The Guam Waterworks Authority (GWA) announced Friday that multiple test results confirm the effectiveness of its Y-15 treatment system in removing dieldrin contamination from the Santa Rosa/Yigo water supply. Following four weeks of testing showing no detection of the pesticide, GWA has formally requested that the Guam Environmental Protection Agency (EPA) rescind its “Do Not Drink Without Treatment” advisory.
According to GWA General Manager Miguel Bordallo, all laboratory analyses of raw and treated water collected on Oct. 11, 16, 23, and 29 showed “non-detect” levels of dieldrin—well below Guam EPA’s interim action level of 0.2 parts per billion. “We have worked diligently to implement corrective actions at Well Y-15, conduct comprehensive testing, and verify that the water is now safe to drink, cook with, and use for bathing,” Bordallo said.
The advisory was issued on Sept. 12 after trace levels of dieldrin were detected at Well Y-15. In response, GWA expedited the installation of a granular activated carbon treatment system, provided bottled water and fill stations, and launched guamwatersafety.com to keep residents informed. The utility also implemented a filtration program for affected homes and businesses.
Residents will be notified through local media, GWA’s social media platforms, and guamwatersafety.com once Guam EPA officially lifts the advisory. For more information, customers may contact GWA Customer Service at (671) 647-7800 or the Guam EPA hotline at (671) 888-4342.