Phase II MS4s

A Phase II MS4 is any MS4 not already covered by the Phase I permit as a medium or large MS4. Phase II MS4s are designated if any parts or the entire MS4 is located in an urban area (UA) as defined by the U.S. Bureau of the Census (based on the latest decennial census). 

MS4s that are located outside of the UA may also have potential for being designated by DEP in accordance with Rule 62-624.800, F.A.C.

Phase II MS4 Permit Requirements

A generic permit is a general permit issued by DEP under the authority of Section 403.0885, F.S., which is the provision authorizing the state to implement the NPDES Stormwater Program.

The NPDES Two-Step Generic Permit for Discharge of Stormwater from Phase II MS4s (DEP Document 62-621.300 (7)(a)) was updated in 2021, with minor technical changes made in July 24, 2023.

Operators of a regulated MS4 are required to:

• Reduce the discharge of pollutants to the "Maximum Extent Practicable" (MEP)
• Protect water quality
• Satisfy the water quality requirement of the Clean Water Act
• Address Total Maximum Daily Loads (TMDLs) for regulated MS4s that discharge into TMDL water bodies.

Minimum Control Measures

The Generic Permit requires regulated MS4 operators to develop and implement a Stormwater Management Program (SWMP) that includes six minimum control measures and measurable goals for evaluating program effectiveness.

1. Public Education and Outreach
2. Public Participation/Involvement
3. Illicit Discharge Detection and Elimination
4. Construction Site Stormwater Runoff Control
5. Post-Construction Stormwater Management in New Development and Redevelopment
6. Pollution Prevention/Good Housekeeping for Municipal Operations

Annual reports

During the first 5-year term of permit coverage, operators of regulated Phase II MS4s must submit reports annually. Reports are due within six months of the anniversary of the date of permit coverage.

In subsequent terms, the operator must submit reports in years two and four, unless otherwise requested by DEP.

Submit the Annual Reports using the rule form under which the operator received coverage:

1. Phase II MS4 Annual Report Form for coverage under the 2003 GP.
2. DEP Form 62-621.300(7)(d) for coverage under the 2021 GP.

Obtaining Permit Coverage Under the Generic Permit

Newly designated regulated Phase II MS4 operators are required to apply for coverage within one year of the date of the designation notice.

Operators with existing permits are required to apply for coverage 180 days prior to expiration of permit coverage.

1. Review the NPDES Two-Step Generic Permit for Discharge of Stormwater from Phase II MS4s (DEP Document 62-621.300 (7)(a))
2. Complete a Notice if Intent (NOI) (DEP Form 62-621.300(7)(b)) and SWMP (Appendix A of the NOI)
3. Submit the signed NOI via mail or fax, and applicable fees (as required by Rule 62.4.050, F.A.C.) via check or through the DEP Business Portal.

NPDES Stormwater Program 
2600 Blair Stone Road, MS 3585
Tallahassee, FL 32399-2400

Fax: 850-245-7524 or (Toll Free) 844-273-0222

Note: Until the Department publishes an electronic application system, signed NOIs must be submitted via mail or fax.

Frequently Asked Questions (FAQs): Provides answers to the most commonly posed questions to DEP regarding the Phase II MS4 permit.