The Water Supplies Department (WSD) on Friday said a staff member had lost a portable electronic device containing the names and addresses of 495 people from three buildings in Fortress Hill during field metre-reading work.
The case was reported to the department on Wednesday, the same day the device was lost.
In a statement, a department spokesman said that aside from one person whose telephone number was leaked, the breach did not contain any identity card numbers or other personal information.
The spokesman added that the department had notified the affected individuals, the Office of the Privacy Commissioner for Personal Data, and the Digital Policy Office, and reported the incident to police.
He said the department would also conduct a detailed review of the equipment and field metre-reading procedures, and will explore measures to strengthen data protection.
