Salinization is increasingly affecting many watersheds, significantly impacting drinking water resources and infrastructure, reducing stability and resilience of aquatic ecosystems, and potentially hindering stream and river restoration efforts. Salinization is related to deicer use on roadways with additional contributions from accelerated weathering of impervious surfaces, water softeners, and sewage. The concentrations of chloride observed in many urban streams in Maryland now exceed the limit of 250 mg/L established by the U.S. EPA for chronic toxicity to freshwater life. These observed ranges and extreme fluctuations in salinity can mobilize nitrogen, phosphorus, base cations, and toxic metals from sediments to streams due to enhanced ion exchange and solubility.