What we know about Houston’s water boil order

KPRC 2 knows many of you are asking questions about what happened Sunday that caused the entire city to face a boil water order that’s impacting homes, businesses, and schools.

Houston city officials offered an update on the water boil notice at 10:30 a.m. Monday. This is what they said about the situation:

What triggered the water boil order?

“At 10:30 a.m. Sunday morning, the East Water Purification Plants one and two lost power,” Houston Mayor Sylvester Turner said in a news conference Monday. “At 10:50 a.m. plant three lost power. And these are the three plants located inside the East Water Purification Plant. Just before 11 a.m. the water pressure dipped below the regulatory levels of 35 PSI at 21 water pressure monitoring sites. At 11 a.m. pressure at 16 of those 21 sites dropped below the emergency regulatory level of 20 PSI. Pressure rebounded above 20 PSI in less than two minutes at 14 of the 16 locations. The remaining two locations rose above 20 PSI at 11:30 a.m. So 14 were below 20 PSI for less than two minutes. Two of the sensors rebounded above 20 PSI in thirty minutes. Five of the 21 sensors never fell below 20 PSI.”

What caused the power outage?

“A plant electrician arrived at the East Water Purification Plant at 11 a.m. to troubleshoot the problem,” Turner said. “Further investigation by Houston Water found that two transformers at plant one went offline due to a ground trip and current overload. The electrical feeder from plant three also experienced a ground fault trip. Both Saber, the electrical contractor, and CenterPoint Energy were on site to investigation how not one transformer faulted but the redundant transformer also failed.”

Why didn’t the generators kick in as soon as the power went out?

“What I’m being told is even when you have the grid providing power and you have your generators to step in, when these two transformers fail it prevented the power to the system,” Turner said.

How long was the power out?

“Power was restored to plants one and two at 12:15 p.m. Sunday and power was restored to plant three at 12:30 p.m.,” Turner said. “So in terms of the power disruption, two hours, from 10:30 a.m. to 12:30 p.m.”

Why was the water boil order issued Sunday evening?

“Houston Water in communication with TCEQ (Texas Commission on Environmental Quality) determined a boil water notice needed to be issued on Sunday evening and that was somewhere around 6 p.m., 6:40 p.m. when that decision was made,” Turner said. “Conversations with TCEQ were taking place from 2:43 p.m. up to 6:40 p.m. and it was at that point, based on the data, based on the sensors that a decision was made that a boil water notice was to be issued. One of the reasons why it took that long was because 14 of the sensors remained below 20 PSI for less than two minutes and for two sensors they remained below 20 PSI for 30 minutes. So there were questions as to whether or not a boil water notice even needed to be issued. A decision was made out of an abundance caution to issue the boil water notice and the notice was sent the public at 6:44 p.m. Sunday night.”

What happens now?

“The TCEQ approved our water sampling plan at 10:41 p.m. Sunday night,” Turner said. “Samples were pulled from 29 locations at 6 a.m. and 9:30 a.m. this morning. All the samples arrived at Houston Water labs by 9:45 a.m. this morning. The samples will then sit and incubate for at least 18 hours per state regulations. And the first reads of the samples will be taken at 3 a.m. [Tuesday] to determine if the water is free from contamination. Those results will be sent to the TCEQ for verification and to determine if the city can rescind the boil water notice.”

“We are optimistic the results will come back clean.”

Answers to other boil water notice questions

The City of Houston sent out answers to other frequently asked questions about boil water orders. You should be using boiled water for everything including brushing teeth, cleaning produce, making baby formula or drinks. Throw out ice that might have been made before the boil water notice was issued.

If you have an in-home water treatment system, you may want to boil that water just in case. Using a water filtration pitcher is not a suitable substitute for boiling the water. Read over the entire FAQ list here.

While the concern over the water supply may be alleviated within a day or two, some of the responses available have led to additional questions. The KPRC 2 team, including KPRC 2 Investigates, will follow up with local leaders and industry experts and provide updates as we get them.