The City of Houston, Texas, issued a boil water notice to 2.2 million water customers after its East Water Purification Plant lost power on the morning of Sunday, Nov. 27, lowering water pressure for the distribution system.
The plant had lost power at 10:30 a.m. causing the city’s water pressure to drop below 20 PSI, the Texas Commission on Environmental Quality’s (TCEQ’s) required minimum. Water pressure was restored shortly after the power outage,
The Houston Independent School District (ISD) announced on Twitter on Sunday that it would close all its schools, offices, and facilities for Monday in response to the notice.
Low pressure can allow backflow in a water distribution system, allowing untreated water to enter the system.
“We believe the water is safe but, based on regulatory requirements when pressure drops below 20 psi, we are obligated to issue a boil water notice,” says the Houston Mayor’s Office.
“Our system maintained pressure; we never lost pressure fully,” Yvonne Williams Forest, director of Houston Water, told KHOU 11 News. “So there was never an opportunity for anything to enter our system. They just fell below the regulatory requirements.”
As part of the regulatory response to the pressure drop, the city submitted a water sampling plan to the TCEQ for approval. On the morning of Monday, Nov. 28, the city announced that TCEQ had approved the plan: workers can begin collecting samples for testing.
According to the Texas Tribune, Houston Public Works spokesperson Erin Jones says that the boil water notice is expected to be lifted Tuesday morning, after the Texas Commission on Environmental Quality reviews the city’s water samples.