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Watersheds
A watershed is an area of land that drains water into a lake or river. Everything that is on the land, whether a natural feature or a human activity, is part of the watershed. Each of us lives, works or plays in watersheds.
The Public Utilities Department operates nine water supply reservoirs (commonly referred to as City lakes) throughout San Diego County. These reservoirs capture runoff from rainfall and also store water imported from hundreds of miles away. Our reservoirs are critical components of the regional water supply system as water is supplied to nearly 2 million people in the City of San Diego and neighboring communities.
Protecting water sources is vital to providing healthy and safe drinking water to all of our customers. We have a commitment to environmental protection because our watersheds and reservoirs have multiple uses such as drinking water, irrigation, recreation, wildlife food and shelter. What we do in our everyday lives can have an effect on watersheds, reservoirs and the quality of our drinking water. The 
Watershed Map shows the areas that affect the City's reservoirs.
Source Water Protection Guidelines
The Source Water Protection Guidelines are aimed at protecting our local source waters from the effects of new residential and commercial development in the watersheds. Overall, the Guidelines serve as a road map for sensible development, increase the reliability of the water supply system and reduce the cost of drinking water treatment.
Watershed Sanitary Survey
Learn about the potential sources of contaminants in the watersheds draining to the City's reservoirs and the recommendations for managing these effects.
Pesticides and Herbicides
The "How Your Pesticides and Herbicides Can Affect Water Quality" brochure provides information about limiting contamination by keeping pesticides, herbicides and irrigation runoff out of our waterways and source waters.
Watersheds Display Boards
Look for special display boards at City reservoirs and learn how the Public Utilities Department protects our watersheds and how you can help prevent pollution and contaminants from getting into our drinking water.
Hodges Reservoir Hypolimnetic Oxygenation System
A hypolimnetic oxygenation system oxygenates the bottom waters to reduce internal nutrient cycling and control excessive algal productivity in Hodges Reservoir to improve water quality. For more details, please visit: