Biennial Assessment 2024-2026 Draft Study List and Study List Removals List
(November 7, 2025)
The department announces a public meeting to present and receive public comments on the Biennial Assessment 2024-2026 draft assessment lists of waterbodies and water segments. The meeting is scheduled for November 19, 2025, 10 a.m. to be held virtually via GoToWebinar.
The department will accept written comments on the draft assessment lists through January 9, 2026. Written comments should be directed to: Jessica Mostyn at Jessica Mostyn@FloridaDEP.gov, or Mail Station #3555, 2600 Blair Stone Road, Tallahassee, Florida 32399-2400.
The draft assessment lists were developed pursuant to Chapter 62-303, Florida Administrative Code (F.A.C.), and include all 29 basins in the state. In addition to the draft assessment lists in spreadsheet format, an interactive map titled "Biennial Assessment 2024-2026 Draft Lists" is available that shows the geographic location of the waterbodies and waterbody segments by WBID that are proposed for addition to the Verified List, Delist List, Study List, or Study List Removals List. These assessment lists were produced with water quality and biological data that were received by the department as of July 18, 2024, and included in the IWR Run 66 Database. They also incorporate station-WBID assignment updates, WBID classification updates, and data exclusions based on a preliminary evaluation by department staff.
For best results, print on legal size paper (8.5 x 14).
A Class I, II, III, or Class III-Limited water shall be placed on the Study List in assessment category 4d if:
- It has a statistically-significant (at the 95 percent confidence level) increasing temporal trend in annual geometric means for TN, TP, nitrate-nitrite, or chlorophyll a and there is a reasonable expectation that the water will become impaired within 10 years.
- It does not achieve the Biological Health Assessment provisions in Rule 62-303.430, F.A.C., but a cause has not been identified.
- It is verified as not meeting the dissolved oxygen criterion pursuant to the verified list requirements, but a cause has not been identified. For streams meeting the definition in subsection 62-302.200(36), F.A.C., that do not have a site specific numeric interpretation of the narrative nutrient criterion, the nutrient thresholds in subparagraph 62-302.531(2)(c)2., F.A.C., are exceeded based on data from the last 7.5 years and insufficient Biological Health Assessment, chlorophyll a, or other response variable data are available to fully assess achievement of the nutrient provisions in paragraph 62-302.531(2)(c), F.A.C.
- There are fewer than twenty samples for a bacteriological water quality criterion, but there are five or more samples that do not meet an applicable water quality criterion based on data from at least five temporally independent sampling events;
- It is verified as not meeting the bacteriological water quality criterion pursuant to Part IV of Chapter 62-303, F.A.C., but the department determines that additional study is needed to evaluate whether the exceedances are due to natural sources given the predominance of natural land uses in the watershed or based on information submitted to the department; or
- It exceeds a generally applicable criterion, but the department receives a SSAC petition pursuant to Rule 62-302.800, F.A.C., and additional time is needed to review and process the petition.
A Class I, II, III, or Class III-Limited water shall be placed on the Study List in assessment category 4e if:
- Pollution control mechanisms are in place or planned that meet the requirements of subsections 62-303.600(1) and (3), F.A.C., but there is uncertainty when water quality standards will be attained and the waterbody segment requires additional study.
Waterbodies placed into assessment category 4d will be targeted for strategic monitoring before the next cycle of assessments for that waterbody. For waterbodies placed into assessment category 4e, the department shall evaluate progress towards attainment of water quality standards. Please note that the department will submit waterbodies included on the Study List to EPA Region IV as water quality-limited segments for inclusion on Florida’s 303(d) list in accordance with the Clean Water Act.
Waterbody-parameter combinations that no longer meet the listing requirements for the Study List, as identified in Rule 62-303.390, F.A.C., are submitted to EPA for removal from the 303(d) List. There are several reasons for requesting removal from the 303(d) List including, but not limited to, more recent or accurate data, flaws in the original analysis, site-specific data or information to support natural conditions, and changes in water quality conditions.
