N-Nitrosodimethylamine (NDMA) is a trace carcinogenic byproduct of chlorination in treated wastewater effluents. NDMA is readily miscible in water and does not adsorb to soil, and therefore may pose a threat for groundwater contamination when treated wastewater is used for irrigation. A field study was carried out to evaluate the leaching potential of NDMA when treated wastewater was used for irrigating turfgrass plots. Treated wastewater from a local treatment plant was substituted for irrigation water at 110-160% ETo for about 4 months, and leachate from the irrigated plots was continuously collected and analyzed for NDMA. The treated wastewater contained high levels of NDMA (114-1818 ng/L; mean 930 ng/L). However, essentially no NDMA was detected in the leachate regardless the soil type or irrigation schedule. At a method detection limit of 2 ng/L, only 10 out of 400, or 2.5%, of the leachate samples showed positive detection of NDMA at 2-5 ng/L. These results were corroborated with analysis performed independently by two external laboratories. NDMA was found to be moderately persistent in turfgrass soils during laboratory incubation, indicating that other mechanisms, likely volatilization and/or plant uptake, contributed to the rapid dissipation. As the field study was conducted under “worst case” scenario, it may be concluded that irrigation with wastewater will unlikely cause groundwater contamination by NDMA under commonly occurring conditions.