The principal federal program to aid municipal wastewater treatment plant construction is authorized in the Clean Water Act (CWA). Established as a grant program in 1972, it now capitalizes state loan programs. Authorizations since 1972 have totaled $65 billion, while appropriations have totaled nearly $90 billion. It has represented 25%-30% of total funds appropriated to the Environmental Protection Agency (EPA) in recent years. In appropriations legislation, funding for EPA wastewater assistance is contained in the measure providing funds for the Department of the Interior, Environment, and Related Agencies, which includes EPA. Within the portion of that bill which funds EPA, wastewater treatment assistance is specified in an account now called State and Tribal Assistance Grants (STAG). Three trends in the funding of this account are most prominent: inclusion of non-infrastructure environmental grants to states, beginning in FY1993; increasing number and amount of special purpose grants since FY1989; and the addition of grant assistance for drinking water treatment projects in FY1997. This report summarizes, in chronological order, congressional activity to fund items in this account since 1987. Prior to the 1987 amendments, wastewater treatment assistance was provided in the form of grants made to municipalities. The federal share of project costs was generally 55%; state and local governments were responsible for the remaining 45%. The 1987 amendments altered this arrangement by replacing the traditional grant program with one that provides federal grants to capitalize state clean water loan programs, or state revolving funds (SRFs). Appropriations for the clean water SRF program through FY2015 have totaled more than $40 billion. As a general matter, states and cities support the program changes made by the 1987 amendments and the shift to a loan program that was intended to provide long-term funding for water quality and wastewater construction activities. However, the change means that local communities now are responsible for 100% of project costs, rather than 45%, because they are required to repay loans to states. The greater financial burden of the act's loan program on some cities has caused some to seek continued grant funding. This has been particularly evident in the appropriations process where, in recent years, Congress has reserved as much as 30% of funds in the STAG account for special purpose grants directed to specified communities. Since FY2000, appropriators have awarded earmarks to a larger total number of projects, resulting in more communities receiving such grants, but at the same time receiving smaller amounts of funds, on average. Most of the funded projects are not authorized in the Clean Water Act or the Safe Drinking Water Act. State water quality officials, state infrastructure financing officials, and EPA have objected to this practice, since it reduces the amount of funding for state SRF programs. Since FY1997, the STAG account also has been used to fund a drinking water SRF program established by Congress in 1996. Appropriations for the drinking water SRF program through FY2015 have totaled $19.1 billion.