The city of Houston is under a boil water notice due to a Sunday morning power outage at its East Water Purification Plant. According to Houston Public Works, its water system serves 2.2 million customers.

Residents of the fourth largest city in the country should boil all water used for food preparation, drinking bathing or brushing teeth for three minutes, and avoid using water from refrigerators or ice makers. Those who cannot boil water are advised to use bottled water.

Houston ISD has closed all schools, offices and facilities on Monday in response to the boil water notice.

The boil water notice is expected to be lifted Tuesday morning, after the Texas Commission on Environmental Quality reviews the city’s water samples, according to Houston Public Works spokesperson Erin Jones.

A boil water notice has been issued for the City of Houston ‼️ Everyone should boil the water before drinking, cooking, bathing, and brushing their teeth.More Information Belowhttps://t.co/O5uo7deQBI pic.twitter.com/1Pozmv0imS
— City of Houston (@HoustonTX) November 28, 2022

During the outage at 10:30 a.m. Sunday, water pressure at the plant briefly dropped below required minimum levels. Water pressure in the entire system is currently back above minimum levels for safety, Jones said.

Low pressure hurts water quality and be a threat to public health. A reduction or loss of pressure in a water distribution system can result in backflow, when water flows in the wrong direction, allowing contaminants to enter drinking water.

A boil water notice was issued out of an abundance of caution and to comply with regulatory standards, according to Houston Water Director Yvonne Williams Forrest.

“Our system maintained pressure. We never lost pressure fully,” Forrest told KHOU. “So there was never an opportunity for anything to enter our system. They just fell below the regulatory requirements.”

Gov. Greg Abbott directed state emergency resources to the city to help, and said he has been in contact with Mayor Sylvester Turner.

“We’re currently working to fulfill the city’s request for help with rapid turnaround of water sample results,” Abbott said in a statement.