Local authorities said the blue discoloration found in tap water at a residential compound in Zunyi, Guizhou province, likely resulted from a fault in the compound's internal pipe network.

In an official statement released Sunday, the local water affairs department confirmed the discolored water but said water quality at the compound's intake point met safety standards. Supply pipelines and water samples have been sent to laboratories for testing.

The statement added that, in response to residents' health concerns, the local government has organized medical checkups for homeowners and will provide treatment if any health issues are found.

The water authority said it will take targeted actions to address the cause of the water-quality incident to ensure residents have access to a safe water supply. A local government response team is investigating. Any organizations or individuals found to have violated laws or regulations will be held accountable under the law.

One resident said the water company replaced parts of the compound's piping on Dec 5, and that the removed pipes showed signs similar to peeling paint. The resident also said the company had repeatedly assured residents that the water was safe after earlier incidents, yet traces of blue water continued to appear from some neighbors' taps until a few days ago.