Alcatraz Water Tower

The Alcatraz Water Tower is a concrete structure that rises roughly 94 feet above the island and housed a large storage tank for drinking water. This facility was an essential part of the prison complex's infrastructure and remains standing on the grounds today.

The tower was built between 1940 and 1941 by the Federal Bureau of Prisons to supply water to the maximum-security penitentiary. After the prison closed in 1963, the structure was preserved and eventually protected as part of the island's historical site.

Activists left painted messages of freedom and protest on the tower during the Native American occupation from 1969 to 1971, and these marks remain visible today. The structure became a symbol of resistance and self-determination during this pivotal moment in history.

The tower is visible from outside but closed to public entry as it sits on protected grounds within the national monument. Visitors can photograph it from designated viewing areas while following the marked paths throughout the island.

The island had no natural freshwater supply, so water was delivered twice weekly by boat from San Francisco to fill the tower. This isolation made keeping the prison supplied with drinking water an ongoing logistical challenge.

Location: San Francisco

GPS coordinates: 37.82750,-122.42389

Latest update: December 12, 2025 09:01