We sought to determine the degree to which Clean Water Act (CWA) National Pollutant Discharge Elimination System (NPDES) memoranda of agreement (MOAs) between the U.S. Environmental Protection Agency (EPA) and States comply with federal requirements, and whether MOAs impede EPA's ability to exercise consistent management controls and oversight of State enforcement activities. Past reviews by the EPA Office of Inspector General (OIG) and others identified widespread enforcement problems. Although there are many causes for this common pattern of noncompliance, the EPA Office of Enforcement and Compliance Assurance (OECA) identified poor quality MOAs between EPA and States as one impediment to consistent enforcement. OECA requested that the EPA OIG evaluate the issue. This evaluation is part of a series of OIG reviews of EPA oversight of State enforcement programs.