The San Francisco Watershed (HUC 15040004) covers an area of approximately 304 square miles in northern California. It is primarily fed by snowpack from the Sierra Nevada Mountains, which provides water for the Hetch Hetchy Reservoir. The watershed also includes several smaller reservoirs and streams. The water supply is managed by the San Francisco Public Utilities Commission, which monitors the quality of the water and manages the reservoir's constituents to ensure safe drinking water for the San Francisco Bay Area. Interesting climatic facts include the watershed's location in a Mediterranean climate, with wet winters and dry summers. However, the region has experienced droughts in recent years, leading to decreased snowpack and lower water levels in the reservoirs. Climate change is expected to intensify drought conditions in the future, making the management of the San Francisco Watershed's resources critical for the region's water supply.