In 2003, the U.S. Environmental Protection Agency (EPA) conducted the third Drinking Water Infrastructure Needs Survey and Assessment (DWINSA or Assessment). The Assessment is an important tool of the Drinking Water State Revolving Fund (DWSRF) program. The purpose of the Assessment is to estimate the documented 20-year capital investment needs of public water systems that are eligible to receive DWSRF assistanceapproximately 53,000 community water systems and 21,400 not-for-profit noncommunity water systems. The Assessment includes infrastructure needs that are required to protect public health, such as projects to comply with National Primary Drinking Water Regulations or to prevent contamination by preserving the physical integrity of the system.1 The Safe Drinking Water Act (SDWA) requires EPA to conduct the Assessment every four years and to use the results to allocate DWSRF funds to the States and Tribes. The approach for the 2003 Assessment was developed by EPA in consultation with a workgroup of State representatives. The workgroup refined the methods used in 1995 and 1999 based on lessons learned from the previous Assessments and options made available from technological advancements in internet-based communications. The 2003 Assessment used questionnaires to collect infrastructure needs from medium and large water systems. EPA mailed questionnaires to all 1,342 of the nations largest water systems serving more than 40,000 people, and to a random sample of 2,553 of the 7,759 medium systems serving over 3,300 people. Approximately 96 percent of these systems returned the questionnaire. Small systems serving fewer than 3,300 people often lack the specialized staff and planning documents needed to respond to the questionnaire. Therefore, for the 1999 Assessment EPA conducted site visits to 599 randomly selected small community water systems and 100 not-for profit noncommunity water systems to identify and document their infrastructure needs. EPA did not conduct the site visits as part of the 2003 Assessment; instead, it used the 1999 Assessment, updated for inflation to January 2003 dollars.