The California Office of Environmental Health Hazard Assessment has issued a safety advisory for any fish caught in Castaic Lake and Castaic Lagoon due to elevated levels of mercury and PCBs.

[3][4] The 320,000 acre⋅ft (390,000,000 m3) lake, with a surface elevation of approximately 1,500 feet (460 m) above sea level, is the terminus of the West Branch California Aqueduct, though some of its water comes from the 154-square-mile (400 km2) Castaic Creek watershed above the dam.

Water from the lake is distributed throughout the northern portion of the Greater Los Angeles Area.

[7] Castaic Lake was one of the main filming locations for the Mighty Morphin Power Rangers series.

The lake also served as the main filming location for the music video of Sabrina Carpenter's 2024 hit single "Espresso".