Much progress has been made in achieving the ambitious goals that Congress established 40 years ago to restore and maintain the chemical, physical, and biological integrity of the nation's waters. However, long-standing problems persist, and new problems have emerged. Water quality problems are diverse, ranging from pollution runoff from farms and ranches, city streets, and other diffuse or "nonpoint" sources, to "point" source discharges of metals and organic and inorganic toxic substances from factories and sewage treatment plants. The principal law that deals with polluting activity in the nation's streams, lakes, estuaries, and coastal waters is the Federal Water Pollution Control Act (P.L. 92-500, enacted in 1972), commonly known as the Clean Water Act, or CWA. It consists of two major parts: regulatory provisions that impose progressively more stringent requirements on industries and cities to abate pollution and meet the statutory goal of zero discharge of pollutants; and provisions that authorize federal financial assistance for municipal wastewater treatment plant construction. Both parts are supported by research activities, plus permit and enforcement provisions. Programs at the federal level are administered by the Environmental Protection Agency (EPA); state and local governments have primary day-to-day responsibilities to implement CWA programs through standard-setting, permitting, enforcement, and administering financial assistance programs. The water quality restoration objective declared in the 1972 act was accompanied by statutory goals to eliminate the discharge of pollutants into navigable waters by 1985 and to attain, wherever possible, waters deemed "fishable and swimmable" by 1983. Although those goals have not been fully achieved, considerable progress has been made, especially in controlling conventional pollutants (suspended solids, bacteria, and oxygen-consuming materials) discharged by industries and sewage treatment plants. Progress has been mixed in controlling discharges of toxic pollutants (heavy metals, inorganic and organic chemicals), which are more numerous and can harm human health and the environment even when present in very small amounts—at the parts-per-billion level. Moreover, efforts to control pollution from diffuse sources, termed nonpoint source pollution (rainfall runoff from urban, suburban, and agricultural areas, for example), are more recent, given the earlier emphasis on "point source" pollution (discharges from industrial facilities and municipal wastewater treatment plants). Overall, data reported by EPA and states indicate that 44% of river and stream miles assessed by states and 64% of assessed lake acres do not meet applicable water quality standards and are impaired for one or more desired uses. In 2006 EPA issued an assessment of streams and small rivers and reported that 67% of U.S. stream miles are in poor or fair condition and that nutrients and streambed sediments have the largest adverse impact on the aquatic species in these waters. Approximately 95,000 lakes and 544,000 river miles in the United States are under fish-consumption advisories (including 100% of the Great Lakes and their connecting waters), due to chemical contaminants in lakes, rivers, and coastal waters, and one-third of shellfishing beds are closed or restricted, due to toxic pollutant contamination. Mercury is a contaminant of growing concern—as of 2003, 45 states had issued partial or statewide fish or shellfish consumption advisories because of elevated mercury levels. The last major amendments to the CWA were the Water Quality Act of 1987 ( P.L. 100-4 ). That legislation culminated six years of congressional efforts to extend and revise the act and were the most comprehensive amendments since 1972. Authorizations of appropriations for some programs provided in P.L. 100-4 , such as general grant assistance to states, research, and general EPA support, expired in FY1990 and FY1991. Authorizations for wastewater treatment funding expired in FY1994. None of these programs has lapsed, however, as Congress has continued to appropriate funds to implement them. EPA, states, industry, and other citizens continue to implement the 1987 legislation, including meeting the numerous requirements and deadlines in it. The Clean Water Act has been viewed as one of the most successful environmental laws in terms of achieving its statutory goals, which have been widely supported by the public. Lately, however, some have questioned whether additional actions to achieve further benefits are worth the costs, especially in view of the continuing problems of the U.S. economy. Criticism has come from industry, which has been the long-standing focus of the act's regulatory programs and often opposes imposition of new stringent and costly requirements. Criticism also has come from developers and property rights groups who contend that federal regulations (particularly the act's wetlands permit program) are a costly intrusion on private land-use decisions. States and cities have traditionally supported water quality programs and federal funding to assist them in carrying out the law, but many have opposed CWA measures that they fear might impose new unfunded mandates. Many environmental groups believe that further fine-tuning and strengthening of the law is needed to maintain progress achieved to date and to address remaining water quality problems. October 2012 marked the 40 th anniversary of passage of the Clean Water Act and 25 years since the last major amendments to the law were enacted. While, as noted, there has been measurable clean water progress as a result of the act, observers and analysts agree that significant water pollution problems remain. However, there is less agreement about what solutions are needed and whether new legislation is required. Several key water quality issues exist: what additional actions should be taken to implement existing provisions of the law, whether additional steps are necessary to achieve overall goals of the act that have not yet been attained, how to ensure that progress made to date is not lost through diminished attention to water quality needs, and what is the appropriate federal role in guiding and paying for clean water infrastructure and other activities. For some time, efforts to comprehensively amend the act have stalled as interests have debated whether and exactly how to change the law. Many issues that might be addressed involve making difficult tradeoffs between impacts on different sectors of the economy; taking action when there is technical or scientific uncertainty; and allocating governmental responsibilities among federal, state, local, and tribal entities for implementing the law. These factors partly explain why Congress has recently focused legislative attention on narrow bills to extend or modify selected CWA programs, rather than taking up comprehensive proposals. Other factors also have been at work. These include a general reluctance by some Members of Congress to address controversial environmental issues in view of the relatively slim majorities held by political parties in the House and the Senate; a lack of legislative initiatives by the Administration on clean water issues (neither the Clinton nor the Bush Administration proposed CWA legislation, nor has the Obama Administration); and the high economic cost of addressing water infrastructure issues. Two CWA issues that have been the focus of much of legislators' interest in recent Congresses received some attention again in the 112 th Congress—water infrastructure financing, and regulatory protection of wetlands—but with different focus than in the recent past. After the 2010 election, congressional leadership and priorities shifted—particularly in the House, which used both oversight and legislation to focus criticism on EPA regulatory activities. The 112 th Congress enacted two bills that amend the CWA. One extended the moratorium for CWA permitting of certain vessels for an additional year, until December 18, 2014 ( P.L. 112-213 ), and the other extends authorization of funds for the Lake Pontchartrain Basin program in Section 121 of the act through FY2017 ( P.L. 112-237 ). With the 113 th Congress divided like the 112 th into a Republican-controlled House and a Democratic-controlled Senate, and President Obama having been re-elected, consideration of environmental issues generally, including water quality, reflected those of the previous two years. In addition to enacting appropriations bills (see " Continuing Issue: Appropriations "), the 113 th Congress enacted several bills with CWA provisions. Provisions of water resource legislation creating a pilot program for water infrastructure financing, plus some amendments to CWA Title VI (see " WIFIA Pilot Program and SRF Amendments in P.L. 113-121 "); As part of the 2014 farm bill, legislation exempting silviculture activity from requiring a CWA permit (see " CWA Permits for Logging Road Discharges "); Legislation providing an additional three-year moratorium for CWA permitting of certain vessels (see CRS Report R42142, EPA's Vessel General Permits: Background and Issues ); and A bill eliminating a number of statutorily required reports to Congress, including one CWA report ( P.L. 113-188 ). Meeting the nation's needs to build, upgrade, rebuild, and repair wastewater infrastructure is a significant element in achieving the CWA's water quality objectives. The act's program of financial aid for municipal wastewater treatment plant construction is a key contributor to that effort. Since 1972 Congress has provided nearly $90 billion to assist cities in constructing projects to achieve the act's requirements for secondary treatment of municipal sewage (equivalent to 85% reduction of wastes), or more stringent treatment where required by local water quality conditions. State and local governments have spent more than $25 billion of their own funds for construction, as well. Federal funds can only be used for construction purposes (i.e., new plants or upgrades), but not for operation and maintenance of facilities, which are funded from local sources. Still, funding needs remain very high: an additional $298 billion, according to the most recent Needs Survey estimate by EPA and the states, released in June 2010, a 17% increase above the estimate reported four years earlier.