Stormwater: Questions and Answers


Courtesy of Ben Meadows

The whole subject of Stormwater is complicated. Here's a chance for you to check out some of the most frequently asked questions about stormwater . . . and their answers.

What is an NPDES (National Pollutant Discharge Elimination System) permit?

The Clean Water Act prohibits anybody from discharging 'pollutants' through a 'point source' into a 'water of the United States' unless they have an NPDES permit. The permit will contain limits on what you can discharge, monitoring and reporting requirements, and other provisions to ensure that the discharge does not hurt water quality or people's health. In essence, the permit translates general requirements of the Clean Water Act into specific provisions tailored to the operations of each person discharging pollutants.

What is a point source?

The term point source is very broadly defined in the Clean Water Act because it has been through 25 years of litigation. It means any discernable, confined and discrete conveyance, such as a pipe, ditch, channel, tunnel, conduit, discrete fissure, or container. It also includes vessels or other floating craft from which pollutants are or may be discharged. By law, the term 'point source' also includes concentrated animal feeding operations, which are places where animals are confined and fed. By law, agricultural storm water discharges and return flows from irrigated agriculture are not 'point sources'.

What is a water of the United States?

The term 'water of the United States' is also defined very broadly in the Clean Water Act and after 25 years of litigation. It means navigable waters, tributaries to navigable waters, interstate waters, the oceans out to 200 miles, and intrastate waters which are used: by interstate travelers for recreation or other purposes, as a source of fish or shellfish sold in interstate commerce, or for industrial purposes by industries engaged in interstate commerce.

What is a pollutant?

The term pollutant is defined very broadly in the Clean Water Act because it has been through 25 years of litigation. It includes any type of industrial, municipal, and agricultural waste discharged into water. Some examples are dredged soil, solid waste, incinerator residue, sewage, garbage, sewage sludge, munitions, chemical wastes, biological materials, radioactive materials, heat, wrecked or discarded equipment, rock, sand, cellar dirt, and industrial, municipal, and agricultural waste. By law, a pollutant is not sewage or discharges incidental to the normal operations of an Armed Forces vessel, or water, gas, or other material injected into an oil and gas production well.

Do I need an NPDES permit?

It depends on where you discharge pollutants. If you discharge from a point source into waters of the United States, you need an NPDES permit. If you discharge pollutants into a municipal sanitary sewer system, you do not need an NPDES permit, but you should ask the municipality about their permit requirements. If you discharge pollutants into a municipal storm sewer system, you may need a permit depending on what you discharge. You should ask the NPDES permitting authority.

Where do I apply for an NPDES permit?

NPDES permits are issued by states that have obtained EPA approval to issue permits or by EPA Regions in states without such approval. The following map illustrates the states with full, partial, and no NPDES Authority. This file in PDF format provides the status of states NPDES Programs.

How are the conditions in NPDES permits enforced by EPA and the States?

There are various methods used to monitor NPDES permit conditions. The permit will require the facility to sample its discharge and notify EPA and the state regulatory agency of these results. In addition, the permit will require the facility to notify EPA and the state regulatory agency when the facility determines it is not in compliance with the requirements of a permit. EPA and state regulatory agencies also will send inspectors to companies in order to determine if they are in compliance with the conditions imposed under their permits.

Federal laws provide EPA and authorized state regulatory agencies with various methods of taking enforcement actions against violators of permit requirements. For Example, EPA and state regulatory agencies may issue administrative orders which require facilities to correct violations and that assess monetary penalties. The laws also allow EPA and state agencies to pursue civil and criminal actions that may include mandatory injunctions or penalties, as well as jail sentences for persons found willfully violating requirements and endangering the health and welfare of the public or environment. Equally important is how the general public can enforce permit conditions. The facility monitoring reports are public documents, and the general public can review them. If any member of the general public finds that a facility is violating its NPDES permit, that member can independently start a legal action, unless EPA or the state regulatory agency has taken an enforcement action.

Typically, how long are NPDEES permits effective?

The Clean Water Act limits the length of NPDES permits to five years. NPDES permits can be renewed (reissued) at any time after the permit holder applies. In addition, NPDES permits can be administratively extended if the facility reapplies more than 180 days before the permit expires, and EPA or the state regulatory agency, which ever issued the original permit, agrees to extend the permit.

What is the National Pollutant Discharge Elimination System (NPDES) Storm Water Program?

Polluted storm water runoff is a leading cause of impairment to the nearly 40 percent of surveyed U.S. water bodies which do not meet water quality standards. Over land or via storm sewer systems, polluted runoff is discharged, often untreated, directly into local water bodies. When left uncontrolled, this water pollution can result in the destruction of fish, wildlife, and aquatic life habitats: a loss in aesthetic value; and threats to public health due to contaminated food, drinking water supplies, and recreational waterways.

Mandated by Congress under the Clean Water Act, the NPDES Storm Water Program is a comprehensive two-phased national program for addressing the non-agricultural sources of storm water discharges which adversely affect the quality of our nation's waters. The Program uses the National Pollutant Discharge Elimination System (NPDES) permitting mechanism to require the implementation of controls designed to prevent harmful pollutants from being washed by storm water runoff into local water bodies.

What is a Municipal Separate Storm Sewer System (MS4)?

The regulatory definition of an MS4 (40 CFR 122.26(b)(8)) is ' a conveyance of system of conveyances (including roads with drainage systems, municipal streets, catch basins, curbs, gutters, ditches, man-made channels, or storm drains): (i) Owned or operated by a state, city, town, borough, county, parish, district, association, or other public body (created to or pursuant to state law)…including special districts under state law such as a sewer district, flood control district or drainage district, or similar entity, or an Indian tribe or an authorized Indian tribal organization, or a designated and approved management agency under section 208 of the Clean Water Act that discharges into waters of the United States. (ii) Designed or used for collecting or conveying storm water; (iii) Which is not a combined sewer; and (iv) Which is not part of a Publicly Owned Treatment Works (POTW) as defined at 40 CFR 122.2.'

In practical terms, operators of MS4s can include municipalities and local sewer districts, state and federal departments of transportation, universities, hospitals, military bases, and correctional facilities. The Storm Water Phase II Rule added federal systems, such as military bases and correctional facilities by including them in the definition of small MS4s.

Who is regulated under the Storm Water Phase II Final Rule?

The rule automatically regulates two classes of storm water dischargers on a nationwide basis: Operators of small MS4s located in 'urbanized areas' as defined by the Bureau of Census and operators of construction activities that disturb equal to or greater than 1 and less than 5 acres of land. Additional small MS4s (outside urbanized areas) and construction sites (disturbing less than one acre of land), along with other sources which are a significant contributor of pollutants to waters of the U.S., may be brought into the NPDES Storm Water Program by the NPDES permitting authority.

The rule also exclude from the NPDES program storm water discharges from industrial facilities that have 'no exposure' of industrial activities or materials to storm water. This exclusion does require facilities to complete, sign, and submit a no exposure certification to the permitting authority once every five years.

When will I need to get a permit under the Storm Water Phase II regulations?

Operators of Phase II regulated small MS4s and small construction activity are required to apply for NPDES permit coverage by March 10, 2003. The agency which issues your NPDES permit could set an earlier deadline for permit coverage.

Is a permit required for regulated MS4s?

Yes. A National Pollutant Discharge Elimination System (NPDES) permit must be obtained by the operator of an MS4 covered by the NPDES Storm Water Program.

Which MS4s are regulated by the NPDES Storm Water Program?

For regulatory purposes, EPA's NPDES Storm Water Program regulates 'medium,' 'large,' and 'regulated small MS4s.'

A medium MS4 is a system that is located in an incorporated place or country with a population between 100,000-249,999.

A large MS4 is a system that is located in an incorporated place or country with a population of 250,000 or more.

In addition, some MS4s that serve a population below 100,000 gave been brought into the Phase I program by an NPDES permitting authority and are treated as medium or large MS4s, independent of the size of the population served.

A small MS4 is any MS4 that is not covered by Phase I of the NPDES Storm Water Program as a medium or large MS4, i.e., any MS4 that does not currently have an NPDES storm water permit. (There is no population threshold associated with this definition).

A regulated small MS4 is any small MS4 located in an 'urbanized area' (UA), as defined by the Bureau of Census, or located outside of a UA and brought into the program by the NPDES permitting authority.

What is required of the regulated entities under the NPDES Storm Water Program?

The regulated entities must obtain coverage under an NPDES storm water permit and implement storm water pollution prevention plans (SWPPPs) or storm water management programs (both using best management practices (BMPs)) that effectively reduce or prevent the discharge of pollutants into receiving waters.

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