Stable isotopic analysis of water use patterns in wetland vegetation can provide insight into the anticipated ecophysiological response of individual species to seasonal and/or episodic changes in water quality such as saltwater incursion into freshwater wetland ecosystems. In this study, variation in water source utilization over the course of a growing season was investigated in Taxodium distichum (baldcypress), a foundational species in both naturally occurring wetlands and regional wetland restoration projects in the southeastern United States. Over the course of the 2014 growing season, water use patterns were monitored in three baldcypress stands at the Timberlake Observatory for Wetland Restoration (TOWeR) in Tyrrell County, North Carolina, by comparing the isotopic composition (δ²H and δ¹⁸O) of xylem water extracted from plant tissue to that of the available water sources: surface water, sediment porewater, groundwater sampled from multiple locations in the region, and rainwater. Results indicate that water sources that are impacted by periodic saltwater incursion may be utilized by baldcypress at TOWeR, but the short-term health and reproductive competency of baldcypress at the site has not been negatively impacted by seasonal, episodic, surface water salinity incursions at the site.