Guam Waterworks Authority General Manager Miguel Bordallo told Guam mayors that the way the agency handled notifications about the pesticide dieldrin in drinking water fell short of what was needed.
During a Mayors' Council of Guam meeting Wednesday, Bordallo said that although dieldrin is not a federally regulated drinking water contaminant, as of Aug. 1, GWA is required by the Guam Environmental Protection Agency to notify affected customers when levels are above 0.2 parts-per-billion.
The agencies have been aware of dieldrin in Guam groundwater for years, and GEPA has been working on regulations regarding actionable levels of the contaminant. In July, GWA was notified about the new regulations that were to be implemented on Aug. 1.
On Sept. 12, the agency sent notices to 1,112 customers in Yigo letting them know that the termiticide, which was banned in 1987, was found in their water.
The notification was shared widely on social media, raising concerns not only in Yigo, but in villages around the island.
“This method of reporting was insufficient to address the public's concern about the advisory that we sent,” Bordallo said. “So I own that. We failed. We should have done more.”
Bordallo said annual reports on contaminants in the water system are mailed to customers each year, and copies of the reports are available online at the agency’s website.
Since 2023, specific information on dieldrin has been included in the annual water quality reports mailed to GWA customers, he said.
GWA is currently developing a web portal with information about Guam water safety, including historical findings and mapping data. Guam EPA has opened a hotline for information on dieldrin and water safety. Residents can call 671-888-4342 between 7 a.m. and 9 p.m.
Bordallo said nobody knows when or how dieldrin entered the groundwater.
“Apparently, the pesticide was used on Guam, but we don't have any information on where or how long it continued to be used,” he told the mayors. “We understand that the most likely use would be the application to soils before foundations were poured as part of building construction. That's where most termiticides now are used. It's a typical process in construction.”
In a joint news release issued on Sept. 20, GWA and GEPA said areas where dieldrin had been used may “have been disturbed as a result of demolition of older structures, perhaps in relation to new construction and development. This disruption exposes potentially contaminated soil to rainfall – causing dieldrin to percolate into our groundwater sources.”
Bordallo said GWA has been working on a permanent treatment system, which should be in place by the summer of 2026. An interim solution should be in place by mid-October, he said.
“For our part, GWA has been laser-focused on trying to find permanent solutions,” he said. “We didn't put the dieldrin in the groundwater. We don't have any authority to find the source of how it got into the groundwater, but we have been working hard to implement the permanent solutions to remove it.”
After acting Gov. Josh Tenorio declared a state of emergency because of the dieldrin, GWA had access to additional resources to provide bottled water to affected customers, Bordallo said, and he hopes to have deliveries in place within the next week.
“I do want to again emphasize that we recognize that the manner in which we rolled this out, or the advisory was issued, and Guam EPA regulations were rolled out, caused a lot of distress among the affected customers and people in your villages,” he said. “I've been getting inquiries from many of you about whether or not the water is safe, and we are working to get this water safety information site up and running quickly, and that will provide clear, concise and centralized location for all of our current information and progress as our solutions develop.”
