CPR Perspective: TMDLs, Nonpoint Source Pollution, and the Goals of the Clean Water Act

More than three decades after enactment of the Nation's major water pollution-fighting statute, the Clean Water Act (CWA), significant water pollution problems remain throughout the United States. Many waters are unsafe for fishing, swimming, boating, and other human uses, and a large number of aquatic ecosystems are ecologically unhealthy.

The overarching goal of the CWA is to "restore and maintain the chemical, physical, and biological integrity of the Nation's waters." The key indicators of whether this broad goal is met are water quality standards (WQS) adopted by individual states and approved by EPA. (EPA issues WQS where states fail to do so adequately.) WQS are divided into two components. "Beneficial uses" constitute the purposes for which a water body is to be protected; while water quality criteria (WQC) establish conditions necessary to protect those beneficial uses. Such standards establish the goals for individual water bodies and provide one legal basis for pollution control decisions under the Act. WQS must "protect the public health or welfare, enhance the quality of water and serve the purposes of this chapter."

Unfortunately, based on state monitoring and assessment, WQS continue to be violated in a large percentage of our rivers, lakes and coastal waters, although many waters are not even tested for violations. We can attribute some WQS violations to inadequate pollution controls on particular "point sources," discharges from factory pipes, public sewage facilities, and other discrete pollution sources. The biggest reason for this ongoing impairment, however, is our failure to address aggregate harm from more diffuse but ubiquitous sources of pollution, so-called "nonpoint sources." Those sources include runoff pollution from land uses such as farming, grazing, logging, and development, and other kinds of impairment of natural aquatic ecosystems, such as dams, water diversions, dredging, and river channelization.

One existing provision in the Clean Water Act stands out as having sufficient promise to meet this challenge. Section 303(d) of the Act calls on the states or EPA to calculate "total maximum daily loads" (TMDLs) from all sources contributing to the pollution of a single water body, and to allocate among those sources the pollution reductions necessary to correct the problem. Until recently, this provision of the law was used only sporadically. It has been rejuvenated, however, both due to EPA's emphasis on watershed approaches to water pollution control, and to a rash of citizen suit litigation initiated during the 1990s. States are now writing TMDLs for thousands of water bodies around the country.

Section 303(d)(1) requires each state to identify those waters for which the Act's technology-based standards were not strict enough to achieve any WQS. Next, states must identify a "total maximum daily load" (TMDL) for each pollutant at a level necessary to implement the standard. In essence, a TMDL is the combined amount of pollution the state believes a water body can accept without exceeding the WQS, and an allocation of pollution reductions needed from existing sources to meet that target. States then submit the lists of waters and accompanying TMDLs to EPA, which approves the submission or promulgates its own list and TMDLs.

The TMDL process itself, however, does not necessarily ensure that the pollution reduction targets will be achieved. For point sources, states are supposed to translate TMDLs into stricter permit limits. The Act does not, however, include similar mandatory controls for nonpoint sources. Instead, Congress left it to individual states to decide how best to control pollution from those sources, and most states continue to do so entirely through voluntary programs such as education and financial assistance. Failure to control nonpoint sources adequately remains the biggest single challenge in water pollution control. A recent U.S. Court of Appeals decision, however, confirms that TMDLs are required even for water bodies impaired entirely by nonpoint sources, as well as for waters impaired by both point and nonpoint sources.

In the late 1990s, EPA established an advisory committee under the Federal Advisory Committee Act (FACA), comprised of representatives of diverse stakeholders, to generate recommendations on how to clarify and improve the TMDL program with respect to these and other issues. Based on largely consensus recommendations of the FACA committee, in July of 2000 EPA promulgated revised regulations governing the TMDL program. Under these regulations, states would have been required to adopt and publicize more detailed methods for identifying and listing impaired waters. EPA required states to identify all impaired waters on these lists, but to require TMDLs only for water in which harm occurred due to discharges of chemical pollutants, as opposed to the many other sources of water body impairment. States were required to issue TMDLs for all of those waters within fifteen years. Perhaps most significantly, the new regulations required states to adopt implementation plans indicating how all of the required pollution controls needed to comply with the TMDLs would occur. This new provision closed the longstanding gap between the regulatory goals of the CWA and action. While the regulations did not require states to adopt mandatory controls on nonpoint sources, it at least required them to provide "reasonable assurances" (in ways specified in the rule) that pollution from nonpoint sources would be curtailed, so that WQS would be met.

Unfortunately, EPA's July 2000 regulation never took effect due to opposition from a coalition of agricultural and industry groups. First, in response to industry lobbying, Congress passed an appropriations rider prohibiting EPA from spending any money to implement the new regulations. Next, various groups filed lawsuits challenging EPA's regulation in court. Eventually, in March 2003, EPA withdrew the regulations entirely. While EPA has tried to meet some of the objectives of the regulation through unenforceable regulatory guidance, the implementation plans and other key aspects of the July 2000 rule have been abandoned.

For decades, point sources have been subject to mandatory controls designed to protect human health and the environment from the serious water pollution that plagued the country before Congress adopted the modern CWA in 1972. While this system of controls is far from perfect, and while enforcement of permit obligations is often weak, significant progress has still been achieved in addressing those sources of pollution. At the same time, nonpoint sources have consistently avoided any mandatory or other significant pollution control obligations.

One irony of the TMDL program is that, absent requirements that translate "paper" TMDLs into actual pollution reductions, the process could actually weaken controls on both point sources and nonpoint sources. In theory, operators of point sources should favor strict TMDL requirements - including accompanying controls on nonpoint sources - because that system would spread pollution control requirements fairly among various sources. In this zero sum game, if nonpoint source pollution is curtailed, more expensive controls on point sources could be avoided. Economists should favor this approach because the marginal costs of increasingly strict point source controls are likely to be far higher than the most basic kinds of nonpoint source controls, many of which have not been implemented at all. However, a system in which states must write TMDLs but have no mandatory implementation obligations can result in reduced controls on both point and nonpoint sources, at the expense of health and environmental quality. If more pollution reductions are "assigned" on paper to nonpoint sources, less control will be required of point sources. But if the nonpoint source controls are not actually required, the TMDL process becomes a sham exercise and WQS will continue to be violated.

What was supposed to be a "zero sum" game has become nothing more than a game, in which the states and EPA devote significant time and resources to listing impaired water bodies and writing paper TMDLs, with no accompanying assurance that additional pollution controls will occur. EPA could correct this problem by re-promulgating its July 2000 regulations, including the pivotal implementation plan requirement. Alternatively, Congress could recognize that the entirely voluntary system for addressing nonpoint source pollution is not working, and amend the CWA to require that all sources of water pollution do their fair share to ensure that America's waters are safe for drinking, fishing, swimming, and aquatic ecosystems.

For more information, read 

• Robert W. Adler, "Integrated Approaches to Water Pollution: Lessons from the Clean Air Act," 23 Harv. Envtl. L. Rev. 203 (1999)
• Robert W. Adler, "The Two Lost Books in the Water Quality Trilogy: The Elusive Objectives of Physical and Biological Integrity," 33 Envtl. L. 29 (2003).