Legal action is being taken on three seafood shops on Nelson Street, Mong Kok, for using flush water in their tanks.

The cases were discovered after Water Supplies Department checks on August 28.

There were eight cases prosecuted in 2004, five in 2005 and four in the first eight months of this year.

The Food & Environmental Hygiene Department mounted two operations last month, but found no cases of flush water being used.

Regular inspections will continue.