There are multiple agencies responsible or overseeing water quality for residents in the West San Gabriel Valley. The Main San Gabriel Basin Watermaster, is an agency that ensures we don’t use too much water from the basin, while the LA County Department of Public Works oversees the water that is added to our groundwater supplies, such as additional water supply from Northern California as LA County does not have enough local water to meet everyone’s needs. This imported water is piped into the San Gabriel Canyon spreading grounds, which are water conservation facilities that add surface water to the groundwater supplies.