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Corner of tabFlorida's NPDES Stormwater Program

Program for Regulated Small MS4s - Who's Covered

 

Only a select subset of Phase II MS4s, referred to as "regulated Phase II" MS4s, will likely be covered under Phase II of Florida's NPDES stormwater program and required to obtain an NPDES stormwater permit. Phase ll MS4s are all MS4s not regulated under Phase I as medium or large MS4s. This includes federally-operated systems which were not included in the Phase I large and medium MS4 definitions, and therefore, were not regulated.

Regulated Phase II MS4s are MS4s brought into the program in one of two ways:
 

  1. Automatic Designation

If any part of or your entire MS4 is located in urbanized area boundaries as defined by the U.S. Bureau of the Census (based on the latest decennial census) then your MS4 will be automatically designated and required to seek permit coverage.

An urbanized area (UA) is a central place (or places) and the adjacent densely surrounding territory that together has a minimum residential population of 50,000 and a minimum average density of 1,000 people/square mile. All UA calculations and mapping are done by the U.S. Bureau of the Census.

Remember: The determination of which MS4s are automatically designated as regulated Phase II MS4s is based SOLEY on the boundaries of U.S. Bureau of the Census urbanized areas –not political boundaries (unlike the Phase I MS4 program). 

To determine if your MS4 is included within a UA:

    • Check these maps to determine if your boundaries and MS4 is located within the 2010 Urbanized Area Boundaries.  View a list of the cities and counties that have been identified as Potential Regulated Phase II MS4s based on the 2010 Census that must file by June 1, 2014. This includes those entities that may qualify for a waiver.  Federal regulations (40 CFR 122.32) establish provisions to waive designated MS4s from permit coverage as follows:
      1. The NPDES permitting authority may waive permit coverage if your MS4 serves a population of less than 1,000 within the urbanized area and you meet the following criteria:
        •  Your system is not contributing substantially to the pollutant loadings of a physically interconnected MS4 that is regulated by the NPDES storm water program; and
        •  If you discharge any pollutant(s) that have been identified as a cause of impairment of any water body to which you discharge, storm water controls are not needed based on wasteload allocations that are part of an EPA approved or established “total maximum daily load” (TMDL) that addresses the pollutant(s) of concern.
      2.  The NPDES permitting authority may waive permit coverage if your MS4 serves a population under 10,000 and you meet the following criteria:
        •  The permitting authority has evaluated all waters of the U.S., including small streams, tributaries, lakes, and ponds, that receive a discharge from your MS4;
        •  For all such waters, the permitting authority has determined that storm water controls are not needed based on wasteload allocations that are part of an EPA approved or established TMDL that addresses the pollutant(s) of concern or, if a TMDL has not been developed or approved, an equivalent analysis that determines sources and allocations for the pollutant(s) of concern;
        •  For the purpose of this paragraph (e), the pollutant(s) of concern include biochemical oxygen demand (BOD), sediment or a parameter that addresses sediment (such as total suspended solids, turbidity or siltation), pathogens, oil and grease, and any pollutant that has been identified as a cause of impairment of any water body that will receive a discharge from your MS4; and
        • The permitting authority has determined that future discharges from your MS4 do not have the potential to result in exceedances of water quality standards, including impairment of designated uses, or other significant water quality impacts, including habitat and biological impacts.
    • Guidance for locating MS4s within 1990 Urbanized Area Boundaries - Refer to the list of Regulated Phase II Small MS4s in Florida. This list contains cities and counties not currently regulated under Phase I, but are located either fully or partially within a UA boundary based on 1990 and 2000 Census data.
    • Additionally, refer to the Bureau of Census Urbanized Area boundary maps based on the 2000 Census results.  View a list of the cities and counties that have been identified as potential Potential Regulated Phase II MS4s that must file by June 1, 2004.
    • Furthermore, entities such as military bases, prison complexes, universities, and highway departments that operate an MS4 within a UA are also subject to the permitting regulations but are not individually listed. It is important to keep in mind that, since counties and city political boundaries may be located both within and outside a UA boundary, only portions of your MS4 may be located within the UA and, therefore, subject to permitting requirements.
  1. Designation by DEP

DEP was required to develop a set of designation criteria to use for the evaluation of all Phase ll MS4s, located outside of UAs which are include in Section 62-624.800(2), F.A.C.  The public may petition the Department to designate a Phase II MS4 as a regulated MS4 by using the designation criteria.  


For more information, send us an e-mail
NPDES Stormwater Program
2600 Blair Stone Road  Mail Station 3585
Tallahassee, FL, 32399
Phone (850) 245-7522

Last updated: January 24, 2013

  2600 Blair Stone Road M.S. 3500   Tallahassee, Florida 32399   850-245-8336 (phone) / 850-245-8356 (fax) 
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