Long-term analysis of road salt loading and transport in a rural drinking water reservoir watershed

•Road salt loading and transport analyzed for a twenty-year period of study.•Mass balance reveals chloride accumulation in a pristine drinking water reservoir.•74% of the watershed chloride load was delivered through baseflow.•Chloride concentrations in tributary baseflow exceeded those in runoff.•High reservoir CSMR levels indicate potential risk for lead-based corrosion.