Heavy Rain Storm of March 2025

During the heavy rainstorm of March 2025, Cameron County experienced power outages throughout.

Included in locations with power outages was the Harlingen Wastewater Plant.

Due to power outage, the HWWS was unable to completely treat all of the wastewater going through the plant and for that reason released 633,000 gallons into the Arroyo Colorado.

However, the effluent was chlorinated to remove pathogens and then de-chlorinated to be able to release.

What was missing in the treatment process was to add oxygen to the effluent.

The plant processed approximately 24 million gallons that day, which is 5 times normal, so the amount that was not treated had a large volume of rainwater for dilution.

As required, TCEQ was notified.