Water Quality

The history of water in the San Gabriel Valley is ultimately tied to water quality.  The once abundant San Gabriel Valley groundwater basin became over drafted beginning in the 1940s through the 1970s.  This dynamic was led first by agriculture and then by industrial activities in the San Gabriel Valley, as water was drawn from deeper within wells leading to extraction of salt and other minerals.  Water with heavy salt and metal content makes it difficult to grow crops.  Industrial pollution impacted many wells – making it necessary to establish the San Gabriel Valley Water Quality Authority to gather funding and plan projects to clean up contaminants such as perchlorate, and hexavalent chromium.

With over-drafted and contaminated aquifers, Upper District was charged with facilitating the purchase of imported water through the Metropolitan Water District of Southern California (MWD) as well as creating water conservation and watershed stewardship programs.  Imported water has water quality issues of its own.  Higher salinity of Colorado River water and higher nutrients in water from Northern California makes blending and treating water of key importance.  Salt, for example in low levels can be harmful to industrial equipment and home appliances such as hot water heaters.  MWD issues Water quality reports annually as Upper District’s 29 retail customers including city water departments and private utilities do as well.  Protecting water quality for human consumption is the highest priority for all water agencies, as well as the biggest cost driver in water rates.