HOUSTON (AP) — Houston officials on Tuesday lifted an order requiring more than 2 million people in the nation’s fourth-largest city to boil their tap water before drinking or using it.

The boil order had been in place since Sunday, when a power outage at a purification plant caused a drop in pressure.

The order led to the closure of businesses and schools, including the Houston Independent School District, which canceled classes Monday and Tuesday. The city rescinded the order shortly before 7 a.m. Tuesday.

The city said water quality samples submitted to the Texas Commission on Environmental Quality confirmed that the tap water meets regulatory standards and is safe to drink.

At a press conference Monday, Mayor Sylvester Turner said the city issued the advisory, which affects all of Houston and some adjacent areas, out of an «extreme amount of caution» after two transformers, one main and its backup, failed.» uniquely and coincidentally». in a water plant. The problem affected the plant’s ability to treat and pump water to the transmission system, causing low pressure.

Because the problem was within the plant’s system, backup power generators would not have made a difference, Turner said. Since the transformers were not working, they could not transmit power to the plant.

The power system at the water plant undergoes regular maintenance, Turner said, but he did not give a schedule of how often. The mayor said he ordered a diagnostic check of the system to understand how the problem was possible and how it can be prevented.

Sixteen sensors reported drops below the minimum pressure levels required by the Texas Commission on Environmental Quality, 14 of them for just 2 minutes and two for nearly 30 minutes, Turner said.

Usually there is enough pressure for water to flow out of leaky pipes. However, when pressure is lost, contamination such as bacteria found near the pipes can be sucked into the system, creating a health risk.