The Fangshan water authority in Beijing is investigating a report that one of the capital's sources of drinking water may be polluted.

The micro blog said the Juma River has turned "white," which signals severe pollution upstream.

The water authority said the pollution might have come from nearby Hebei province. The authority sampled water from different parts of the river as part of its investigation.

The authority has promised to continue checking the problem over the next two days, the Beijing News reported on Friday.

Sterilization equipment is in all nearby villages, and affected regions are provided with emergency-use water. According to the report, more than 340 wells in 181 villages are affected.