A SEVEN-YEAR-OLD boy drowned in a private pool in Sai Kung yesterday. A decoration worker who was walking past the pool in Moon Wu Garden, Pik Sha Road, noticed Yip Ching-yeung unconscious in the water and pulled him out. The boy was certified dead on arrival at the United Christian Hospital. Ching-yeung's father, a property agent who lives in Moon Wu Garden, was at work at the time of the incident. The boy went swimming in the pool while his maid was at home doing the housework, police were told.