Only 0.17% of the 20 million water bills issued between April 2005 and October last year were reviewed and eventually rectified upon request, the Water Supplies Department says, adding dispute cases fell by half in 2007-08 on the previous year.

Responding to the Ombudsman's report on alleged overcharging of water bills today, the department said measures have been taken to boost accuracy and prevent overcharging. They include upgrading the online monitoring and internal checking mechanism, and cutting the use of estimation for assessing water charges.

The replacement of old water meters has been expedited. About 1.2 million meters more than 12 years old will be replaced by 2011.

The department will take on board all the Ombudsman's recommendations to improve service. Customers can call 2824 5000 for bill enquiries or to request a review.