The Environmental Protection Department has rated water quality at 15 beaches 'good' and 18 'fair' for this weekend.

Compared with last week, Big Wave Bay, Deep Water Bay and Repulse Bay have risen from fair to good, and Kadoorie Beach from poor to fair. Clear Water Bay Second Beach has fallen from good to fair.

The changes are generally within the normal range of fluctuation of the bacteriological water quality of the beaches.

Seven gazetted beaches - Anglers', Approach, Ting Kau, Casam, Gemini, Hoi Mei Wan and Lido - are closed to swimmers year round due to poor water quality.

Many beaches are likely to be more polluted than their grades suggest during and after periods of heavy rain. Bathers should avoid swimming at beaches for up to three days after a storm or heavy rainfall.