In February 2014, a coal ash spill on Duke Energy's Dan River Plant in Eden, NC released approximately 39,000 tons of coal ash into the Dan River. It took approximately one week to stop the spill. Starting in February 2015, drinking water utilities using the Dan River experienced a series of taste and odor (TandO) events described as "earthy" or "musty". Similar TandO events were not documented before the coal ash spill. This research attempted to understand causes of the TandO events and if the coal ash spill was connected. A variety of water quality analyses were performed on twelve sites from August 2016 to September 2017 on the Dan and Smith Rivers. The Smith River served as the control. From concentrations of coal ash indicators (particularly Ba, Sr, As, V, and Br-), there was a signature of coal ash on the Dan River that was not present on the Smith River. The signature could not be attributed to the coal ash spill, as the signature was present upstream of the spill. Chronic ecosystem toxicity due to metals was low and not significantly different between the Dan and Smith Rivers. No substantial TandO events occurred during the period of this study. All monitored odorants were detected with varying frequencies in both the Dan and Smith Rivers. No significant change in odorant concentration was found above and below the location of the coal ash spill. / MS / In February 2014, a coal ash spill from Duke Energy’s Dan River Plant in Eden, NC released approximately 39,000 tons of coal ash into the Dan River. Starting in February 2015, drinking water utilities using the Dan River experienced a series of taste and odor (T&O) events described as smelling “earthy” or “musty”. Similar T&O events were not documented before the coal ash spill. This research attempted to understand underlying causes of these T&O events and to determine if the coal ash spill was connected. Analyses, including concentrations of coal ash indicators and odorants, were performed from August 2016 to September 2017 on a monthly basis for both the Dan and Smith Rivers. The Smith River served as a control river as it was not impacted by coal burning power plants and or a coal ash spill. There was a signature of coal ash metal contamination in the Dan River but not in the Smith River. The coal ash signature could not be attributed to the 2014 Duke Energy coal ash spill in Eden, NC because it was also found upstream of the area sampled and the location of the coal ash spill. Chronic ecosystem toxicity due to metals was low on the both the Dan and Smith Rivers and was not different between the rivers. No substantial drinking water taste and odor events occurred during the study period. All monitored earth-musty odorants were detected with varying frequency at concentrations mostly below and sometimes above their individual odor threshold concentration.