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Subject: Office of Wastewater Management - NPDES Permit Program


NPDES Permit Program - General Information

National Pollutant Discharge Elimination System (NPDES)
Permit Program

The Clean Water Act requires wastewater dischargers to have a permit establishing pollution limits, and specifying monitoring and reporting requirements. National Pollutant Discharge Elimination System (NPDES) permits regulate household and industrial wastes that are collected in sewers and treated at municipal wastewater treatment plants. Permits also regulate industrial point sources and concentrated animal feeding operations that discharge into other wastewater collection systems, or that discharge directly into receiving waters. More than 200,000 sources are regulated by NPDES permits nationwide.

Permits regulate discharges with the goals of 1) protecting public health and aquatic life, and 2) assuring that every facility treats wastewater. To achieve these ends, permits include the following terms and conditions:

Site-specific discharge (or effluent) limits;
Standard and site-specific compliance monitoring and reporting requirements; and
When and if regulated facilities fail to comply with the provisions of their permits, they may be subject to enforcement actions. EPA uses a variety of techniques to monitor permittees' compliance status, including on-site inspections and review of data submitted by permittees.


CONVENTIONAL POLLUTANTS are contained in the sanitary wastes of households, businesses, and industries. These pollutants include human wastes, ground-up food from sink disposals, and laundry and bath waters. Conventional pollutants include:

Fecal Coliform - These bacteria are found in the digestive tracts of humans and animals; their presence in water indicates the potential presence of pathogenic organisms.

Oil and Grease - These organic substances may include hydrocarbons, fats, oils, waxes, and high-molecular fatty acids. Oil and grease may produce sludge solids that are difficult to process.

TOXIC POLLUTANTS are particularly harmful to animal or plant life. They are primarily grouped into organics (including pesticides, solvents, polychlorinated biphenyls (PCBs), and dioxins) and metals (including lead, silver, mercury, copper, chromium, zinc, nickel, and cadmium).

NONCONVENTIONAL POLLUTANTS are any additional substances that are not conventional or toxic that may require regulation. These include nutrients such as nitrogen and phosphorus.


A NPDES Watershed Strategy has been developed to ensure that the NPDES Program protects watersheds as effectively as possible.

OWM developed the NPDES Watershed Strategy with input from States and EPA Regions. The final strategy reflects a first step towards the Office of Water's goal of fully integrating the NPDES permitting program into the Agency's broader Water Protection Approach.

The Watershed Strategy identifies six areas that must be addressed to improve water quality on a watershed basis nationwide, including:

Statewide coordination: Support the development of State-wide basin management frameworks, and coordinate interstate basin efforts to facilitate implementation of the Watershed Protection Approach.

NPDES Permits: Streamline the process for NPDES permit development, issuance, and review, and develop innovative approaches to permitting on a watershed basis where feasible.

Monitoring and assessment: Develop a state-wide monitoring strategy, and establish point-source ambient monitoring requirements.

Programmatic measures and environmental indicators: Revise existing national accountability measures to facilitate implementation of the Watershed Protection Approach.

Public participation: Utilize existing NPDES public participation process in development of watershed protection plans, and seek broad public participation in identifying local environmental goals.

Enforcement: Include emphasis on facilities that discharge to priority basins.

Implementation of the Watershed Strategy is now underway, and will include the completion of assessments of each State's watershed protection activities and needs. OWM will coordinate with other EPA Offices and States to ensure that ongoing program activities take watershed planning into consideration.

Wet Weather

Chief among the NPDES Program's responsibilities is the effective implementation of EPA's wet-weather strategies, including storm water management and the control of combined sewer and sanitary sewer overflows.

NPDES Storm Water Program

Storm water discharges from many sources are largely uncontrolled. For this reason, the mandate of the Storm Water Program is particularly challenging.

Amendments to the Clean Water Act established a two-phased approach to addressing storm water discharges. Phase I, currently being implemented, requires permits for separate storm water systems serving large- and medium-sized communities (those with over 100,000 inhabitants), and for storm water discharges associated with industrial and construction activity involving at least five acres.

To address the large number of industrial dischargers of storm water--at over 100,000 facilities--EPA has developed a strategy with a tiered framework to control the administrative burden while emphasizing reduction in risk to human health and ecosystems.

Phase II, which is currently under development, will address remaining storm water discharges. Ultimately, millions of potential permittees will be covered, including urban areas with populations under 100,000, smaller construction sites, and retail, commercial, and residential activities.

NPDES Program: Combined Sewer Overflows (CSOs)

In April 1994, EPA issued a policy for the control of combined sewer overflows. The policy calls for communities with CSOs to take immediate and long-term actions to address these overflow problems. Measures specified in the policy include proper operation and regular maintenance of sewer systems and CSOs, as well as the public notice in the event of overflows, to ensure that the public receives adequate notification of the impact of this health and environmental hazard.

Despite its rigorous approach to controlling combined sewer overflows, the CSO Control Policy provides communities with the flexibility to develop a workable, cost-effective solution to a major environmental problem. With significant input from key stakeholders, OWM is currently developing guidances to assist communities to implement measures for the control of CSOs as effectively as possible.

NPDES Program: Sanitary Sewer Overflows

EPA is currently in the process of evaluating the extent of sanitary sewer overflows across the country. The Agency will work with the public and with constituent groups across the country to identify and evaluate issues associated with these overflows to protect human health, property, and water quality.