Is Tap Water Safe to Drink in Cook Islands?

Rarotonga's supply comes from mountain streams captured at intakes and, since the Te Mato Vai project completed major upgrades in the 2020s, is filtered through a modern treatment plant rather than distributed largely untreated as before.

Before Te Mato Vai, Rarotonga's stream-fed supply was linked to periodic gastrointestinal illness from bacterial contamination; treatment has since improved substantially but distribution pipes are still being upgraded island-wide. Outer islands rely on rainwater tanks and groundwater with inconsistent treatment.

Rarotonga, particularly around Avarua and the main resort strip, now has notably better treated water than in the past, though many hotels still recommend bottled water. Outer islands such as Aitutaki, Atiu, and Mangaia depend on rainwater catchment or untreated groundwater wells.

Generally soft, roughly 20–60 mg/L, typical of volcanic mountain-stream sources..

Many Cook Islanders on Rarotonga now drink treated tap water, though boiling or filtering remains common habit, especially on outer islands.

• •Even with upgrades, many hotels on Rarotonga still supply bottled or filtered water as standard practice
• •Carry a portable filter or purification tablets when visiting outer islands
• •Ask your accommodation whether your specific area has been connected to the upgraded Te Mato Vai network

• •Boil or filter water on outer islands where treatment is inconsistent
• •Check with your accommodation on Rarotonga about whether the local pipe network has completed the Te Mato Vai upgrade