Phenylurea pesticides that were introduced worldwide in the 1950s are used commercially on a wide range of food crops. Subsequently determined to possess a significant toxicological risk, the agricultural runoff of these compounds may be found in drinking water supplies. The United States Environmental Protection Agency (US EPA) requires that drinking water and raw surface water be monitored for the presence of Phenylurea pesticides and related compounds using EPA Method 532.0. The European Union (EU) regulation regarding drinking water (EC Directive 98/83/EC), provides a general rule for pesticides and metabolites. This regulation limits the maximum admissible concentration (MAC) at 0.1 ppb for each individual component, with the total concentration not to exceed 0.5 ppb.