CHAPEL HILL, N.C. A water emergency ended and North Carolina’s flagship university opened again Sunday after a broken water main and problems at a water treatment plant. The Orange Water and Sewer Authority said its operations returned to normal and the utility’s water storage tanks had refilled. Water testing Sunday confirmed the authority’s water was safe to drink.

The utility also said it canceled a boil-water advisory for one Chapel Hill neighborhood and stopped receiving water from the city of Durham and Chatham County. The problem began Thursday when an excess amount of fluoride was introduced to water at a treatment plant. Fluoride is added to water to prevent tooth decay but can be harmful in excessive amounts. The water authority said it stopped the over-fluoridated water from reaching its distribution network.

The utility began getting water from Durham, but a supply pipe broke early Friday, leaking up to 1.5 million gallons of water and causing a fall in water pressure needed to keep harmful bacteria from growing. Additional water testing was completed Sunday morning to confirm that the water was safe to drink. While water conservation is always a good idea, normal use is now allowed, according to OWASA.

OWASA is no longer receiving water from the Durham as of about 10 p.m. Saturday and ended its transfer of water from Chatham County at about 6 p.m. Saturday. At about 2 p.m. Saturday, the Orange County Health Department and OWASA lifted the “Do not drink and do not use” declarations issued Friday for OWASA water.

A boil water advisory for about 250 residences along Foxcroft Drive in Chapel Hill also was lifted. The water shortage and contamination was due to a water line break Friday. The pipe repair was completed Saturday but area residents emptied local stores of water, and local schools, UNC and restaurants were forced to close. Restaurants and other local businesses were allowed to reopen to the public Saturday afternoon after the “do not drink and do not use” declarations were lifted. While several area grocery stores and other retailers sold out of bottled water quickly after the water shortage began, shipments arrived later Friday and Saturday to meet the need.

The water shortage, which was expected to stretch into Sunday night, caused the University of North Carolina at Chapel Hill to postpone the men’s basketball game against Notre Dame until Sunday and move the game to the Greensboro Coliseum. UNC reopened and resumed normal operations by 10 a.m. Sunday.

“We apologize to customers for the significant disruption and inconvenience due to the need to cease use of OWASA water from Friday morning to mid-afternoon Saturday,” OWASA said in its Sunday statement. “We deeply appreciate and thank the Carrboro-Chapel Hill community, the City of Durham, Chatham County, the Town of Hillsborough and other partners and volunteers for their excellent cooperation, understanding and support in the recent water supply emergency.”

Due to fluoride overfeed at the Jones Ferry Road Water Treatment Plant Thursday, it was necessary for OWASA to shut down the treatment plant and receive water from neighboring utilities. “We are investigating the fluoride overfeed and water line break, and will report to the OWASA Board of Directors and the community at a later date,” OWASA said in the statement.