Pulgas Water Temple, Monument near Crystal Springs Reservoir, United States

Pulgas Water Temple is a monument in California near Crystal Springs Reservoir, designed with a ring of Corinthian columns arranged in a circle around a central vault. A masonry ring at the top of the structure bears an inscription from Isaiah 43:20, while the overall design of the building merges Greek Revival architecture with Roman influences.

In 1934, this structure was built to celebrate the completion of the Hetch Hetchy Aqueduct, which carried water over 160 miles (257 kilometers) from the Sierra Nevada to San Francisco. The project brought a new water supply to the city and changed the region through infrastructure for storage and distribution.

The name comes from Rancho de las Pulgas, the Spanish land grant covering this area; pulgas is Spanish for "fleas", a translation of a word for vermin in the name of Cachanigtac, the Lamchin Ohlone village. Carver Albert Bernasconi cut the Corinthian capitals and the shell and scroll motifs of the dome to William Merchant's design.

The temple stands at the terminus of the Hetch Hetchy Aqueduct, with a reflecting pool lined by cypress trees in front of it. The well inside the temple is covered by a grate, so visitors look down into it rather than over a waterfall. The site also holds California Historical Landmark No. 92, marking the Portolá expedition camp of November 11, 1769.

Water no longer flows through the central vault since 2004, as the system was rerouted to remove chloramine at a nearby facility before entering Crystal Springs Reservoir. The original function as the endpoint of the aqueduct was abandoned, and the structure now serves solely as a memorial site.