Selangor water management firm Air Selangor has instructed Tenaga Nasional Bhd to speed up repair works for its Bukit Badong substation so normal water services can resume sooner than Dec 24.

It said the works, which started 8am today, are expected to be done by midnight tonight.

The maintenance work has slashed water treatment plant capacity to 50 to 60 percent, affecting about four million users in the Klang Valley.