Clean Water Act – An Overview


In 1948, Congress adopted the Federal Water Pollution Control Act, 33 U.S.C. §§ 1251-1387.  In 1972, that law was significantly amended.  The 1972 law and its subsequent amendments are commonly known as the Clean Water Act (“CWA”). The objective of the CWA is “to restore and maintain the chemical, physical, and biological integrity of the Nation’s waters.”  The CWA operates by authorizing water quality standards for surface waters, requiring National Pollution Discharge Elimination System (NPDES) permits for “point source” discharges of pollutants into navigable waters, assisting with funding for construction of municipal sewage treatment plants, and planning for control of nonpoint source pollution.

The CWA is the primary legal and policy instrument for regulating the pollution of the nation’s waters.  The Environmental Protection Agency (“EPA”) is the primary agency tasked with implementing and enforcing the CWA, although it also works in conjunction with state environmental agencies and the U.S. Army Corps of Engineers.

The CWA applies to non-agriculture individuals and entities throughout the United States, including the agricultural sector.  The CWA is a major pillar of the environmental law affecting agriculture. Reading Rooms that address other aspects of the environmental laws affecting agriculture include the Animal Feeding Operations, Conservation Programs, Pesticides, Environmental Law, and the National Organic Program reading rooms.

Scope and Operation

The CWA regulates navigable waters, defined in the statute as the “waters of the United States,” a term that is further defined by agency regulations and judicial interpretations.  The EPA begins by assigning water quality standards to all parts of a watershed that are within the scope of the CWA. State agencies may also apply standards to waterbodies not directly covered by the CWA. Water quality standards are scientifically measurable standards that quantify the goals of the CWA and include designated uses, water quality criteria, and antidegradation policies. Designated uses are the uses of a waterbody that society would like to achieve in a location such as fishing, industrial water supply, or agricultural irrigation.

Multiple designated uses can be assigned for a particular waterbody or portion of a waterbody. The water quality criteria are the technical conditions required to reach the designated uses in a particular water body including concentrations of pollutants, temperature, pH, and “no toxic chemicals in toxic amounts.” However, acceptable water quality criteria can also include narrative descriptions that are difficult to scientifically quantify such as no objectionable bottom deposits, no unsightly floating debris, or no nuisance odor or color. Antidegradation policies are rules used by states to govern future uses of a watershed that may adversely impact high water quality areas that currently exceed the standards required for their designated uses. These policies are designed to protect areas of water that are already higher than standards require and prevent their degradation or loss of existing uses.

Designated Uses

When assigning designated uses to waterbodies, several policies must be followed. Any use that the waterbody achieved since November 28, 1975, even if it is not possible at present, must be included in the designated uses for that waterbody. Because the broad goals of the CWA include fishing and swimming, every waterbody must include those designated uses unless the downgrading process has been followed to allow the reduction of quality in a waterbody. Waste transport may never be a designated use. If multiple designated uses are defined for a waterbody, the designated uses requiring the highest water quality sets the standard.

Designated uses may only be reduced by following a downgrade process that demonstrates that the water quality goals are unattainable because of natural background conditions, irreversible human-caused conditions, resulting substantial environmental harm, or excessive social and economic cost. Under EPA regulations, an existing use may never be removed from the designated uses for a waterbody.

Water Quality Standards

Although the states have the authority to establish water quality standards for their waters, the EPA must approve them, and if the EPA feels that it will not reach an agreement with a state, it may promulgate water quality standards through the federal rulemaking process. This process allows for public comment on the proposed water quality standards.

After standards for water quality are established, states must then monitor their waterbodies to determine if the water quality standards are being met. Continuous monitoring of all water is not feasible so monitoring is usually implemented through random sampling used to generate statistical reports about the water quality of a waterbody.  The CWA requires that states send reports to the EPA detailing known information about bodies of water and a list of waters that do not meet their water quality standards.

The EPA allows exemptions from water quality standards in mixing zones and during times of design flow. These exemptions primarily accompany point source discharges. The mixing zone is typically downstream from point source discharges, and design flow occurs during extreme high flow and extreme low flow events around the location of the point source discharge.

Total Maximum Daily Load

If a waterbody does not attain the proper water quality standards, then a strategy is implemented to reach the required standard. The most common approach is the use of a Total Maximum Daily Load (“TMDL”), which is the maximum amount of a pollutant in a particular area of an impaired waterbody that would allow the water quality standards to be met. Ideally, TMDLs are adopted on a watershed basis so that a comprehensive system of restoration and antidegradation of water quality is reached. TMDLs must be approved by the EPA, and if the EPA and the state cannot agree, the EPA may establish a TMDL through federal rulemaking.

Pollution Reduction

Once the TMDL is established for a waterbody, then the allowable amount of pollutant discharge is divided among various sources as determined by the states. These allocations are called Wasteload Allocation for point sources and Load Allocation for nonpoint sources. The Wasteload Allocation for a point source is generally included as part of its permit for pollution discharge.

Once desired pollutant levels are identified by TMDLs, state and federal programs are used to achieve reductions in the pollutant. The CWA includes several mechanisms to reduce pollutants: National Pollutant Discharge Elimination System (“NPDES”) permits, § 404 dredge and fill permits, grants for nonpoint source pollution reduction and CWA programs, a § 401 certification program, and a revolving loan fund for construction or improvement of water treatment plants.

National Pollutant Discharge Elimination System

The NPDES system requires a permit before any pollutant can be discharged from a point source into a navigable water. The term pollutant has been broadly defined and includes heat, waste, soil, rock, chemical materials, and biological materials. The permits set the allowable amount of pollutants in a discharge, and the Wasteload Allocation derived from the allocation of the TMDL is included as part of the permit. Point sources cover many manmade objects including pipes, ditches, tunnels, airplanes, but do not cover return flows from irrigated agriculture, small feedlots, or sewage from certain ships. Certain confined animal feeding operations and the runoff from their operations are one important type of point source that is regulated by the CWA.

NPDES permits are issued by the EPA or by states if they have a program that satisfies the EPA. Permits may be issued to individual dischargers or to groups of similar dischargers. Dischargers that send waste into a sewage treatment plant do not need a NPDES permit, but they must meet pretreatment criteria under the CWA.

The permits set measurable limits on the amounts of pollutants allowed to be discharged. The limits may be based either on technology (“technology limits”) or water quality standards, and they are written so that they cannot be attained simply by dilution of the wastewater. Permits may also contain best management practices (“BMP”) requirements. These are the best known and most practical methods for reducing pollution levels in a particular industry.

Nonpoint source pollution (“NPS”) is the largest contributor to the pollution of waters of the United States. NPS is defined as anything that is not a point source and consists of runoff from overland areas, including agricultural areas, and air pollution returned to earth through precipitation. The CWA does not regulate NPS, but it does provide for grants to states to develop programs to manage NPS. The management plans must identify waters impaired or threatened by NPS, define goals for cleaning those waters, and list the BMP that will be used to achieve the goals.

Dredged and Fill Material Permits

The § 404 program regulates the deposit of dredged and fill material into waters of the United States. This part of the CWA has broad implications for agriculture, particularly in the area of wetlands. It serves as a wetland protection law even though wetlands are not specifically mentioned in the statute.

The U.S. Army Corps of Engineers issues § 404 permits. However, the EPA does have the authority to veto a Corps permit. The U.S. Fish and Wildlife Service also comments on applications regarding the proposed activities’ impacts on wildlife. After issuance of the permit, the Corps is responsible for compliance with permits and determinations of whether an area is part of the waters of the United States.

Federal Permit and License Certification

The § 401 program requires that any federal agency that issues permits or licenses that may result in any discharge into the waters of the United States obtain from the state a certificate that the discharge is acceptable under the CWA. It also contains procedures for downstream states whose water quality may be affected to participate in the process.

State Revolving Loan Fund

The State Revolving Loan Fund is a CWA program that allows the EPA to provide grants to states to establish loan funds. These state funds then provide low interest loans to municipalities, businesses, or nonprofit organizations for water quality projects. Most of the loans have been used for the construction, repair, or expansion of municipal sewage treatment plants, but money can also be used for NPS projects.