The southern Nottawasaga River Watershed is an area of intensive agriculture where the unconfined surficial groundwater aquifer is known to be impacted by agricultural practices, including high fertilizer application rates. As part of several water quality studies conducted in the Nottawasaga River Watershed in southern Ontario, groundwater samples were collected from private domestic wells, multi-level monitoring wells, and riverbank seeps (i.e., groundwater springs), at various times between 2010 and 2013. Water quality analysis of the samples included parameters measured during sampling (pH, temperature, specific conductivity, dissolved oxygen), general chemistry parameters (e.g., major anions and cations, nutrients) as well as some specialized parameters (water, nitrate, and sulfate isotope ratios, four artificial sweeteners, select herbicides). Information on the analytical methods used and interpretation of the dataset can be found in the following publications: