Updated 7:26 a.m. Nov. 29

The city of Houston lifted its boil-water notice, according to an alert sent out by the city in the early morning of Nov. 29.

The update came after water quality tests by the Texas Commission on Environmental Quality confirmed that tap water met all state regulatory standards and was safe to drink, according to the city. The tests involved analyzing 29 water systems throughout the city.

Water customers are being advised to flush their water systems by running cold water faucets for at least one minute. Customers should also run water softeners through a regeneration cycle and clear automatic ice makers by making and discarding several batches of ice.

Updated 10:30 p.m. Nov. 28

The water-boil notice remains ongoing in the city of Houston, and Houston ISD officials have announced classes have been canceled for Nov. 29.

Classes were canceled in part because HISD would not be able to provide meals or safe water for students, officials said. District employees will work remotely unless otherwise instructed.

A decision on whether classes will be held Nov. 30 will be made following pending updates from the city of Houston on the boil water notice. Houston Mayor Sylvester Turner previously said he hoped to know more the evening of Nov. 28 or morning of Nov. 29, after water samples were tested.

A map of where the boil-water notice is in effect can be found here.

Posted 12 p.m. Nov. 28

The city of Houston issued a boil-water order Nov. 27 that remains in effect Nov. 28 and covers the bulk of the city's limits. Meanwhile, other cities and water providers that get their water from Houston's main system have issued their own notices out of an abundance of caution.

The notice was issued after water pressure dropped below the state’s minimum requirement during a power outage at the city's East Water Purification Plant at 10:30 a.m. Nov. 27.

The loss of power was attributed to two unique transformer failures, Houston Mayor Sylvester Turner said at a Nov. 28 news conference. The power failure was internal and was related to a backup transformer and a primary transformer at the plant, but power to the plant remained via a generator, Turner said.

By 11 a.m. Nov. 27, water pressure dropped in 16 locations at the plant, but 14 rebounded within two minutes, Turner said. The other two reached the normal levels after 30 minutes, he said.

Power was restored to the plant by 12:30 p.m. Nov. 27, and full water pressure was restored by 3:30 p.m.

When the pressure falls below the minimum, it allows for possible pollutants to enter the water, city officials said. However, this did not happen during the outage, according to Public Works Director Carol Haddock. Haddock said there was no indication of any "intrusions" into the water.

The boil-water notice was issued at 6:40 p.m. Nov. 27 by the city of Houston and the Texas Commission on Environmental Quality out of “an abundance of caution,” Turner said during the Nov. 28 conference.

A press release by Houston Public Works instructed residents in certain areas that receive water from the city to follow guidance from their local jurisdictions, including the cities of Bellaire, Friendswood, Humble,Jersey Village, Pearland, Southside Place and West University Place, among others.

West University Place said only residents living on Law Street are affected. City officials announced Nov. 27 they had shut off water intake from Houston and are monitoring levels. Meanwhile residents are asked to take water conservation measures.

Bellaire announced Nov. 27 it had issued a boil-water notice "out of an abundance of caution" and is working to isolate its water system.

Houstonians should boil water for bathing, consumption and brushing teeth to eliminate the possibility of ingesting harmful bacteria until the notice is lifted. Individuals who are unable to boil water are advised to purchase packaged water bottles. The city will also provide water to those in need, Turner said.

Samples of water have been taken and are in an incubation stage and will be read at 3 a.m. to determine when the boil-water notice can be rescinded, officials said.

In a Nov. 28 press release, Turner apologized for the disruptions caused by the boil-water notice and noted the city has 24 hours after an outage to issue a boil-water notice. He said he hopes the answer of when the notice can be lifted will be reached by the evening of Nov. 28 or morning of Nov. 29.

Gov. Greg Abbott directed Texas Division of Emergency Management and the TCEQ to aid Houston with any necessary resources in light of the outage.

The East Water Purification Plan provides water to the entire city of Houston and some adjacent areas with the exception of Clear Lake and Kingswood.

Haddock echoed the importance of residents registering for emergency updates from Alert Houston. Turner said he has reached out to public works, calling for a third-party diagnostic review of the outage as a way to prevent future outages.