Stormwater Permit Basics


In 1990, the U.S. Environmental Protection Agency (EPA) adopted federal regulations requiring cities with more than 100,000 population to obtain a “Phase I” stormwater permit. The purpose of the permit was to address pollutants in large urban areas that enter local waterways. The Phase I regulations also addressed 11 categories of “industrial activities” including construction that disturbs five or more acres of land.

In 1999, EPA adopted “Phase II” stormwater regulations that required smaller cities, mostly having “Urbanized Area,” along with other cities designated by the permitting authority, to obtain a Phase II stormwater permit. The 1999 regulations also addressed construction between one and five acres. A list and map of all municipal Phase II permittees in Oklahoma can be found on the Permittees in Oklahoma page.

In Oklahoma, the two Phase I cities (Tulsa and Oklahoma City) both have individual permits, while all Phase II cities and counties have General Permits under the state’s “General Permit (OKR04) Phase II Small Municipal Separate Storm Sewer System.” The permitting authority in Oklahoma is the Oklahoma Department of Environmental Quality (ODEQ). EPA Region VI has delegated permitting authority to ODEQ, but EPA maintains final authority over the program.

For permit compliance, each Phase II permittee must address the following six categories of activities, called “Minimum Control Measures”:
1. Public Education and Outreach
2. Public Participation and Involvement
3. Illicit Discharge Detection and Elimination
4. Construction Site Runoff Control
5. Post-Construction Runoff Control
6. Pollution Prevention and Good Housekeeping

Urban pollution is better characterized as “non-point source” pollution, that is, emanating from a diffuse variety of sources not easily recognized or controlled. However, the federal and state stormwater regulations were placed within 40 CFR Part 122, the regulations for point source discharges such as wastewater treatment plants. This creates a special challenge to permittees to control urban non-point source pollution as point source discharges.

Another challenge facing municipal permittees is developing strategies to identify and control pollutants from sources that are difficult to manage, such as wildlife, residential properties, automobiles, and careless or irresponsible disposal of wastes directly into stormdrains and creeks. The stormwater program relies upon public education to encourage changes in behavior to reduce urban pollution.


There are changes ahead for the stormwater permit program. EPA is considering adopting sweeping new rulemaking in the near future that could add new permittees, mandate national standards for controlling runoff volumes from new development and redevelopment, and provide for strategies to implement Low Impact Development (LID) and other pollution source-control practices. ODEQ will finalize its 5-year revisions to OKR04 in the near future. This will bring on additional permittees and increase requirements on all permittees. And all general permits in Oklahoma are incorporating enhanced requirements addressing protected species, specially protected waters and 303(d) listed impaired waterbodies.