In response to the 1987 Amendments to the Clean Water Act by Congress, the Environmental Protection Agency developed Phase I of the National Pollutant Discharge Elimination System (NPDES) in 1990. Phase I regulations address stormwater runoff in medium and large communities, identified 11 industrial categories required to obtain permits (with some exemptions), and addressed statewide land disturbance on five acres or greater. 

In total, 11 industrial categories covering 30 sectors of activity, as described in the Standard Industrial Classification (SIC) system, are required to obtain stormwater discharge permits as outlined in both state and federal regulations. Recently a new more detailed classification system, the North American Industry Classification System, was established. Facilities review either system to choose one code based on their primary type of activity or income source. In lieu of a permit, if a facility has all industrial activities not exposed to stormwater, they may request a no exposure certification. 

EPA delegated authority for the NPDES permitting program to the Missouri Department of Natural Resources. Under this authority, Missouri published its own stormwater regulations (10 CSR 20-6.200) for the first time in 1992.

USEPA published the national Phase II Stormwater Rule in the Federal Register Dec. 8, 1999. Phase II regulations expanded the program to include smaller communities covered under municipal stormwater and land disturbance on one acre or greater. Also since March 10, 2003, municipally operated industries exempted by the Intermodal Surface Transportation Efficiency Act of 1991 were required to obtain permit coverage. Provisions within Intermodal Surface Transportation Efficiency Act temporarily delayed the deadline for Phase I sources (industrial activities with the exception of power plants, airports, and uncontrolled sanitary landfills) operated by municipalities with populations of less than 100,000 people to obtain an NPDES stormwater discharge permit to allow additional time to comply with requirements.

The Water Pollution Control Branch issues permits for the discharge of regulated stormwater. Many of these permits are written to be site-specific to reflect the unique nature of stormwater or receiving water. These permits usually have a five-year cycle. As a permit expires, it is re-drafted, modified if needed, then placed on public notice for 30 days to seek comments on the proposed draft. When the 30-day notice period expires, comments are reviewed and the permit is issued with needed changes or modified and re-noticed to resolve any concerns.

Master General Permits

General permits (as opposed to site-specific permits) are issued to multiple locations where activities are similar enough to be covered by a single set of requirements. For stormwater discharges, these permits are identified by the prefixes MO-R, which appear in the permit numbers. The conditions in master general permit templates are placed on 30-day public notice for comments prior to being issued to applicants. After finalization, a general permit cannot be modified. All facilities receiving a general permit must adhere to the conditions contained in the general permit until it expires or until the facility obtains a site-specific permit. General permits for chemical manufacturing, fabricated structured metal, foundries and wood treaters are required to be placed on public notice prior to issuance to a new facility. 

Permit Effective Date Expiration Date Description Additional Documents
MO-R040000 Phase II Municipal Separate Storm Sewer Systems

Discharges from Regulated Phase II Municipal Separate Storm Sewer Systems

MO-R04C000 Phase II MS4 Comprehensive

Discharges from Regulated Phase II Municipal Separate Storm Sewer Systems

MO-R100000 Land Disturbance by City or County

Construction or land disturbance activity(e.g., clearing, grubbing, excavating, grading, and other activity that results in the destruction of the root zone) that are performed by or under contract to a city, county or other governmental jurisdiction that has a Stormwater control program for land disturbance activities that has been approved by the Missouri Department of Natural Resources.
 

MO-R130000 Textile and Apparel/ Printing and Publishing
Stormwater discharges from production of paper and allied products, textiles and apparel products, and, printing and publishing operations, and paper-only recycling, food and kindred products manufacturing operations.
MO-R203000 Fabricating Metal, Light Industrial
Ferrous and Nonferrous foundries, casting, extrusion, rolling, galvanizing and finishing, structural steel production, light metal fabrication, electrical equipment manufacturing. (For SIC Codes see Page Two)
MO-R22A000 Lumber and Wood Primary
SIC #24XX and 25XX
Stormwater run-off discharges from Primary Lumber and Wood Products Industries.
MO-R22B000 Wood Treaters
Stormwater runoff from facilities engaged in wood treating operations, including but not limited to SIC code 2491.
MO-R22C000 Lumber and Wood (Secondary)
Stormwater runoff from facilities engaged in secondary processing and manufacturing of lumber and wood products.
MO-R23A000 Chemical Manufacturing
Chemical and Lubricant Manufacturing - Stormwater runoff only. (For SIC Codes see page two)
MO-R23D000 Plastics and Rubber Manufacturing
Plastics and Rubber Manufacturing and Molding - Stormwater runoff only and Plastics and Rubber Recycling Operations.
MO-R23E000 Biodiesel Manufacturing
Biodiesel manufacturing facilities that are required to obtain a Stormwater permit.
MO-R240000 Agrichemical Facilities
Agrichemical facilities - Containment water from bulk fertilizer and bulk pesticide facilities.
MO-R60A000 Motor Vehicle Salvage
Motor vehicle salvage yards and scrap metal recycling operations.
MO-R80C000 Motor Freight Transportation
Firms engaged in motor freight, watercraft transportation, warehousing activities and U.S. Postal Service maintenance facilities.
MO-R80F000 Airports
Stormwater runoff from airports that use de-icers or conduct uncovered vehicle or aircraft maintenance, washing or fueling.
MO-R80H000 Solid Waste Transfer
Solid waste transfer stations, SIC 4953; and solid waste recovery facilities, SIC 5093.
MO-RA00000 Construction or Land Disturbance

Construction or land disturbance activity (e.g., clearing, grubbing, excavating, grading and other activities that result in the destruction of the root zone and/or land disturbance activity that is reasonably certain to cause pollution to waters of the state). 

SWPPP

Stormwater Pollution Prevention Plans (SWPPPs)

More information:

BMPs

Precipitation falls on impervious surfaces, such as streets and parking lots, drains to storm sewers and eventually flows to lakes and rivers. Pollutants, such as sediment and chemicals, are carried with the runoff water. As impervious surfaces increase, more water flows off of these surfaces and is delivered faster to receiving waters. Minimizing the mobilization of this material and its impact is the goal of good stormwater runoff management. Using best management practices, such as good housekeeping and in-the-ground structures, can help protect water quality.

No Exposure Certification

A condition of no exposure exists at an industrial facility when all industrial materials and activities are protected by a storm-resistant shelter to prevent exposure to rain, snow, snowmelt and runoff. Industrial materials or activities include, but are not limited to, material handling equipment or activities, industrial machinery, raw materials, intermediate products, by-products, final products or waste (including recyclable) products. Material handling activities include the storage, loading and unloading, transportation or conveyance of any raw material, intermediate product, final product or waste product.

A storm-resistant shelter is not required for the following industrial materials and activities:

  • Storage of drums, barrels, tanks and similar containers that are tightly sealed, provided those containers are not deteriorated and do not leak. “Sealed” means banded or otherwise secured and without operational taps or valves.
  • Adequately maintained vehicles used in material handling
  • Final products, other than products that would be mobilized in stormwater discharges (e.g., rock salt)

For guidance on no exposure certifications as well as a fillable form, please see below:

Guidance