Pulgas is the Spanish word for fleas, which were encountered by early Spanish explorers of the area. In this location, the name comes from the former Rancho de las Pulgas, an early Spanish land grant. The Pulgas Water Temple is commemorated as California State Historical Landmark #92, for being near the camping place of the Spanish Portola expedition on November 11, 1769. Members of the expedition were the first Europeans to explore inland areas of California, and the first to see San Francisco Bay.
Water once flowed to the Pulgas Water Temple and over a small C-shaped waterfall within the temple where it continued approximately 800 feet down a canal to the west into Upper Crystal Springs Reservoir. Starting in 2004, water no longer flows through the temple, but instead is diverted to a nearby treatment plant where chloramine added at the Sunol treatment plant is removed. The treated water is then either sent to Upper Crystal Springs Reservoir via a channel 50 yards west of the water temple, or enters the drinking water system after either being chloraminated yet again at another plant.
Before the temple was closed, 2 billion gallons of Sierra water a year flowed directly through the graceful monument. Visitors could stand beneath the ring of columns and gaze through a large round opening at the madly rushing water below. Now the water does not pass through the temple at all.