Twenty-four beaches have been rated 'good' in the Environmental Protection Department's latest water quality gradings.

Seven other beaches are 'fair', one is 'poor' and one is 'very poor'.

Chung Hom Kok Beach grading has been lowered from 'good' to 'fair' and Ma Wan Tung Wan Beach from 'fair' to 'very poor'.

The department said the changes are generally within the normal range of fluctuation of the bacteriological water quality of the beach except for Ma Wan Tung Wan Beach. It is looking into the reason for the deterioration at Ma Wan Tung Wan Beach

Seven gazetted beaches - Anglers', Approach, Ting Kau, Casam, Gemini, Hoi Mei Wan and Lido - are closed to swimmers year round because of poor water quality. The public should not to swim at these beaches.

As beaches are likely to be more polluted than their grades suggested during and after heavy rain, bathers are reminded not to swim at beaches for up to three days after a storm or heavy rainfall.