Irrigation of crops with treated wastewater has been employed in many regions of the world. It mitigates the pressure of water demand, however, it also introduces effluent-derived organic contaminants into surface waters via agricultural runoff. In this study, a potato field located in southern California was selected as the research site. Runoff samples were collected during irrigation events, and a variety of compounds were identified both in irrigation water and runoff samples. Treatments on the field included polyacrylamide (PAM) application, deep plow, previous-grown Sudan grass, and control (without above treatments). The compounds included pharmaceuticals (e.g., clofibric acid, ibuprofen, naproxen, ketoprofen, diclofenac), personal care product (e.g., triclosan), endocrine disrupting compounds (e.g., bisphenol A, 4-n-nonylphenol, 4-t-octylphenol), and estrogenic compounds (e.g., estrone, 17β-estradiol, 17α-ethynylestradiol). Themonitoring results showed the presence of these compounds in runoff samples. They were at concentrations from below limits of quantification (LOQ) to sub μg/l levels. Although their levels were low, their potential to elicit adverse effects in aquatic organisms cannot be overlooked.