Bean Hollow #2, also known as De Los Frijoles Reservoir, is a privately owned dam located in San Mateo, California. This earth dam was completed in 1938 and serves primarily for water supply purposes, including irrigation. The reservoir has a storage capacity of 900 acre-feet and covers a surface area of 43 acres, with a drainage area of 1.38 square miles along the Ar De Los Frijoles stream.

With a dam height of 31 feet and a hydraulic height of 26 feet, Bean Hollow #2 has a low hazard potential and is considered to be in satisfactory condition as of the last assessment in September 2017. The dam is regulated and inspected by the California Department of Water Resources (DWR) under the Safety of Dams program. The last inspection was conducted in February 2020, with a frequency of one inspection per year to ensure the safety and integrity of the structure.

Located near the Pacific Ocean, Bean Hollow #2 plays a crucial role in providing water supply for the surrounding area. With its historical significance dating back to the late 1930s, this reservoir continues to be a vital resource for the community while also maintaining a low risk profile and meeting regulatory guidelines set forth by the state.