Can You Drink Tap Water in Zanzibar?

Tap water in Zanzibar is not safe to drink and this applies throughout the entire archipelago — Stone Town (Mji Mkongwe), the UNESCO World Heritage historic capital of the main island of Unguja, the beach resort areas of Nungwi and Kendwa in the north, Paje, Jambiani, and Bwejuu on the east coast, Matemwe in the northeast, and the outer island of Pemba. Water supply in Zanzibar is managed by the Zanzibar Water Authority (ZAWA), which draws primarily from the coral limestone aquifer system that underlies the main island of Unguja. This aquifer, which forms within the porous coralline limestone geology of the island, is the primary freshwater source for a population of approximately 1.8 million people across the archipelago. Treatment at ZAWA's facilities is limited by the authority's infrastructure constraints, and the water distributed through Zanzibar's pipe network does not meet international drinking water standards at the point of consumption.

Zanzibar's water supply faces several compounding challenges. The coral limestone aquifer that supplies the island is vulnerable to saltwater intrusion along the coastline — a phenomenon that has worsened as population growth and increased extraction have drawn the freshwater lens down, allowing seawater to encroach from the surrounding Indian Ocean. In coastal resort areas including Nungwi, Kendwa, and parts of the Paje beach strip, the water can have a detectably brackish or salty character from this intrusion. Stone Town's distribution network, which serves the historic city's labyrinthine streets of Swahili architecture, Arab merchant houses, and the famous carved wooden doors, includes colonial-era pipe infrastructure that is aging and subject to the same maintenance challenges as other east African urban water systems. Intermittent supply is common throughout both Stone Town and surrounding areas, with many buildings relying on rooftop tanks and cisterns that introduce further quality variability.

The practical result is that no Zanzibar hotel, guesthouse, or restaurant of any category presents tap water as a drinking option. Beach resorts across Nungwi — including the established hotel properties along the northern tip — and the boutique properties of Kendwa, Paje, and Matemwe all provide sealed bottled water for guests and use purified or filtered water for all food preparation and ice production. In Stone Town, which has a thriving food scene centred on the famous Forodhani Night Food Market at the waterfront and the Old Fort, all established restaurants use purified water for cooking and beverages. The night market's grilled seafood — one of Zanzibar's most celebrated culinary experiences — is prepared using fire heat sufficient to address biological risks in the food, but visitors should avoid drinking anything made with tap water at any market stall and carry their own sealed bottled water to the evening market.

Zanzibar's tourism circuit involves extensive movement between the main island and surrounding sites. Day trips from Stone Town or beach resorts to Prison Island (Changuu Island) — home to the famous giant Aldabra tortoises — the Jozani Chwaka Bay National Park (habitat of the endemic red colobus monkey), the spice farm tours of the island's interior, and boat trips to the Mnemba Atoll marine reserve for snorkelling all involve extended time away from resort water supplies. Carrying sufficient sealed bottled water for the full duration of any excursion is essential. Water availability at national park sites, spice farms, and boat excursion stops is unreliable, and the equatorial heat and humidity of Zanzibar — year-round temperatures of 25–32°C with high coastal humidity — make adequate hydration from safe sealed sources a genuine health priority throughout any active day.

For visitors combining Zanzibar with a Tanzania mainland safari itinerary — flying from Zanzibar's Abeid Amani Karume International Airport to the Serengeti, Ngorongoro Crater, or Selous Game Reserve — the same water safety approach applies throughout Tanzania. On safari, all reputable camps and lodges provide sealed bottled or filtered water for guests. The Kilimanjaro brand is available throughout Tanzania and is the most reliable indicator of a locally trusted safe water source. Never consume water from any natural source — including the apparently pristine streams of the Serengeti or the crater floor of Ngorongoro — regardless of appearance.