Whale Rock Reservoir, located near Cayucos in San Luis Obispo County, is a 38,967 acre-foot reservoir that strictly prohibits all watercraft, including kayaks and canoes. No water contact activities of any kind are permitted, as this is a drinking water supply reservoir for the City of San Luis Obispo, Cal Poly State University, and California Men's Colony.

The reservoir covers approximately 600 acres and was created in 1961 by the construction of an earthen dam on Old Creek. While paddling is not allowed, the reservoir offers other recreational opportunities including bank fishing (seasonal from late April through November 15, Wednesday through Sunday) and hiking along approximately 3 miles of trails with views of the Pacific Ocean, which lies just one mile away.

The facility is open from 6 AM to 7 PM, with an electric gate that closes promptly at 7 PM. Amenities include seven pit toilets and multiple picnic areas. A $2 daily access fee supports maintenance of the public access area. The property encompasses 1,400 acres of open space and is home to diverse wildlife, including three resident bald eagles, osprey, and numerous migratory birds.

For record-keeping purposes, it's worth noting that the reservoir captures water from a 20.3 square mile watershed and features a maximum water elevation of 216 feet. The dam and surrounding infrastructure are maintained by a staff of three who oversee 13 miles of fence line, the dam structure, monitoring instrumentation, two pumping stations, and 18 miles of pipeline.