About 70 percent of Shanghai's population will drink higher quality water from the Qingcaosha Reservoir in the Yangtze River within five years, authorities said yesterday.

The Shanghai Water Authority said last night that the water supply system will be altered next year with the construction of a new main water source, the Qingcaosha Reservoir. Most of the city's population will start to enjoy cleaner water from the reservoir than they currently do with water from the Huangpu River.

Officials said the quality of tap water has been a problem for years as the city did not have high-quality water sources. But the situation will change once the 17-billion-yuan (US$2.49 billion) reservoir project is completed next year.

Zhang Yifeng, director of the Shanghai Water Authority, said when the pipes connecting the reservoir to urban areas are finished, the quality of urban water service will improve. Zhang said 70 percent of the population, in the city's Changning, Xuhui, Luwan, Jing'an, Hongkou and Yangpu districts, will benefit from the new source of water.

The 70-square-kilometer reservoir is next to Changxing Island and will draw water from the Yangtze River.