"Introduction Since the first edition of Guide to Groundwater Standards of the United States was published in 1983@ regulations at both the state and federal levels have been greatly expanded. A partial listing of groundwater related events of the last two years includes; ? Establishment of EPA's Office of Groundwater in April 1984 to coordinate groundwater programs administered by the agency's other offices ? Establishment of Offices of Groundwater in each of the 10 EPA regions ? Issuance of a final Underground Injection Control (UIC) program by EPA in May 1984@ with final UIC regulations promulgated in November 1984 ? Release of the final EPA Groundwater Protection Strategy on 30 August 1984 ? Major amendments to RCRA@ with provisions for regulating underground storage tanks ? Expansion of activities under CERCLA during 1984 ? Final regulations on groundwater testing and monitoring under RCRA ? Establishment of the Groundwater Research Review Committee within the Science Advisory Board in the fall of 1984 ? Approval of many state UIC programs ? Approval of many state RCRA programs ? Additional designations of sole source aquifers@ with others ? Proposed Proposed revisions to groundwater quality criteria and standards by many states ? Aquifer contamination studies by the US Geological Survey (USGS) in most states ? A National Groundwater Policy Forum@ comprising state@ industry@ and environmental groups@ announced in January 1985 ? Promulgation in January 1985 of a new 40 CFR 130 on ""(State) Water Quality Management and Planning@"" which recommends elements of state groundwater management plans ? Development of Groundwater Protection Programs by many states ? Development of a Memorandum of Understanding on groundwater programs among EPA@ USGS@ and the Bureau of Reclamation Because of these events and others@ the American Petroleum Institute (API) recognized the need to update its Guide to Groundwater Standards of the United States. They retained Lawler@ Matusky Skelly Engineers to compile pertinent information on federal and state regulations@ standards@ and programs concerning the use and protection of groundwater@ and to revise where necessary the 1983 version of the guide. This Guide to Groundwater Programs of the United States Is composed of two parts. The first part@ Chapters 1-4@ provides an overview of technical and regulatory concepts and terminology and a summary of the federal programs that provide the basis for state regulations. The second part. Chapters 5 and 6@ provides information on state groundwater programs and standards. Chapter 5 is an overview@ and Chapter 6 contains alphabetically arranged summaries for each of the 57 states and territories. Much of the information discussed in this guide@ particularly that related to the 1984 amendments to the Resource Conservation and Recovery Act (RCRA)@ will be superseded as EPA develops regulations to carry out the amendments. Of particular importance will be the new regulations on underground storage tanks@ limitations on land disposal of hazardous wastes@ and further restrictions on small quantity generators (SQGs) of hazardous wastes. It is clear@ therefore@ that the groundwater regulations will be in a state of flux over the next several years. The information provided in this guide is based on regulations effective in September 1985. In using the guide@ the reader should be cognizant of the most recent changes in these programs. To assist the reader@ names of contacts for various state groundwater programs are provided in Chapter 6@ and the regional groundwater coordinators are listed in Chapter 3. These agency staff should be consulted to confirm the current status of standards and regulations concerning groundwater."