BRAINERD — Brainerd has extended its order for residents to boil their water before drinking or cooking with it.

Brainerd Public Utilities Superintendent Scott Magnuson said the boil order will run for a week, or until further notice.

Bacteria were found in one of 12 samples tested by the Minnesota Department of Health on Thursday.

BPU said the contamination may have occurred due to loss of pressure in the system from a water main break and the loss of power in a storm.

The utility planned to begin adding chlorine to disinfect the system starting Saturday, then flush the system starting Sunday. It said the chlorine may react with iron or manganese in the pipes and turn the water black or reddish-brown, but it doesn’t pose a health threat.