Most of American Samoa's main island of Tutuila is now under a boil water notice.
The advisory was issued by the American Samoa Power Authority for all residents living in the area from Iliili to Poloa.
ASPA says its water system detected fecal indicators from ground water sources in the government central water system.
New requirements mean that if a monthly water sample for the main water system is positive for choliform then the source of the water must also be tested.
The rule also requires that a boil water notice be issued which must remain until a plan is in place to fix the problem.