No matter where you live — and how much or how little water you see nearby — you live in a watershed. A watershed is all of the land that drains to the same location or body of water, such as a river, lake, reservoir, bay, or ocean. In the Los Angeles region, watersheds connect mountains, neighborhoods, streets, storm drains, rivers, beaches, habitats, and communities.
A Watershed Is More Than a River
A watershed includes the land, waterways, storm drains, groundwater, parks, streets, buildings, and open spaces that influence where water goes after it rains.
When rain falls, it may soak into the ground, collect in soil and groundwater, flow across streets and landscapes, or move through creeks, storm drains, channels, and rivers. What happens on the land affects the water that moves through the watershed.
Rain Falls
Water lands on rooftops, streets, landscapes, parks, mountains, and open spaces.
Water Moves
Some water soaks into the ground, while some flows across surfaces into storm drains, creeks, rivers, and channels.
Everything Connects
Water eventually reaches shared destinations like rivers, groundwater, reservoirs, bays, or the ocean.
Why Watersheds Matter
Healthy watersheds support clean water, habitat, local water supply, climate resilience, and the well-being of communities.
Clean Water
Land use, pollution, stormwater, and runoff all affect the quality of water moving through a watershed.
Flooding and Stormwater
Watersheds shape how rainwater moves, where flooding can happen, and how communities can manage stormwater.
Habitat and Wildlife
Rivers, streams, wetlands, and riparian areas provide habitat for plants, animals, and connected ecosystems.
Community Health
Watershed planning can support parks, shade, cooling, access to nature, and healthier neighborhoods.
Watersheds in the Los Angeles Region
The Los Angeles region includes many connected watersheds, each with its own rivers, streams, neighborhoods, habitats, infrastructure, and challenges.
CWH’s work focuses on helping communities and partners better understand these systems so they can protect water quality, restore habitat, improve resilience, and plan for healthier watershed futures.
Los Angeles watershed map placeholder
Explore Your Watershed
Want to learn more about the waterway near you? Use EPA’s How’s My Waterway tool to explore local water information and better understand the watershed you live in.
Keep Learning
Resource Library
Browse CWH reports, maps, educational materials, recordings, publications, and other watershed resources.
Water 101 Library
Start with foundational watershed, water, and community education resources.
River Resources
Explore resources focused on rivers, streams, and watershed education.