Residents in parts of the Guam Waterworks Authority’s Northern System are under a boil water advisory after tests detected fecal coliform and Escherichia coli bacteria in the water supply on Dec. 1, 2025. Officials warned that the contamination poses a health risk, particularly for infants, young children and people with weakened immune systems.
GWA advised customers not to drink tap water without boiling it first. All water should be brought to a rolling boil for three minutes, then cooled before use. Boiled or bottled water should be used for drinking, making ice, brushing teeth, washing dishes and food preparation until further notice. Officials said boiling kills bacteria and other harmful organisms.
Fecal coliforms and E. coli indicate possible contamination from human or animal waste. Exposure can cause diarrhea, cramps, nausea, headaches and other symptoms. Health officials noted that these symptoms are not caused only by drinking water and urged anyone experiencing persistent illness to seek medical advice, especially those at higher risk.
GWA said it is conducting a Level 2 Assessment to identify the source of the contamination. The system has been flushed, with chlorine levels and water pressure confirmed to be within acceptable ranges. Most resampling results have come back clear, with one exception, and the identified source has been resolved but may not yet be fully cleared from the system. Affected areas include parts of Chalan Pago, Ordot, Yona and surrounding neighborhoods. Customers will be notified when testing confirms the water is safe to drink again.