The tap water supply in Chifeng City, north China's Inner Mongolia, resumed Thursday, two weeks after contamination caused more than 4,300 people to fall ill, but the city's disease control authority has warned residents the water is still undrinkable.

"The water source is clear now, but since the pipeline has just been disinfected, residents should not drink the water, but can use it for washing and flushing the toilet," said a public health official surnamed Jin with the city's disease control center.

By Friday, 4,086 of those who sought treatment for gastrointestinal problems had recovered, and 33 remained in hospitals.

Officials said the water supply was contaminated by rainwater after a storm on July 23.

Jin said Friday that the city had thoroughly disinfected the pipes in the new city center, which supplies tap water to 58,000 people.

"There are 18 residential communities in the area. Our staff have collected water samples from each of the pipeline outlets to these communities to test the quality, after the water supply resumed on Thursday, and the results will be known in 48 hours," he said.

The city government has deployed 18 fire engines to supply water to the affected communities since July 27, and promised free medication for all those affected.

The center's tests showed an excessively high counts of bacteria, including coliforms and salmonella in the tap water when it was tested after people fell ill.

(Xinhua News Agency August 7, 2009)