He also said, "the situation has yet to improve."
Unsafe levels of organic compounds and heavy metal ions are thought to exist in the current water supply.
The 2009 development ministry survey linked poor water quality with high levels of organic compounds in the country's sources of surface water, the major supplier for urban water plants.
"One day or two, even one year or two, won't show the damage," said Wang Zhansheng, environmental professor at Tsinghua University and a leading expert on water issues. "But high levels of organic compounds will accumulate in the human body and could lead to mutations and chronic diseases, including cancer."