Comparing domestic and public-supply groundwater quality in the northern San Joaquin Valley, 2019—California GAMA Priority Basin Project

Groundwater quality in the Northern San Joaquin Valley region of California was studied as part of California State Water Resources Control Board (SWRCB) Groundwater Ambient Monitoring and Assessment Program-Priority Basin Project (GAMA-PBP). The GAMA-PBP made a spatially unbiased assessment of the aquifer system used for domestic drinking-water supply in the study region and compared the results to the aquifer system used for public drinking-water supply. These assessments characterized the quality of raw groundwater to evaluate ambient conditions in regional aquifers and not the quality of treated drinking water. The study included two components: (1) a status assessment presenting study results summarizing the status of groundwater quality used for domestic supply in the Northern San Joaquin Valley and (2) a comparative assessment of groundwater resources used for domestic and public drinking-water supply in the study region.