Nearly all of the surface water entering the District is conveyed through the California Aqueduct of the State Water Project (SWP). About once per month, the DWR collects grab samples from various points on the Aqueduct and analyzes them for general minerals, general physical characteristics, and metals. The sampling point most reflective of District water quality is the State’s John R. Teerink Pumping Plant, located roughly 4.5 miles downstream from the Aqueduct crossing at Highway 166.
Once per week, the District collects a piped water sample at its headquarters on Highway 166 to help provide an indication of the amount of coliform bacteria in the California Aqueduct. These weekly bacteria samples are only representative of one arbitrary point in the District’s WRM 8 System and are not intended to suggest fitness for human consumption nor to represent bacterial levels at all points in the Districts 300-mile piped system. Customers who need to know bacteria levels in their process water, wash water, or irrigation water for compliance purposes should collect their own samples downstream from their meter.
For links to historical water quality data, click here.