If water seepage problems involve the water supply system, owners may appoint a licensed plumber under the Waterworks Regulations (Cap. 102A) for checking the system and carrying out the necessary repair works.  The licensed plumber directory is available on the following webpage of the Water Supplies Department:

https://www.wsd.gov.hk/en/plumbing-engineering/licensed-plumbers/index.html

The Water Supplies Department will not intervene in a private dispute arising from a mild water seepage nuisance where there is no evidence of waste of water.