Houston boil water advisory for 2 million people could last until Tuesday, mayor says

More than 2 million people across Houston faced a boil water order Monday that could last until Tuesday after a power outage disrupted the city's water system.

Schools were closed Monday, and many businesses were forced to shut down for the day.

Water pressure dropped below the Texas Commission on Environmental Quality’s required minimum Sunday at the East Water Purification Plant, authorities said. Mayor Sylvester Turner, speaking at a briefing Monday, apologized for the disruption and said he was optimistic test results would come back clean.

"It is our hope that we can get positive word late, late (Monday) night or early tomorrow morning because we would like to see schools resume," Turner said.

He said an electric transformer and a backup both failed, causing the power outage and decline in water pressure. He said he has ordered a diagnostic team to investigate what happened to ensure it won't happen again.

Turner said the power failed late Sunday morning and was restored about two hours later. About three hours later, at  3:30 p.m. local time, water pressure was restored. A few hours later the decision to issue the advisory was made as a precaution, Turner said.

The mayor said 16 sensors fell below 20 PSI for two minutes, which triggered the emergency. Turner tweeted that when the water pressure drops precipitously, "there is a regulatory requirement to issue a boil water notice" even if authorities believe the water is safe to drink.

"There is no evidence of water contamination," Turner said.

Workers collected two sets of water samples early Monday and delivered them to a lab for processing. The samples must sit for 18 hours for a full all-clear, Turner said.

Children, seniors vulnerable to bacteria 

The public was advised to bring water to a boil for at least two minutes – then letting it cool – before using it for drinking, cooking, bathing and brushing teeth. Children, seniors and people with weakened immune systems are particularly vulnerable to harmful bacteria, but all water customers were advised to follow those directions, the city said in a statement.

Water for icemakers and water dispensers from refrigerators should not be used until the water is declared safe, the city said.

MISSISSIPPI WATER CRISIS: Jackson water issues flow from a century of poverty, neglect and racism

District closes schools for 210,000 students

Gov. Greg Abbott said his office had been in contact with Turner to offer support. Abbott's office was working to fulfill the city's request for help with a rapid turnaround of water sample results, Abbot said.

"Together, we will ensure our fellow Texans are supported while the city's water supply returns," Abbott said.

The Houston Independent School District extended the Thanksgiving break at least one day, closing schools for its more than 210,000 students and almost 12,000 teachers.

The district said it "will closely monitor the situation and provide additional updates regarding operations."

This article originally appeared on USA TODAY: Houston issues boil water advisory to over 2 million, closes schools