The state health director on Thursday urged people living in Durham in houses that are more than 20 years old to take precautions with their water.
Dr. Leah Devlin said people who live in such houses with children or women who are pregnant or breastfeeding should have their water tested for lead contamination. She also suggested that the operators of child care facilities built before 1986 test water supplies.
Lead is especially toxic to young children, and can cause brain damage and other developmental problems. Lead in plumbing was banned in 1986.
Devlin's statement is the latest turn since news broke in May that a child was poisoned after drinking the lead-laced water in his family's Durham apartment.
Durham County Health Director Brian Letourneau said his department is sampling water at elementary schools built before 1986. A 2004 sampling showed one school had elevated lead levels in its drinking water. That school now uses bottled water.
In 131 water samples from Durham homes tested for lead in the past two months, about 16 percent have tested positive for lead above the federal limit. Tested houses that were built between 1982 and 1985 showed 44 percent tested positive for high lead in the water. Of the homes built since 1986, none had lead above the federal limit.
Durham officials have encouraged city residents to run their faucets at least three minutes before using tap water for drinking or cooking to reduce the contamination risk. The state also encouraged residents to use only cold tap water for cooking and drinking since hot water can dissolve lead more quickly. Boiling water will not reduce the amount of lead.