According to the WHO, tap water is safe for consumption for 100% of the country.
According to the CDC tap water is generally not safe for consumption.
According to the Numbeo water drinkability and accessibility index, tap water has a score of 52.27 / 100 (100 being best).
Numbeo considers this score to be "Moderate"
1 adult could save about 1701$ per year in Guam by drinking tap water instead of buying bottled water.
๐ณ Drinking tap water would also help with reducing your plastic footprint and improve environmental pollution.
