Pharmaceuticals have been widely detected in surface waters and groundwaters throughout Europe and the United States. Studies over the last 15 years have shown that a variety of pharmaceuticals, hormonally active agents, and household and industrially used organic wastewater compounds (OWCs) commonly are detected in wastewater effluents. The increase in water reuse in many U.S. States has also lead to concern about the accumulation and potential effects of these compounds . In a recent study by the U.S. Geological Survey, antibiotics from several classes were found in wastewater effluents from six wastewater treatment plants (WWTPs) in five States. Multiple samplings of the influent and effluent from a WWTP showed that many pharmaceuticals and other wastewater contaminants are only partially removed and need to be considered when contemplating subsequent water reuse applications. Another limited study indicated that there was a higher frequency of occurrence of OWCs in effluent from a trickling filter plant than was found in effluent from an activated sludge plant. Data from these and other studies show that many WWTP effluents used for water reuse applications likely will contain a variety of OWCs. A study of the application of reclaimed water used to irrigate municipal properties showed that a variety of pharmaceuticals are transported and accumulate in the soil profile. Thus, OWCs may be available for transport to surface and groundwater following their introduction to the land surface via water reuse applications.