EPA is directed by the Safe Drinking Water Act (SDWA) to annually report on Public Water System (PWS) compliance in the United States. To meet this requirement, EPAs Office of Enforcement and Compliance Assurance (OECA) publishes the National Public Water Systems Compliance Report (Report). The Report for 2010 documents that, while the majority of the U.S. population served by PWSs receives safe drinking water, many systems incurred significant violations of Federal drinking water quality standards. Additionally, EPA and primacy agencies need to work together to improve data quality, which affects EPAs ability to accurately calculate the extent of noncompliance. EPAs new Enforcement Response Policy (ERP) issued on December 8, 2009, establishes a water system-based approach to defining, prioritizing, and addressing noncompliance with Federal requirements. The ERP has been instrumental in improving compliance trends as has been shown in the data. The number of PWSs with significant violations has decreased from 43,203 in 2009 to 39,716 in 2010. Additionally, EPA and primacy agencies need to work together to improve data quality, which affects EPAs ability to accurately quantify the extent of noncompliance. In 2010, there were 153,000 public water systems in the U.S., serving over 317 million users. Small PWSs comprise the vast majority of all systems. Noncompliance occurs more frequently at smaller systems often because they may have fewer resources to operate and maintain compliance. For this reason, EPA, states, and other organizations provide significant resources to small water systems to build their capacity to properly finance, operate, and maintain their drinking water systems. Among other mechanisms to support small systems, EPA funds through the Drinking Water State Revolving Fund and the Public Water System Supervision (PWSS) program for third-party technical assistance providers, and maintains multiple, free online financial and technical websites, tools and resources.