Technical Abstract: Grape growers in some regions of California are confronting problems with soil salinity. Improving irrigation water quality at the source well offers a potential solution to mitigate soil salinity issues in vineyards. Here, we utilized tracer-pulse technology and chemical analysis to assess flow and constituent contributions at numerous points throughout the depth profiles of three wells with known salinity problems. Theoretical well manipulation effects were then calculated to evaluate whether blocking inflow at each layer of each well’s depth profile would improve overall water quality at the surface. At the surface, all three wells had several chemical constituents measuring at concentrations higher than recommended threshold for grapevines. The profiling technology effectively measured variation in flow and chemical contributions along each profile. As no strong chemical hotspots were detected and the distributions were relatively uniform/symmetric across each of the depth profiles, the theoretical well manipulation offered little improvement in overall well water quality without detrimental effects on volume pumping capacity. For example, in one well a manipulation inserted at 73-113m below ground surface would reduce the overall concentration of several constituents of concern, but would be accompanied by a 41% reduction in well flow. While a well manipulation would have minimal effect for the three wells assessed in this study, this method could be an effective means of improving irrigation water quality for wells with stronger asymmetrical patterns of constituent contributions.