Groundwater quality in the Redding–Red Bluff shallow aquifer study unit of the northern Sacramento Valley, California

 This study was designed to provide a statistically representative assessment of the quality of groundwater resources used for domestic drinking water in the Redding– Red Bluff study unit. A total of 50 wells were sampled between December 2018 and April 2019 (Shelton and others, 2020). Domestic wells in the study unit typically are drilled to depths of 80–338 feet (10th–90th percentiles; Shelton and others, 2020), which are shallower (p<0.001) than the depths of public-supply wells in the same area (typically 115–450 feet deep; Bennett and others, 2011). Water levels in domestic wells in the study unit typically are 15–163 feet below land surface (10th–90th percentiles; Shelton and others, 2020).