Houston under boil water order after treatment plant failure

Authorities in the US city of Houston ordered residents to boil their water before drinking it after a power outage at a treatment plant, leaving classes and other activities cancelled Monday.

Houston, the biggest city in Texas and the fourth-largest in the United States, is home to 2.2 million people and is an important base for the energy, aeronautics and healthcare industries.

"A boil water notice has been issued for the City of Houston," the municipality posted on Twitter Sunday night.

"Everyone should boil the water before drinking, cooking, bathing, and brushing their teeth," the city's account said.

A power outage at three purification plants Sunday led to a drop in water pressure below the threshold allowed by the Texas Commission on Environmental Quality (TCEQ), Governor Greg Abbott's office said, triggering the boil water notice and requiring safety testing of the city's water supply.

The cause and duration of the power outage are still under investigation, local officials said.

Following the order, Houston Independent School District said "schools, offices and facilities" were closed Monday, though several nearby suburban districts said most or all of their schools were unaffected and remained open.

The office of Houston Mayor Sylvester Turner said in a tweet they "believe the water is safe but based on regulatory requirements when the pressure drops below 20 psi we are obligated to issue a boil water notice."

The TCEQ planned to sample and test water throughout the day Monday to determine whether the boil order could be lifted by Monday night or Tuesday morning, Turner's office said.

"The State of Texas is immediately responding and deploying support to Houston as they work to get a safe supply of water back online," Abbott said Sunday night.

The boil order comes after a winter storm and subsequent cold spell in February 2021 saw pipes burst throughout Texas and left much of the state of nearly 30 million people without potable water for several days.

The fellow southern US city of Jackson, Mississippi was without safe drinking water for several weeks earlier this year when floods disrupted operations at a critical treatment plant.