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About Us


Everyday, we have you in mind as we take care and manage the underground water supply all of us in the San Gabriel Valley rely on. About 80% of the water you depend on comes from this one amazing water supply source, deep down underground — the Main San Gabriel Groundwater Basin. In 1973, we were created by the Los Angeles County Superior Court; our official name is the Main San Gabriel Basin Watermaster.

We are sharing the story of our underground water because all of us in the San Gabriel Valley have a role in its care, including you, your family and friends. Please help us share this story, the story of the waters that connect us.

Learn more about us at

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