extend to taps and washing machines in the next phase.

Hong Kong loses 21.8% of its water annually through water main leakage. Mr Ma said the water mains replacement and rehabilitation programme has been expedited and forecast it will cut water loss to 15% when works are complete in 2015.

The department has also invited the University of Hong Kong to conduct 15 months' research on improving sea water processing to prolong the life of seawater mains.