More than 580,000 people will have to stop using running water for three days as the city sanitizes the tap water system, said the municipal government of Inner Mongolia Autonomous Region's Chifeng City Saturday.

The tap water supply is to be resumed in 72 hours if water quality is proved to meet national standards within the period, said a notice issued by the municipal government of Chifeng.

Altogether 4,215 people have sought medication for gastrointestinal illness after the tap water supply was contaminated by rainfall on July 23. No death or serious illness was reported as of Saturday.

The patients complained of fever, diarrhea, stomachache and vomiting after drinking tap water since the night of July 25.

The local government sent 18 fire engines to supply water to the 18 affected downtown communities in Chifeng since July 28. And free medication for all the victims was offered since July 27.

The contaminated well provides tap water for Chifeng's "new city center", a 17-square km area with a population of 58,000, said Zheng Fengjun, a local official.

(Xinhua News Agency August 2, 2009)