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Water: Total Maximum Daily Loads (303d)

Chapter 4 - EPA And State Responsibilities

Guidance for Water Quality-Based Decisions:
The TMDL Process

Effective implementation of water quality-based controls requires an integrated and cooperative partnership between EPA and the States. The main responsibility for water quality management resides with the States in the implementation of water quality standards, the administration of the NPDES program (where the State has received EPA approval to do so), and the management of nonpoint sources of pollution. When the authority to implement nonpoint source control measures is at the local level, interagency and intergovernmental coordination is especially important. The State should take the lead in facilitating and encouraging the cooperation of local authorities. EPA is responsible for ensuring that the Clean Water Act requirements are met through the enactment and enforcement of regulations, issuing program guidance, and providing technical assistance. The partnership developed between States and EPA should be tailored to meet individual State needs while also meeting the requirements of the Clean Water Act. This chapter describes specific State and EPA responsibilities in the partnership.

EPA/State Agreements

EPA and the State should agree on the process to develop TMDLs and this process should be consistent with EPA technical guidance documents unless deviation from the guidance is technically justified. An agreement should be written which describes technical and administrative procedures (i.e., how backgrounddata are applied, how and which models are to be used, how TMDLs are developed, how loads should be allocated, etc.). (See Appendix F for a general EPA/State Agreement outline.) This agreement reduces the administrative burden of the EPA review and approval process (see Figure 3).

State Responsibilities

Identification of Water Quality-Limited Waters Still Requiring TMDLs

According to section 303(d) of the Clean Water Act and EPA water quality planning and management regulations, States are required to identify waters that do not meet or are not expected to meet water quality standards even after technology-based or other required controls are in place. The waterbodies are considered water quality-limited and require TMDLs.

When a State reports its list of 303(d) waters, it is important that this list contain only those water quality-limited waters that still require TMDLs. Some water quality-limited waters may already have had sufficient controls established for them and currently meet water quality standards. These should not be on the list. In addition, the EPA regulations (40 CFR 130.7(b)) recognize the applicability of other appropriate pollution control requirements that can provide a more stringent level of control than technology-based effluent limitations.

When not listing a water quality-limited water a State must show that the controls specified by 40 CFR 130.7(b) (see Chapter 2) are enforceable, specific to the pollution problems, and stringent enough to meet water quality standards. If the controls are not yet implemented, a State must provide a schedule for timely implementation.

The waters identified should be reported to EPA in the 305(b) water quality assessment reports due April 1 every even year. If a State prefers, the 303(d) list of waters can be submitted separately at the same time. While initially it may be convenient to build upon the reporting processes described in Chapter 2, the 303(d) list should be updated to reflect the latest monitoring and assessment data available.

To facilitate the reporting of 303(d) waters, the current section 305(b) Waterbody System (WBS), a tool used for reporting 305(b) information, contains fields already designated for this identification. The WBS provides a geographically based framework for entering, documenting, and reporting information on the quality of individual waterbodies as they are defined by each State. The primary function of the WBS is to document water quality assessments and the water quality status of waterbodies, including causes and sources of use impairment. As a convenience to the States, the WBS has been modified and will continue to be updated to include data fields on whether TMDLs are still needed or are in place. The WBS will also provide information to EPA to assist in tracing the development of TMDLs and overall program implementation.

Identification of Causes and Sources of Pollution - When identifying the 303(d) waters, the causes of the impairment also should be identified for each segment listed. The Waterbody System has two separate fields that provide further information on a particular water segment: "nonattainment causes" and "nonattainment sources." The "cause" field consists of a list of constituents or conditions that are causing nonattainment of water quality standards by a waterbody. The Waterbody System's Users Guide (third edition, version 2.0) contains 23 standard causes (see Appendix G) and includes such parameters or categories as pesticides, metals, ammonia, and pathogens. States may develop their own user-defined codes by specifying additional codes under each standard cause.

Similarly, a field exists in the Waterbody System for identifying the sources of the pollutants or conditions that are listed under causes for the nonattainment of uses in the waterbody. Twelve general source categories are identified (see Appendix G) and include such things as industrial point sources, municipal point sources, combined sewer overflow, agriculture, and silviculture. The User's Guide also identifies 45 subcategories. Again the States may develop their own subcategories to describe causes of impairment of each water segment identified with this system. States should consult with the Guidelines for the Preparation of the 305(b) Report (to be issued every odd numbered year) and the Waterbody System User's Guide for guidance in developing and formatting their information.

Documentation and Rationale for Listing - Along with the list of 303(d) waters submitted to EPA, adequate documentation to support the listing of waters should be submitted. States have a number of readily available sources of data and information to use when compiling their lists (see pages 12 and 13). These sources, listed in Appendix C, should be used by States to develop their lists of 303(d) waters. However, additional information may be required under certain circumstances.

Documentation for listing should also provide a description of the methodologies used to develop the list, a description of the data and information used to identify water quality-limited waters, and a rationale for any decision to not use any one of the categories listed in Appendix C. It is not expected that each and every waterbody listed by a State be accompanied by the detailed documentation as described.

Adequate public participation should be a part of the listing process to make sure all water quality-limited waters are identified. This will support the State in defending its list of such waters should the need to do so arise, since, in its oversight responsibilities, EPA reserves the right to ask for additional information regarding the State's decision to not list particular waterbodies.

Identification and Scheduling of Targeted Waterbodies

Targeted waterbodies scheduled for TMDL development over the next two years are to be identified and reported along with the 303(d) list of waters that are submitted during the 305(b) reporting process. These high priority TMDLs are to be based on State developed priorities that consider the severity of the impact and the uses of the water along with the other considerations described in Chapter 2. State submissions which include the identification of 303(d) targeted waters are subject to review and approval or disapproval by EPA. EPA will expect the States to include public participation in the development of the list of high priority targeted waterbodies. Targeting waterbodies for control action should be a key component of a State's water quality management and planning programs. Waters that are identified in State annual work plans will be compared to the targeted waterbodies and will be considered by EPA during its review and approval of the annual work plans.

TMDL Development

Each State develops TMDLs for its water quality-limited waters. The procedure for TMDL approval by EPA is depicted in Figure 3. States should use EPA's technical support document and WLA technical guidance series (see Appendix A) when developing TMDLs. Alternative approaches can be used if they are technically defensible and approved by EPA.

Figure 3

TMDL Development and Approval Procedure


For their TMDL submissions, States should include the proposed TMDLs, WLAs, LAs, and the supporting information that the Region will need to evaluate the State's water quality analysis and determine whether to approve or disapprove the submitted TMDLs. Regions and States should reach an agreement on the specific information needed prior to their submission. For a TMDL developed under the phased approach, States should also submit to EPA a description of the controls to be established, the schedule for data collection, establishment of the control measures, assessment for water quality standards attainment, and additional modeling if needed.

Quality assurance (QA) and quality control (QC) requirements should also be met. Specific technical QA/QC is necessary in the use of environmental data and models. However, when using models, such as wasteload allocation models which involve "real" environmental data as well as parametric and mathematical relationships, model sensitivity studies can help establish the levels of QA/QC required for specific data. For example, the allowable range of uncertainty in the data can be established through model sensitivity studies. This allowable range of uncertainty may indicate, for example, the need for tight limits on precision for a particular pollutant parameter. Further discussion is provided elsewhere. 13 14 15

Continuing Planning Process

Each State is required to establish and maintain a continuing planning process (CPP) as described in section 303(e) of the Clean Water Act. A State's CPP contains, among other items, a description of the process that the State uses to identify waters needing water quality-based controls, a priority ranking of these waters, the process for developing TMDLs, and a description of the process used to receive public review of each TMDL. Descriptions may be as detailed as the Regional office and the State determine is necessary to describe each step of the TMDL development process. This process may be included as part of the EPA/State Agreement for TMDL development.

Water Quality Management Plan

The State incorporates EPA approved and EPA established TMDLs into its Water Quality Management Plan (WQMP). The Water Quality Management and Planning regulation provides that when EPA approves or establishes a TMDL under section 303(d), the TMDL is automatically incorporated into the State's WQMP. 16

Public Notice and Participation

In accordance with the Water Quality Management and Planning regulation and as described in a State's CPP, the TMDLs should be made available for public comment. States and involved local communities should participate in determining which pollution sources should bear the treatment or control burden needed to reach allowable loadings. By involving the local communities in decision making, EPA expects that a higher probability of successful TMDL implementation will result.

In the identification of water quality-limited waterbodies, States need to involve the public as part of their review of all existing and readily available data and information. This is especially true in such cases where a waterbody may be perceived as being at risk due to new dischargers and changes in land use. In such cases a waterbody's water quality may be "threatened" and therefore should be given consideration for listing as a 303(d) water. EPA expects States to include public participation in its development of high priority targeted waterbodies that will proceed with TMDL development within two years following the listing process.

In the development of a TMDL, a State should issue a public notice offering an opportunity for a public hearing pertinent to the TMDL under review. It is recommended that this be done in conjunction with public notices and hearings on NPDES permits, construction of municipal wastewater treatment works, water quality standards revisions, and Water Quality Management Plan updates. Each notice should identify TMDLs as part of the subject matter.The State may wish to proceed to issuance of a final TMDL without a hearing once notice is given and there has been little or no response by the public.

Also, if a State determines that the water quality-based controls may be controversial, the State should involve the EPA Regional office, as well as the public, early in the process and continue to involve them throughout the process.


State submission of a list of waters still needing TMDLs and loads established is required by the Clean Water Act and the Water Quality Planning and Management regulations (40 CFR 130.7). These lists should complement EPA/State Agreements and the CPP, and be incorporated into the WQMP. States should submit the 303(d) lists either as part of or at the same time as the biennial section 305(b) reports. As part of this reporting requirement, States are expected to identify those waters targeted for TMDL development in the next two years. Targeted waterbodies are then scheduled for TMDL development through the annual work plan. In addition, the pollutants or conditions causing violations of water quality standards and the point and nonpoint sources of the pollution causing those conditions should be identified for each waterbody on the 303(d) list (see page 28). States should consult the Section 305(b) Waterbody System's Users Guide (August, 1989) to appropriately categorize sources and causes of pollutants.

Other Specific Responsibilities

Other State responsibilities are to

  • Ensure that needed environmental data are provided to EPA, including appropriate assessment data; appropriate screening data; and all regulatory data including data needed for approvals of the 303(d) lists and TMDLs, and
  • Ensure that appropriate quality assurance/quality control procedures are used for all data used in State decision making and for all data reported to EPA, including data reported by dischargers.

EPA Responsibilities

Review of 303(d) Lists

Section 303(d) and the Water Quality Planning and Management Regulation (40 CFR 130.7(d)) requires EPA to review and approve or disapprove States' lists of water quality-limited waters and the established pollutant loads. The lists are expected to be submitted biennially and will be approved or disapproved based in part on the State's documentation and rationale for developing such lists as described under the State Responsibilities section of this chapter.

If, after reviewing the State lists and documentation, EPA is satisfied that the State has identified and appropriately listed all impaired waters and those targeted for action, EPA will then approve the lists and send a letter approving the submittal to the State. During this approval process, EPA may request a State to provide additional information if there is "good cause" to do so. "Good cause" may include, but is not limited to, more recent or accurate data; more accurate water quality modeling; flaws in the original analysis that led to the water being identified pursuant to 40 CFR 130.7; or changes in conditions (e.g., elimination of discharges).

If the EPA disapproves (via a letter of disapproval to the State) a State's list of waters needing new or revised TMDLs and those targeted for action, the Region (working closely with the State) then identifies those waters where new or revised, and targeted TMDLs are necessary.

TMDL Review and Approval

Section 303(d) and the Water Quality Planning and Management regulation (40 CFR 130.7(d)) requires EPA to review all TMDLs for approval or disapproval. EPA may tailor its review to what is reasonable and appropriate. For example, where a State has clearly described its TMDL process in its approved CPP (and EPA/State Agreement), EPA may conduct an in-depth review of a sample of the State's TMDLs to determine how well the State is implementing its approved process and conduct a less detailed review of the remaining TMDLs. This in-depth review of samples of the State submissions, in conjunction with a less detailed review of all other TMDLs submitted to EPA by the State, will provide a reasonable basis for EPA approval or disapproval of individual TMDLs. The in-depth sample review may include TMDLs supporting major construction projects and other major control measures. For those States that do not have an approved process, Regions are expected to conduct in-depth reviews of all TMDLs. The Region's review should also consider how well the States are following applicable technical guidance for establishing TMDLs, WLAs, and LAs.

EPA must, at a minimum, determine whether the State's TMDLs are "established at a level necessary to implement the applicable water quality standards with seasonal variations and a margin of safety that takes into account any lack of knowledge concerning the relationship between effluent limitations and water quality." 17 No TMDL will be approved if it will result in a violation of water quality standards.

If the State chooses not to develop the needed TMDLs for appropriate pollutants on a timely basis or, if the TMDLs are unacceptable to EPA, EPA has a role under the Act to develop the TMDLs in cooperation with the State. 18 This will be done by focusing available EPA resources on the most critical water quality problems.

EPA must either approve or disapprove the State's TMDL within 30 days after submission by the State. Where a TMDL is approved, EPA transmits a letter of such approval. If EPA disapproves a State's submission and the State does not agree to correct the problems, then EPA shall, within 30 days of the disapproval date, establish such TMDLs as necessary to implement the water quality standards. EPA solicits public comment and after considering public comment and making appropriate revisions, EPA transmits the revised TMDL to the State for incorporation in the State's Water Quality Management Plan.19 EPA prefers to discharge this duty through a cooperative effort with the States.

Program Audits

EPA expects to measure performance on the basis of environmental results and administrative goals by means of program audits. To achieve this performance measurement, EPA will periodically conduct audits of State water quality programs primarily through Regional visits to the States, review of State toxics control programs, and State action plan summaries of EPA's Surface Water Toxics Control Program.20 These program audits will serve to determine where additional training or other assistance may be needed and to determine implementation of program objectives.

Technical Assistance and Training

EPA Headquarters and Regional offices are available to provide technical assistance and advice to the States in developing TMDLs. EPA Headquarters in coordination with the EPA Center for Exposure Assessment Modeling (CEAM) provides for training and assistance on modeling. EPA Headquarters also provides training and technical assistance to users of the Waterbody System (WBS).

Guidance Documents and Reports

EPA Headquarters is responsible for developing associated program guidance, technical support with assistance from EPA research laboratories, and producing the biennial National Water Quality Inventory Report to Congress developed from the State section 305(b) assessment reports.

EPA Headquarters Responsibilities

EPA Headquarters is responsible for making sure the CWA mandates regarding TMDLs are carried out, providing oversight of the Regional offices and the States, developing program policy and guidance, supporting the development of computer software for calculating TMDLs, developing technical guidance documents, and providing technical training and assistance. Other responsibilities of EPA Headquarters are summarized on the next page.

EPA Regional Responsibilities

The EPA Regional offices are responsible for assisting Headquarters in developing policy and guidance, distributing policy and guidance to the States, awarding grants to the States for developing and implementing water quality-based controls, and providing technical assistance to the States. In addition, the Regional offices are responsible for reviewing and approving or disapproving the following: each State's TMDL process, the annual work program, the list of waters where TMDLs are needed, the list of targeted waters, and specific TMDLs, WLAs, and LAs. The EPA Regional offices are also responsible for reporting on State implementation to Headquarters. Other responsibilities of EPA Regional offices are summarized below.

Other EPA Headquarters Responsibilities
  • Prepare guidance and ensure that appropriate technical training and technical assistance is available for monitoring, water quality analysis, and data reporting.
  • Perform national assessments and evaluate the national water quality effects of CWA programs.
  • Make national data systems more useful for national, regional, and State manages by upgrading and cross-linking the existing systems and developing interactive data retrieval and analysis mechanisms for line managers. Continue support of the River Reach and Industrial Facility Discharge Files.
  • Ensure the appropriate quality assurance/quality control procedures are used in all national data collection efforts and provide laboratory support for national studies of pollutants requiring special analyses.
  • Prepare headquarters budget requests, and in consultation with the Regions, prepare requests for Regional and State water quality monitoring and analysis programs.
  • Peer review major agency program activities involving water monitoring and consult with other program offices on water monitoring activities.
Other EPA Regional Responsibilities
  • Ensure that the appropriate regulatory monitoring is performed by the States and dischargers needed for developing and implementing water quality-based controls and identifying needed nonpoint source controls. This includes data required to identify water needing water quality-based controls, data needed to develop controls, and data needed to assess the effectiveness of controls.
  • Provide technical assistance and training to the Sates on water quality monitoring and analyses. For work involving toxics, provide assistance in both the pollutant specific and the biomonitoring approaches and whole effluent toxicity.
  • Ensure that appropriate quality assurance/quality control procedures are used for all Regional and State water quality data and for all data used in Regional decision making including data reported by permittees.
  • Perform Regional water quality assessments primarily based on State data, as needed to prepare Environmental Management Reports.
  • Ensure that Regional data systems are compatible with and do not unnecessarily duplicate national data systems.

13.USEPA. September, 1980. Guidelines and Specifications for Preparing Quality Assurance Project Plans. QAMS-004/80. Washington, D.C. Back.

14.USEPA. December, 1980. Interim Guidelines and Specifications for Preparing Quality Assurance Plans. QAMS-005/80. Washington, D.C. Back.

15.USEPA. May, 1984. Guidance for Preparation of Combined Work/Quality Assurance Project Plans for Environmental Monitoring. OWRS QA-1. Washington, D.C. Back.

16.50 FR 1777, January 11, 1985 and 40 CFR 130. Back.

17.CWA section 303(d)(1) Back.

18.See Scott Decision: Scott v. Hammond, 741 F.2d 992(7th Cir. 1984) Back.

19.40 CFR 130.7(d) Back.

20.40 CFR 122, 123, 130; Surface Water Toxics Control Program. Back.

Table of Contents Chapter 1 Chapter 2 Chapter 3
Chapter 4 Appendix A Appendix B Appendix C
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