DEP 2007          INDENTIFICATION OF IMPAIRED SURFACE WATERS     62‐303 

CHAPTER 62-303 

IDENTIFICATION OF IMPAIRED SURFACE WATERS 

TABLE OF CONTENTS 

PART I 

GENERAL 

62-303.100 SCOPE AND INTENT. ................................................................................................... 2

62-303.150 RELATIONSHIP BETWEEN PLANNING AND VERIFIED LISTS................................ 3

62-303.200 DEFINITIONS................................................................................................................. 3

62-303.300 METHODOLOGY TO DEVELOP THE PLANNING LIST.............................................. 5

62-303.310 EVALUATION OF AQUATIC LIFE USE SUPPORT..................................................... 5

62-303.320 AQUATIC LIFE-BASED WATER QUALITY CRITERIA ASSESSMENT. .................... 6

62-303.330 BIOLOGICAL ASSESSMENT..................................................................................... 10

62-303.340 TOXICITY. (REPEALED)............................................................................................. 11

62-303.350 INTERPRETATION OF NARRATIVE NUTRIENT CRITERIA. ................................... 11

62-303.351 NUTRIENTS IN STREAMS.......................................................................................... 12

62-303.352 NUTRIENTS IN LAKES. .............................................................................................. 12

62-303.353 NUTRIENTS IN ESTUARIES AND OPEN COASTAL WATERS. .............................. 12

62-303.360 PRIMARY CONTACT AND RECREATION USE SUPPORT...................................... 13

62-303.370 FISH AND SHELLFISH CONSUMPTION USE SUPPORT. ....................................... 13

62-303.380 DRINKING WATER USE SUPPORT AND PROTECTION OF HUMAN HEALTH..... 14

62-303.400 METHODOLOGY TO DEVELOP THE VERIFIED LIST.............................................. 15

62-303.410 DETERMINATION OF AQUATIC LIFE USE SUPPORT. ........................................... 15

62-303.420 AQUATIC LIFE-BASED WATER QUALITY CRITERIA ASSESSMENT. .................. 15

62-303.430 BIOLOGICAL IMPAIRMENT. ...................................................................................... 18

62-303.440 TOXICITY. (REPEALED)............................................................................................. 19

62-303.450 INTERPRETATION OF NARRATIVE NUTRIENT CRITERIA. ................................... 19

62-303.460 PRIMARY CONTACT AND RECREATION USE SUPPORT...................................... 20

62-303.470 FISH AND SHELLFISH CONSUMPTION USE SUPPORT. ....................................... 21

62-303.480 DRINKING WATER USE SUPPORT AND PROTECTION OF HUMAN HEALTH..... 22

62-303.500 PRIORITIZATION......................................................................................................... 22

62-303.600 EVALUATION OF POLLUTION CONTROL MECHANISMS...................................... 23

62-303.700 LISTING CYCLE. ......................................................................................................... 23

62-303.710 FORMAT OF VERIFIED LIST AND VERIFIED LIST APPROVAL. ............................ 24

62-303.720 DELISTING PROCEDURE. ......................................................................................... 24

62-303.810 IMPAIRMENT OF INTERSTATE AND TRIBAL WATERS. ........................................ 27

Effective 9-4-07 Page 1 
DEP 2007          INDENTIFICATION OF IMPAIRED SURFACE WATERS     62‐303 

PART I 

GENERAL 

 62-303.100 Scope and Intent. 

 (1) This chapter establishes a methodology to identify surface waters of the state that will 

be included on the state’s planning list of waters that will be assessed pursuant to subsections 

403.067(2) and (3), Florida Statutes (F.S.). It also establishes a methodology to identify impaired 

waters based on representative data that will be included on the state’s verified list of impaired 

waters, for which the Department will calculate Total Maximum Daily Loads (TMDLs), pursuant to 

subsection 403.067(4), F.S., and which will be submitted to the United States Environmental 

Protection Agency (EPA) pursuant to paragraph 303(d)(1) of the Clean Water Act (CWA). 

 (2) Subsection 303(d) of the CWA and section 403.067, F.S., describe impaired waters as 

those not meeting applicable water quality standards, which is a broad term that includes 

designated uses, water quality criteria, the Florida antidegradation policy, and moderating 

provisions. However, as recognized when the water quality standards were adopted, many water 

bodies naturally do not meet one or more established water quality criteria at all times, even though 

they meet their designated use. It is not the intent of this chapter to include waters that do not meet 

otherwise applicable water quality criteria solely due to natural conditions or physical alterations of 

the water body not related to pollutants. Similarly, it is not the intent of this chapter to include waters 

where designated uses are being met and where water quality criteria exceedances are limited to 

those parameters for which permitted mixing zones or other moderating provisions (such as sitespecific alternative criteria) are in effect. Waters that do not meet otherwise applicable water quality 

standards due to natural conditions or to pollution not related to pollutants shall be noted in the 

state’s water quality assessment prepared under subsection 305(b) of the CWA [305(b) Report]. 

 (3) This chapter is intended to evaluate attainment of water quality standards as set forth 

in Chapter 62-302, F.A.C., for the purposes of identifying water bodies or segments for which 

TMDLs will be established. It is the intent of this chapter to establish requirements that would apply 

solely for purposes of assessment and listing under CWA sections 303(d) and 305(b). However, it 

is not the intent of this chapter to establish requirements for other purposes under Florida law. In 

cases where this chapter relies on numeric indicators of ambient water quality as part of the 

methodology for determining whether existing narrative criteria are being met, these numeric values 

are intended to be used only in the context of developing a planning list and identifying an impaired 

water pursuant to this chapter. As such, exceedances of these numeric values shall not, by 

themselves, constitute violations of Department rules that would warrant enforcement action. 

 (4) Nothing in this rule is intended to limit any actions by federal, state, or local agencies, 

affected persons, or citizens pursuant to other rules or regulations. 

 (5) Pursuant to section 403.067, F.S., impaired waters shall not be listed on the verified 

list if reasonable assurance is provided that, as a result of existing or proposed technology-based 

effluent limitations and other pollution control programs under local, state, or federal authority, they 

will attain water quality standards in the future and reasonable progress towards attainment of water 

quality standards will be made by the time the next 303(d) list is scheduled to be submitted to EPA. 

Specific Authority 403.061, 403.067 FS. Law Implemented 403.021(11), 403.062, 403.067 FS. 

History - New 6-10-02, Amended 12-11-06. 

Effective 9-4-07 Page 2 
DEP 2007          INDENTIFICATION OF IMPAIRED SURFACE WATERS     62‐303 

 62-303.150 Relationship Between Planning and Verified Lists. 

 (1) The Department shall follow the methodology in Section 62-303.300 to develop a 

planning list pursuant to subsection 403.067(2), F.S. As required by subsection 403.067(2), F.S., 

the planning list shall not be used in the administration or implementation of any regulatory program, 

and shall be submitted to EPA for informational purposes only. Waters on this planning list will be 

assessed pursuant to subsection 403.067(3), F.S., as part of the Department’s watershed 

management approach. During this assessment, the Department shall determine whether the water 

body is impaired and whether the impairment is due to pollutant discharges using the methodology 

in Part III. The resultant verified list of impaired waters, which is the list of waters for which TMDLs 

will be developed by the Department pursuant to subsection 403.067(4), will be adopted by 

Secretarial Order and will be subject to challenge under subsection 120.569 and 120.57, F.S. Once 

adopted, the list will be submitted to the EPA pursuant to paragraph 303(d)(1) of the CWA. 

 (2) Consistent with state and federal requirements, opportunities for public participation, 

including workshops, meetings, and periods to submit comments on draft lists, will be provided as 

part of the development of planning and verified lists. 

Specific Authority 403.061, 403.067 FS. Law Implemented 403.062, 403.067 FS. History - New 6-

10-02, Repromulgated 1-2-07. 

 62-303.200 Definitions. 

As used in this chapter: 

 (1) “Bioassessment” shall mean a BioRecon, Lake Condition Index, or Stream Condition 

Index. 

 (2) “BioRecon” shall mean a biological evaluation conducted in accordance with standard 

operating procedures (SOPs) FT 3000, FS 7410, and LT 7100, as promulgated in Rule 62-160.800 

F.A.C. 

 (3) “Clean techniques” shall mean those applicable field sampling procedures and 

analytical methods referenced in “Method 1669: Sampling Ambient Water for Trace Metals at EPA 

Water Quality Criteria Levels, July 1996, USEPA, Office of Water, Engineering and Analysis 

Division, Washington, D.C.,” which is incorporated by reference. 

 (4) “Department” or “DEP” shall mean the Florida Department of Environmental 

Protection. 

 (5) “Designated use” shall mean the present and future most beneficial use of a body of 

water as designated by the Environmental Regulation Commission by means of the classification 

system contained in Chapter 62-302, F.A.C. 

 (6) “Estuary” shall mean predominantly marine regions of interaction between rivers and 

nearshore ocean waters, where tidal action and river flow mix fresh and salt water. Such areas 

include bays, mouths of rivers, and lagoons. 

 (7) “Impaired water” shall mean a water body or water body segment that does not meet 

its applicable water quality standards as set forth in Chapters 62-302 and 62-4, F.A.C, as 

determined by the methodology in Part III of this chapter, due in whole or in part to discharges of 

pollutants from point or nonpoint sources. 

 (8) “Lake Condition Index” shall mean the benthic macroinvertebrate component of a 

biological evaluation conducted following the procedures outlined in “Development of Lake 

Condition Indexes (LCI) for Florida,” Florida Department of Environmental Protection, July, 2000, 

which is incorporated by reference. 

Effective 9-4-07 Page 3 
DEP 2007          INDENTIFICATION OF IMPAIRED SURFACE WATERS     62‐303 

 (9) “Natural background” shall mean the condition of waters in the absence of maninduced alterations based on the best scientific information available to the Department. The 

establishment of natural background for an altered waterbody may be based upon a similar 

unaltered waterbody or on historical pre-alteration data. 

 (10) “Nuisance species” shall mean species of flora or fauna whose noxious characteristics 

or presence in sufficient number, biomass, or areal extent may reasonably be expected to prevent, 

or unreasonably interfere with, a designated use of those waters. 

 (11) “Open coastal waters” shall mean all gulf or ocean waters that are not classified as 

estuaries or open ocean waters. 

 (12) “Open ocean waters” means all surface waters extending seaward from the most 

seaward natural 90-foot (15-fathom) isobath. Contour lines may be determined from National 

Oceanic and Atmospheric Administration Charts. 

 (13) “Physical alterations” shall mean human-induced changes to the physical structure of 

the water body. 

 (14) “Planning list” shall mean the list of surface waters or segments for which 

assessments will be conducted to evaluate whether the water is impaired and a TMDL is needed, as 

provided in subsection 403.067(2), F.S. 

 (15) “Pollutant” shall be as defined in subsection 502(6) of the CWA. Characteristics of a 

discharge, including dissolved oxygen, pH, or temperature, shall also be defined as pollutants if they 

result or may result in the potentially harmful alteration of downstream waters. 

 (16) “Pollution” shall be as defined in subsection 502(19) of the CWA and subsection 

403.031(2), F.S. 

 (17) “Predominantly marine waters” shall mean surface waters in which the chloride 

concentration at the surface is greater than or equal to 1,500 milligrams per liter. 

 (18) “Reference water” means a waterbody that exhibits a range of physical, chemical and 

biological characteristics approximating the natural background conditions of the same, or similar, 

type of waterbody within an ecologically similar region. A reference water may be representative of 

the water quality and structure and function of biological communities of natural background 

conditions even if there is evidence of limited human disturbance in the waterbody or watershed, as 

long as anthropogenic sources do not produce a significant measurable or predicted effect on the 

parameter of concern in the waterbody. 

 (19) “Secretary” shall mean the Secretary of the Florida Department of Environmental 

Protection. 

(20) “Spill” shall mean a short-term, unpermitted discharge to surface waters, not to include 

sanitary sewer overflows or chronic discharges from leaking wastewater collection systems. 

(21) “Stream” shall mean a free-flowing, predominantly fresh surface water in a defined 

channel, and includes rivers, creeks, branches, canals, freshwater sloughs, and other similar water 

bodies. 

(22) “Stream Condition Index” shall mean a biological evaluation conducted in accordance 

with SOPs FT 3000, FS 7420, and LT 7200, as promulgated in Rule 62-160.800, F.A.C. 

 (23) “Surface water” means those waters of the State upon the surface of the earth to their 

landward extent, whether contained in bounds created naturally or artificially or diffused. Water from 

natural springs shall be classified as surface water when it exits from the spring onto the earth’s 

surface. 

(24) “Total maximum daily load” (TMDL) for an impaired water body or water body segment 

shall mean the sum of the individual wasteload allocations for point sources and the load allocations 

Effective 9-4-07 Page 4 
DEP 2007          INDENTIFICATION OF IMPAIRED SURFACE WATERS     62‐303 

for nonpoint sources and natural background. Prior to determining individual wasteload allocations 

and load allocations, the maximum amount of a pollutant that a water body or water segment can 

assimilate from all sources without exceeding water quality standards must first be calculated. A 

TMDL shall include either an implicit or explicit margin of safety and a consideration of seasonal 

variations. 

(25) “Trophic State Index” or “TSI” means the trophic state index for lakes, which is based 

on lake chlorophyll a, Total Nitrogen, and Total Phosphorus levels, and is calculated following the 

procedures outlined on pages 86 and 87 of the State’s 1996 305(b) report, which are incorporated 

by reference. 

 (26) “Verified list” shall mean the list of impaired water bodies or segments for which 

TMDLs will be calculated, as provided in subsection 403.067(4), F.S., and which will be submitted to 

EPA pursuant to paragraph 303(d)(1) of the CWA. 

 (27) “Water quality criteria” shall mean elements of State water quality standards, 

expressed as constituent concentrations, levels, or narrative statements, representing a quality of 

water that supports the present and future most beneficial uses. 

 (28) “Water quality standards” shall mean standards composed of designated present and 

future most beneficial uses (classification of waters), the numerical and narrative criteria applied to 

the specific water uses or classification, the Florida antidegradation policy, and the moderating 

provisions (mixing zones, site-specific alternative criteria, and exemptions) contained in Chapter 62-

302, F.A.C., and in Chapter 62-4, F.A.C., adopted pursuant to Chapter 403, F.S. 

 (29) “Water segment” shall mean a portion of a water body that the Department will assess 

and evaluate for purposes of determining whether a TMDL will be required. Water segments 

previously evaluated as part of the Department’s 1998 305(b) Report are depicted in the map titled 

“Water Segments of Florida,” which is incorporated by reference. 

 (30) “Waters” shall be those surface waters described in Section 403.031(13), Florida 

Statutes. 

Specific Authority 403.061, 403.067 FS. Law Implemented 403.062, 403.067 FS. History - New 6-

10-02, Amended 12-11-06. 

PART II 

THE PLANNING LIST 

62-303.300 Methodology to Develop the Planning List. 

 (1) This part establishes a methodology for developing a planning list of waters to be 

assessed pursuant to subsections 403.067(2) and (3), F.S. 

 (2) Waters on the list of water segments submitted to EPA in 1998 that do not meet the 

data sufficiency requirements for the planning list shall nevertheless be included in the state’s initial 

planning list developed pursuant to this rule. 

Specific Authority 403.061, 403.067 FS. Law Implemented 403.062, 403.067 FS. History - New 6-

10-02, Amended 12-11-06. 

 62-303.310 Evaluation of Aquatic Life Use Support. 

A Class I, II, or III water shall be placed on the planning list for assessment of aquatic life use 

support (propagation and maintenance of a healthy, well-balanced population of fish and wildlife) if, 

based on sufficient quality and quantity of data, it: 

Effective 9-4-07 Page 5 
DEP 2007          INDENTIFICATION OF IMPAIRED SURFACE WATERS     62‐303 

 (1) Exceeds applicable aquatic life-based thresholds as outlined in section 62-303.320, 

F.A.C. 

 (2) Does not meet biological assessment thresholds for its water body type as outlined in 

section 62-303.330, F.A.C., or 

 (3) Exceeds nutrient thresholds as outlined in section 62-303.350, F.A.C. 

Specific Authority 403.061, 403.067 FS. Law Implemented 403.062, 403.067 FS. History - New 6-

10-02, Amended 12-11-06. 

 62-303.320 Aquatic Life-Based Water Quality Criteria Assessment. 

 (1) Water segments shall be placed on the planning list if, using objective and credible 

data, as defined by the requirements specified in this section, the number of samples that do not 

meet an applicable water quality criterion due to pollutant discharges is greater than or equal to the 

number listed in Table 1 for the given sample size. For sample sizes up to 500, waters are placed 

on the planning list when 10% or more of the samples do not meet the applicable criteria with a 

minimum of an 80% confidence level using a binomial distribution. For sample sizes greater than 

500, the Department shall calculate the number of samples not meeting the criterion that are 

needed to list the waterbody with an 80% confidence level for the given sample size using the 

binomial distribution. 

Effective 9-4-07 Page 6 
DEP 2007          INDENTIFICATION OF IMPAIRED SURFACE WATERS     62‐303 

Table 1: Planning List 

Minimum number of samples not meeting an applicable water quality criterion 

needed to put a water on the planning list with at least 80% confidence. 

Sample sizes Sample sizes 

From To 

Are listed if 

they have at 

least this # of 

samples that 

do not meet a 

criterion From To 

Are listed if 

they have at 

least this # of 

samples that 

do not meet a 

criterion 

10 15 3 256 264 31 

16 23 4 265 273 32 

24 31 5 274 282 33 

32 39 6 283 292 34 

40 47 7 293 301 35 

48 56 8 302 310 36 

57 65 9 311 320 37 

66 73 10 321 329 38 

74 82 11 330 338 39 

83 91 12 339 348 40 

92 100 13 349 357 41 

101 109 14 358 367 42 

110 118 15 368 376 43 

119 126 16 377 385 44 

127 136 17 386 395 45 

137 145 18 396 404 46 

146 154 19 405 414 47 

155 163 20 415 423 48 

164 172 21 424 432 49 

173 181 22 433 442 50 

182 190 23 443 451 51 

191 199 24 452 461 52 

200 208 25 462 470 53 

209 218 26 471 480 54 

219 227 27 481 489 55 

228 236 28 490 499 56 

237 245 29 500 500 57 

246 255 30 

Effective 9-4-07 Page 7 
DEP 2007          INDENTIFICATION OF IMPAIRED SURFACE WATERS     62‐303 

 (2) The Department’s Florida Storage and Retrieval (FLASTORET) database, or its 

successors, shall be the primary source of data used for determining whether samples do not meet 

water quality criteria. As required by rule 62-40.540(3), F.A.C., the Department, other state 

agencies, the Water Management Districts, and local governments collecting surface water quality 

data in Florida shall enter the data into FLASTORET within one year of collection. Other sampling 

entities that want to ensure their data will be considered for evaluation should ensure their data are 

entered into FLASTORET. The Department shall consider data submitted to the Department from 

other sources and databases if the data meet the sufficiency and data quality requirements of this 

section. 

 (3) Unless information presented to the Department demonstrates otherwise, data older 

than ten years at the time the water segment is proposed for listing on the planning list are not 

representative of current conditions and shall not be used to develop planning lists, except to 

evaluate historical trends in chlorophyll a or TSIs. Any determinations by the Department to use 

data older than 10 years shall be documented, and the documentation shall include the basis for the 

decision that the data are representative of current conditions. Further, more recent data shall take 

precedence over older data if: 

(a) The newer data indicate a change in water quality and this change is related to 

changes in pollutant loading to the watershed or improved pollution control mechanisms in the 

watershed contributing to the assessed area, or 

(b) The Department determines that the older data do not meet the data quality 

requirements of this section or are no longer representative of the water quality of the segment. The 

Department shall note for the record that the older data were excluded and provide details about 

why the older data were excluded. 

(4) To place a water segment on the planning list using Table 1, a water segment shall 

have a minimum of ten samples for the ten-year period, with at least five temporally independent 

samples. To be treated as a temporally independent sample, samples shall be at least one week 

apart, regardless whether the samples are collected at different locations within the segment. 

(a) Samples collected at the same location less than four days apart shall be considered 

as one sample, with the median value used to represent the sampling period. However, if any of the 

individual dissolved oxygen (DO) values are less than 1.5 mg/l or , for other parameters, individual 

values exceed acutely toxic levels as listed in Table 2, then the worst case value shall be used to 

represent the sampling period. The worst case value is the minimum value for DO, both the 

minimum and maximum for pH, or the maximum value for other parameters. However, when DO 

data are available from diel or depth profile studies, the lower tenth percentile value shall be used to 

represent worst case conditions for comparison against the minimum criteria. 

(b) Samples collected within 200 meters of each other will be considered the same station 

or location, unless there is a tributary, an outfall, or significant change in the hydrography of the 

water. 

(c) Samples collected from different stations within a water segment shall be assessed as 

separate samples even if collected at the same time. 

(d) In making the determination to list water segments, the Department shall consider 

ambient background conditions, including seasonal and other natural variations. 

Table 2. Acutely Toxic Levels for Parameters with Aquatic Life-Based 

Criteria 

Parameter Units Freshwater Value Marine Value 

Effective 9-4-07 Page 8 
DEP 2007          INDENTIFICATION OF IMPAIRED SURFACE WATERS     62‐303 

Aldrin ug/L 3 1.3 

Aluminum ug/L 750 N/A 

Arsenic ug/L 340 69 

Cadmium ug/L exp((1.0166*(lnH))-3.924) 40 

Chlordane ug/L 2.4 0.09 

Chlorine ug/L 19 13 

Chromium III ug/L exp((0.8190(lnH))+3.7256) N/A 

Chromium VI ug/L 16 1100 

Copper ug/L exp((0.9422*(lnH))-1.700) 5.8 

Cyanide ug/L 22 1 

DDT ug/L 1.1 0.13 

Dieldrin ug/L 0.24 0.71 

Endosulfan ug/L 0.22 0.034 

Endrin ug/L 0.086 0.037 

Heptachlor ug/L 0.52 0.053 

Lead ug/L exp((1.273(lnH))-1.460) 221 

Lindane ug/L 0.95 0.16 

Nickel ug/L exp((0.8460(lnH))+2.255) 75 

Parathion ug/L 0.065 N/A 

Pentachlorophenol ug/L exp(1.005(pH)-4.869) 13 

Selenium ug/L N/A 290 

Silver ug/L exp((1.72(lnH))-6.59) 2.2 

Toxaphene ug/L 0.73 0.21 

Zinc ug/L exp((0.8473(lnH))+0.884) 95 

 (5) For predominantly marine waters, the Department shall evaluate both the minimum 

allowable DO of 4.0 mg/l and the daily average DO criterion of 5.0 mg/l using Table 1. At least four 

temporally independent samples are required to calculate the daily average for any given day. For 

DO, temporally independent shall be defined as at least 4 hours apart. If there are sufficient data to 

determine daily averages for more than one day within a four-day period, the Department shall use 

the median value of the daily averages to represent the sampling period. 

(6) Notwithstanding the requirements of paragraph (4), water segments shall be included 

on the planning list if: 

(a) There are less than ten samples for the segment, but there are three or more 

temporally independent samples that do not meet an applicable water quality criterion, or 

(b) More than one sample does not meet an acute toxicity-based water quality criterion 

listed in Chapter 62-302.530, F.A.C., or a water quality criterion for a synthetic organic compound or 

synthetic pesticide in any three year period. 

(7) Values that exceed possible physical or chemical measurement constraints (pH 

greater than 14, for example) or that represent data transcription errors shall be excluded from the 

assessment. Outliers identified through statistical procedures shall be evaluated to determine 

whether they represent valid measures of water quality. If the Department determines that they are 

not valid, they shall be excluded from the assessment. However, the Department shall note for the 

record that the data were excluded and explain why they were excluded. 

(8) The Department shall consider all readily available water quality data collected and 

analyzed in accordance with Chapter 62-160, F.A.C. If requested, the sampling agency must 

Effective 9-4-07 Page 9 
DEP 2007          INDENTIFICATION OF IMPAIRED SURFACE WATERS     62‐303 

provide to the Department all of the data quality assessment elements listed in Table 2 of the 

Department’s Guidance Document “Data Quality Assessment Elements for Identification of Impaired 

Surface Waters” (DEP EAS 01-01, April 2001), which is incorporated by reference. 

(9) For the assessment of metals criteria, 

 (a) Surface water data for mercury shall be collected and analyzed using clean sampling 

and analytical techniques, and 

(b) The corresponding hardness value shall be required for freshwater metals criteria that 

are hardness dependent. If the ambient hardness value is less than 25 mg/L as CaCO3, then a 

hardness value of 25 will be used to calculate the criteria. If data are not used due to sampling or 

analytical techniques or because hardness data were not available, the Department shall note for 

the record that data were excluded and explain why they were excluded. 

(10) Surface water data with values below the applicable practical quantification limit (PQL) 

or method detection limit (MDL) shall be assessed in accordance with Rules 62-4.246(6)(b)-(d) and 

(8), F.A.C. 

(a) If sampling entities want to ensure that their data will be considered for evaluation, 

they should review the Department’s list of approved MDLs and PQLs developed pursuant to Rule 

62-4.246, F.A.C., and, if available, use approved analytical methods with MDLs below the applicable 

water quality criteria. If there are no approved methods with MDLs below a criterion, then the 

method with the lowest MDL should be used. Analytical results listed as below detection or below 

the MDL shall not be used for developing planning lists if the MDL was above the criteria and there 

were, at the time of sample collection, approved analytical methods with MDLs below the criteria on 

the Department’s list of approved MDLs and PQLs. 

(b) If appropriate analytical methods were used, then data with values below the 

applicable MDL will be deemed to meet the applicable water quality criterion and data with values 

between the MDL and PQL will be deemed to be equal to the MDL. 

(11) It should be noted that the data requirements of this rule constitute the minimum data 

set needed to assess a water segment for impairment. Agencies or groups designing monitoring 

networks are encouraged to consult with the Department to determine the sample design 

appropriate for their specific monitoring goals. 

Specific Authority 403.061, 403.067 FS. Law Implemented 403.062, 403.067 FS. History - New 6-

10-02, Amended 12-11-06. 

 62-303.330 Biological Assessment. 

(1) Biological data must meet the requirements of paragraphs (3) and (8) in section 62-

303.320, F.A.C. 

(2) Bioassessments used to assess streams and lakes under this rule shall include 

BioRecons, Stream Condition Indices (SCIs), and the benthic macroinvertebrate component of the 

Lake Condition Index (LCI), which only applies to clear lakes with a color less than 20 platinum 

cobalt units. Because these bioassessment procedures require specific training and expertise, 

persons conducting the bioassessments must comply with the quality assurance requirements of 

Chapter 62-160, F.A.C., attend at least eight hours of Department sanctioned field training, and 

pass a Department sanctioned field audit that verifies the sampler follows the applicable SOPs in 

Chapter 62-160, F.A.C., before their bioassessment data will be considered valid for use under this 

rule. 

Effective 9-4-07 Page 10 
DEP 2007          INDENTIFICATION OF IMPAIRED SURFACE WATERS     62‐303 

(3) Water segments with at least one failed bioassessment or one failure of the biological 

integrity standard, Rule 62-302.530(11), F.A.C., shall be included on the planning list for 

assessment of aquatic life use support. 

(a) In streams, the bioassessment shall be either an SCI or a BioRecon. Failure of a 

bioassessment for streams consists of a “poor” or “very poor” rating on the Stream Condition Index, 

or a “fail” rating on the BioRecon. 

(b) Failure for lakes consists of a “poor” or “very poor” rating on the Lake Condition Index. 

(4) Other information relevant to the biological integrity of the water segment, including 

toxicity tests and information about alterations in the type, nature, or function of a waterbody, shall 

also be considered when assessing aquatic life use support. 

Specific Authority 403.061, 403.067 FS. Law Implemented 403.062, 403.067 FS. History - New 6-

10-02, Amended 12-11-06. 

62-303.340 Toxicity. (Repealed) 

Specific Authority 403.061, 403.067 FS. Law Implemented 403.062, 403.067 FS. History - New 6-

10-02, Repealed 12-11-06. 

62-303.350 Interpretation of Narrative Nutrient Criteria. 

(1) Trophic state indices (TSIs) and annual mean chlorophyll a values shall be the primary 

means for assessing whether a water should be assessed further for nutrient impairment. Other 

information indicating an imbalance in flora or fauna due to nutrient enrichment, including, but not 

limited to, algal blooms, excessive macrophyte growth, decrease in the distribution (either in density 

or areal coverage) of seagrasses or other submerged aquatic vegetation, changes in algal species 

richness, and excessive diel oxygen swings, shall also be considered. 

(2) To be used to determine whether a waterbody should be assessed further for nutrient 

enrichment, 

(a) Data must meet the requirements of paragraphs (2)-(4), (7), and (8) in rule 62-

303.320, F.A.C. 

(b) At least one sample from each season shall be required in any given year to calculate 

a Trophic State Index (TSI) or an annual mean chlorophyll a value for that year (for purposes of this 

chapter, the four seasons shall be January 1 through March 31, April 1 through June 30, July 1 

through September 30, October 1 through December 31), 

(c) If there are multiple chlorophyll a or TSI values within a season, the average value for 

that season shall be calculated from the individual values and the four quarterly values shall be 

averaged to calculate the annual mean for that calendar year, 

(d) For data collected after the effective date of this rule, individual TSI values shall only 

be calculated when the nitrogen, phosphorus, and chlorophyll data were collected at the same time 

and location, 

(e) If there are insufficient data used to calculate a TSI or an annual mean chlorophyll a 

value in the planning period, but there are data from at least four consecutive seasons, the mean 

TSI or mean chlorophyll a value for the consecutive seasons shall be used to assess the waterbody, 

(f) There must be annual means from at least four years when evaluating the change in 

TSI over time pursuant to paragraph 62-303.352(3), F.A.C., and 

(g) To be assessed under this rule, chlorophyll a data collected after the effective date of 

this rule shall be corrected chlorophyll a, except for data used to establish historical chlorophyll a 

levels. Corrected chlorophyll a is the calculated concentration of chlorophyll a remaining after the 

Effective 9-4-07 Page 11 
DEP 2007          INDENTIFICATION OF IMPAIRED SURFACE WATERS     62‐303 

chlorophyll degradation product, phaeophytin a, has been subtracted from the uncorrected 

chlorophyll a measurement. 

(3) When comparing changes in chlorophyll a or TSI values to historical levels, historical 

levels shall be based on the lowest five-year average for the period of record. To calculate a fiveyear average, there must be annual means from at least three years of the five-year period. 

Specific Authority 403.061, 403.067 FS. Law Implemented 403.062, 403.067 FS. History - New 6-

10-02, Amended 12-11-06. 

62-303.351 Nutrients in Streams. 

A stream or stream segment shall be included on the planning list for nutrients if the following 

biological imbalances are observed: 

(1) Algal mats are present in sufficient quantities to pose a nuisance or hinder 

reproduction of a threatened or endangered species, or 

(2) Annual mean chlorophyll a concentrations are greater than 20 ug/l or if data indicate 

annual mean chlorophyll a values have increased by more than 50% over historical values for at 

least two consecutive years. 

Specific Authority 403.061, 403.067 FS. Law Implemented 403.062, 403.067 FS. History - New 6-

10-02, Repromulgated 1-2-07. 

62-303.352 Nutrients in Lakes. 

For the purposes of evaluating nutrient enrichment in lakes, TSIs shall be calculated based on the 

procedures outlined on pages 86 and 87 of the State’s 1996 305(b) report, which are incorporated 

by reference. Lakes or lake segments shall be included on the planning list for nutrients if: 

(1) For lakes with a mean color greater than 40 platinum cobalt units, the annual mean 

TSI for the lake exceeds 60, unless paleolimnological information indicates the lake was naturally 

greater than 60, or 

(2) For lakes with a mean color less than or equal to 40 platinum cobalt units, the annual 

mean TSI for the lake exceeds 40, unless paleolimnological information indicates the lake was 

naturally greater than 40, or 

(3) For any lake, data indicate that annual mean TSIs have increased over the 

assessment period, as indicated by a positive slope in the means plotted versus time, or the annual 

mean TSI has increased by more than 10 units over historical values. When evaluating the slope of 

mean TSIs over time, the Department shall require at least a 5 unit increase in TSI over the 

assessment period and use a Mann’s one-sided, upper-tail test for trend, as described in 

Nonparametric Statistical Methods by M. Hollander and D. Wolfe (1999 ed.), pages 376 and 724 

(which are incorporated by reference), with a 95% confidence level. 

Specific Authority 403.061, 403.067 FS. Law Implemented 403.062, 403.067 FS. History - New 6-

10-02, Amended 12-11-06. 

62-303.353 Nutrients in Estuaries and Open Coastal Waters. 

Estuaries, estuary segments, or open coastal waters shall be included on the planning list for 

nutrients if their annual mean chlorophyll a for any year is greater than 11 ug/l or if data indicate 

annual mean chlorophyll a values have increased by more than 50% over historical values for at 

least two consecutive years. 

Specific Authority 403.061, 403.067 FS. Law Implemented 403.062, 403.067 FS. History - New 6-

10-02, Amended 12-11-06. 

Effective 9-4-07 Page 12 
DEP 2007          INDENTIFICATION OF IMPAIRED SURFACE WATERS     62‐303 

62-303.360 Primary Contact and Recreation Use Support. 

 (1) A Class I, II, or III water shall be placed on the planning list for evaluating primary 

contact and recreation use support if: 

 (a) There is a sufficient number of samples from the water segment that do not meet the 

applicable water quality criteria for bacteriological quality based on the methodology described in 

Rule 62-303.320, F.A.C., with the exception that paragraph 62-303.320(4)(a), F.A.C., does not apply 

and samples collected on different days within any four day period will be assessed as daily 

samples, or 

 (b) The water segment includes a bathing area that was closed by a local health 

Department or county government for more than one week or more than once during a calendar 

year based on bacteriological data, or 

 (c) The water segment includes a bathing area for which a local health Department or 

county government has issued closures, advisories, or warnings totaling 21 days or more during a 

calendar year based on bacteriological data, or 

 (d) The water segment includes a bathing area that was closed or had advisories or 

warnings for more than 12 weeks during a calendar year based on previous bacteriological data or 

on derived relationships between bacteria levels and rainfall or flow, or 

 (e) The water segment includes a sampling location that has one or more monthly 

geometric mean values above the monthly geometric mean fecal coliform or enterococci criterion 

during the planning period. To calculate a monthly geometric mean, there shall be at least ten 

samples collected within that month, with at least one sample from each full week of the month. 

 (2) When evaluating a water segment for bacteriological quality under paragraph (1)(a), 

the criterion used for fecal coliforms shall be that the Most Probable Number (MPN) or Membrane 

Filter (MF) shall not exceed 400 counts per 100 ml. 

 (3) For data collected after August 1, 2000, the Florida Department of Health (DOH) 

database shall be the primary source of data used for determining bathing area closures. 

 (4) Advisories, warnings, and closures based on red tides, rip tides, sharks, hurricanes, or 

short-term releases of pollutants, such as sewage spills that have been repaired and medical 

wastes, shall not be included when assessing recreation use support. However, the Department 

shall note for the record that data were excluded and explain why they were excluded. 

Specific Authority 403.061, 403.067 FS. Law Implemented 403.062, 403.067 FS. History–New 6-10-

02, Amended 12-11-06, 9-4-07. 

62-303.370 Fish and Shellfish Consumption Use Support. 

A Class I, II, or III water shall be placed on the planning list for fish and shellfish consumption if: 

 (1) There is a sufficient number of samples from the water segment that do not meet the 

applicable Class II water quality criteria for bacteriological quality based on the methodology 

described in Rule 62-303.320, F.A.C., with the exception that paragraph 62-303.320(4)(a), F.A.C., 

does not apply and samples collected on different days within any four day period will be assessed 

as daily samples,or 

 (2) There is either a limited or no consumption fish consumption advisory, issued by the 

DOH, or other authorized governmental entity, in effect for the water segment, or 

 (3) For Class II waters, the water segment includes an area that is classified by the 

Department of Agriculture and Consumer Services’ Shellfish Environmental Assessment Section 

(SEAS) in one of the following shellfish harvesting classifications: 

Effective 9-4-07 Page 13 
DEP 2007          INDENTIFICATION OF IMPAIRED SURFACE WATERS     62‐303 

 (a) Restricted or conditionally restricted, 

 (b) Conditionally approved, excluding any areas for which SEAS identified only wildlife as 

the potential source of bacteriological contamination for the shellfish harvesting area, or 

 (c) Prohibited, unless the prohibited classification is precautionary and not based on water 

quality data. 

 (4) For Class II waters, the water segment includes a sampling location that has a median 

fecal coliform MPN value that exceeds 14 counts per 100 ml for the planning period. To calculate a 

median value for a sampling location, there shall be at least 10 samples collected during the 

planning period. 

 (5) When evaluating a water segment for bacteriological quality under subsection (1), the 

criterion in subsection 62-302.530(6), F.A.C., used for fecal coliform shall be that the MPN shall not 

exceed 43 counts per 100 ml. 

Specific Authority 403.061, 403.067 FS. Law Implemented 403.062, 403.067 FS. History–New 6-10-

02, Amended 12-11-06, 9-4-07. 

62-303.380 Drinking Water Use Support and Protection of Human Health. 

 (1) A Class I water shall be placed on the planning list for drinking water use support if: 

 (a) There is a sufficient number of samples from the water segment that do not meet the 

applicable Class I water quality criteria based on the methodology described in Rule 62-303.320, 

F.A.C., with the exception that paragraph 62-303.320(4)(a), F.A.C., does not apply and samples 

collected on different days within any four day period will be assessed as daily samples, or 

 (b) A public water system demonstrates to the Department that either: 

 1. Treatment costs to meet applicable drinking water criteria have increased by at least 

25% to treat contaminants that exceed Class I criteria or to treat blue-green algae or other nuisance 

algae in the source water, or 

 2. The system has changed to an alternative supply because of additional costs that 

would be required to treat their surface water source. 

 (c) The water segment includes a sampling location that has one or more monthly 

geometric mean values above the monthly geometric mean fecal coliform criterion during the 

planning period. To calculate a monthly geometric mean value for a sampling location, there shall be 

at least five samples collected within that month, with at least one sample from each full week of the 

month. 

 (2) When determining increased treatment costs described in paragraph (b), costs due 

solely to new, more stringent drinking water requirements, inflation, or increases in costs of 

materials shall not be included. 

 (3) A water shall be placed on the planning list for assessment of the threat to human 

health if: 

 (a) For human health-based criteria expressed as maximums, the water segment does 

not meet the applicable criteria based on the methodology described in Rule 62-303.320, F.A.C., or 

 (b) For human health-based criteria expressed as annual averages, the annual average 

concentration for any year of the assessment period exceeds the criteria. To be used to determine 

whether a water should be assessed further for human-health impacts, data must meet the 

requirements of subsections (2), (3), (6), and (7) in Rule 62-303.320, F.A.C. 

 (4) When evaluating a water segment for bacteriological quality under paragraph (1)(a), 

the criterion used for fecal coliforms shall be that the MPN or MF shall not exceed 400 counts per 

100 ml. 

Effective 9-4-07 Page 14 
DEP 2007          INDENTIFICATION OF IMPAIRED SURFACE WATERS     62‐303 

Specific Authority 403.061, 403.067 FS. Law Implemented 403.062, 403.067 FS. History–New 6-10-

02, Amended 12-11-06, 9-4-07. 

PART III 

THE VERIFIED LIST 

62-303.400 Methodology to Develop the Verified List. 

(1) Waters shall be verified as being impaired if they meet the requirements for the 

planning list in Part II and the additional requirements of sections 62-303.420-.480, F.A.C. A water 

body that fails to meet the minimum criteria for surface waters established in Rule 62-302.500, 

F.A.C.; any of its designated uses, as described in this part; or applicable water quality criteria, as 

described in this part, shall be determined to be impaired. 

(2) Additional data and information collected after the development of the planning list will 

be considered when assessing waters on the planning list, provided it meets the requirements of 

this chapter. In cases where additional data are needed for waters on the planning list to meet the 

data sufficiency requirements for the verified list, it is the Department’s goal to collect this additional 

data as part of its watershed management approach, with the data collected during either the same 

cycle that the water is initially listed on the planning list (within 1 year) or during the subsequent 

cycle (six years). 

(3) Unless information presented to the Department demonstrates otherwise, data more 

than 7.5 years old at the time the water segment is proposed for listing on the verified list are not 

representative of current conditions and shall not be used except to evaluate historical trends in 

chlorophyll a or TSIs. Any determinations by the Department to use data older than 7.5 years shall 

be documented, and the documentation shall include the basis for the decision. 

Specific Authority 403.061, 403.067 FS. Law Implemented 403.062, 403.067 FS. History - New 6-

10-02, Amended 12-11-06. 

62-303.410 Determination of Aquatic Life Use Support. 

Failure to meet any of the metrics used to determine aquatic life use support listed in sections 62-

303.420-.450 shall constitute verification that there is an impairment of the designated use for 

propagation and maintenance of a healthy, well-balanced population of fish and wildlife. 

Specific Authority 403.061, 403.067 FS. Law Implemented 403.062, 403.067 FS. History - New 6-

10-02, Repromulgated 1-2-07. 

62-303.420 Aquatic Life-Based Water Quality Criteria Assessment. 

(1) The Department shall reexamine the data used in rule 62-303.320, F.A.C., to 

determine whether water quality criteria are met. 

(a) If values exceeding the criteria are not due to pollutant discharges or reflect natural 

background conditions, including seasonal or other natural variations, the water shall not be listed 

on the verified list. In such cases, the Department shall note for the record why the water was not 

listed and provide the basis for its determination that the exceedances were not due to pollutant 

discharges. 

(b) If the Department has information suggesting that the values not meeting the criterion 

are due to natural background conditions, including information about the in-stream concentrations 

of TN, TP, and BOD relative to comparable reference waters for waterbodies with values below the 

DO criterion, it is the Department’s intent to support that conclusion through the use of 

Effective 9-4-07 Page 15 
DEP 2007          INDENTIFICATION OF IMPAIRED SURFACE WATERS     62‐303 

bioassessment procedures referenced in section 62-303.330, F.A.C. The water body or segment 

shall not be included on the verified list for the parameter of concern if two or more independent 

bioassessments are conducted and no failures are reported. To be treated as independent 

bioassessments, they must be conducted at least two months apart, within the assessed segment 

downstream of where the samples were measured, and after the samples were measured. 

(2) If the water was listed on the planning list and there were insufficient data from the last 

five years preceding the planning list assessment to meet the data distribution requirements of 

section 303.320(4), F.A.C., and to meet a minimum sample size for verification of twenty samples, 

additional data will be collected as needed to provide a minimum sample size of twenty. Once these 

additional data are collected, the Department shall re-evaluate the data using the approach outlined 

in rule 62-303.320(1), F.A.C., but using Table 3, and place waters on the verified list when 10% or 

more of the samples do not meet the applicable criteria, with a minimum of a 90% confidence level 

using a binomial distribution. The Department shall limit the analysis to data collected during the 

five years preceding the planning list assessment and the additional data collected pursuant to this 

paragraph. For sample sizes greater than 500, the Department shall calculate the number of 

samples not meeting the criterion that are needed for the given sample size using the binomial 

distribution. 

Effective 9-4-07 Page 16 
DEP 2007          INDENTIFICATION OF IMPAIRED SURFACE WATERS     62‐303 

Table 3: Verified List 

Minimum number of samples not meeting an applicable water quality criterion 

needed to put a water on the Verified list with at least 90% confidence. 

Sample sizes Sample sizes 

From To 

Are listed if 

they have at 

least this #of 

samples that do 

not meet a 

criterion From To 

Are listed if 

they have at 

least this # of 

samples that 

do not meet a 

criterion 

20 25 5 254 262 33 

26 32 6 263 270 34 

33 40 7 271 279 35 

41 47 8 280 288 36 

48 55 9 289 297 37 

56 63 10 298 306 38 

64 71 11 307 315 39 

72 79 12 316 324 40 

80 88 13 325 333 41 

89 96 14 334 343 42 

97 104 15 344 352 43 

105 113 16 353 361 44 

114 121 17 362 370 45 

122 130 18 371 379 46 

131 138 19 380 388 47 

139 147 20 389 397 48 

148 156 21 398 406 49 

157 164 22 407 415 50 

165 173 23 416 424 51 

174 182 24 425 434 52 

183 191 25 435 443 53 

192 199 26 444 452 54 

200 208 27 453 461 55 

209 217 28 462 470 56 

218 226 29 471 479 57 

227 235 30 480 489 58 

236 244 31 490 498 59 

245 253 32 499 500 60 

Effective 9-4-07 Page 17 
DEP 2007          INDENTIFICATION OF IMPAIRED SURFACE WATERS     62‐303 

 (3) If the water was placed on the planning list based on worst case values used to 

represent multiple samples taken during a four day period, the Department shall evaluate whether 

the worst case value should be excluded from the analysis pursuant to subsections (4) and (5). If 

the worst case value should not be used, the Department shall then re-evaluate the data following 

the methodology in rule 62-303.420(2), F.A.C., using the more representative worst case value or, if 

all valid values are below acutely toxic levels, the median value. 

(4) If the water was listed on the planning list based on samples that do not meet water 

quality criteria for metals, the metals data shall be excluded if it is determined that the quality 

assurance requirements of rule 62-303.320(8), F.A.C., were not met or that the sample was not 

collected and analyzed using clean techniques, if the use of clean techniques is appropriate. The 

Department shall re-evaluate the remaining valid data using the methodology in rule 62-303.420(2), 

F.A.C., excluding any data that cannot be validated. 

(5) Values that exceed possible physical or chemical measurement constraints (pH 

greater than 14, for example) or that represent data transcription errors, outliers the Department 

determines are not valid measures of water quality, water quality criteria exceedances due solely to 

violations of specific effluent limitations contained in state permits authorizing discharges to surface 

waters, water quality criteria exceedances within permitted mixing zones for those parameters for 

which the mixing zones are in effect, and water quality data collected following contaminant spills, 

discharges due to upsets or bypasses from permitted facilities, or rainfall in excess of the 25-year, 

24-hour storm, shall be excluded from the assessment carried out under this rule. However, the 

Department shall note for the record that the data were excluded and explain why they were 

excluded. 

(6) Once the additional data review is completed pursuant to paragraphs (1) through (5), 

the Department shall re-evaluate the data and shall include waters on the verified list that meet the 

criteria in rules 62-303.420(2) or 62-303.320(6)(b), F.A.C. 

(7) Notwithstanding the requirements of paragraph (2), water segments shall also be 

included on the verified list if, based on representative data collected and analyzed in accordance 

with Chapter 62-160, F.A.C.: 

(a) There are less than twenty samples, 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, or 

(b) Scientifically credible and compelling information regarding the magnitude, frequency, 

or duration of samples that do not meet an applicable water quality criterion provides overwhelming 

evidence of impairment. Any determinations to list waters based on this provision shall be 

documented, and the documentation shall include the basis for the decision. 

(c) For any water chemistry data used to list waters under this paragraph, the Department 

shall include in the administrative record all of the applicable data quality assessment elements 

listed in Table 2 of the Department’s Guidance Document “Data Quality Assessment Elements for 

Identification of Impaired Surface Waters” (DEP EAS 01-01, April 2001). 

Specific Authority 403.061, 403.067 FS. Law Implemented 403.021(11), 403.062, 403.067 FS. 

History - New 6-10-02, Amended 12-11-06. 

62-303.430 Biological Impairment. 

(1) All bioassessments used to list a water on the verified list shall be conducted in 

accordance with Chapter 62-160, F.A.C., including Department-approved Standard Operating 

Procedures. To be used for placing waters on the verified list, any bioassessments conducted 

Effective 9-4-07 Page 18 
DEP 2007          INDENTIFICATION OF IMPAIRED SURFACE WATERS     62‐303 

before the adoption of applicable SOPs for such bioassessments as part of Chapter 62-160, F.A.C., 

shall substantially comply with the subsequent SOPs. 

(2) If the water was listed on the planning list based on bioassessment results, the water 

shall be determined to be biologically impaired if there were two or more failed bioassessments 

within the five years preceding the planning list assessment. If there were less than two failed 

bioassessments during the last five years preceding the planning list assessment, the Department 

will conduct an additional bioassessment. If the previous failed bioassessment was a BioRecon, 

then an SCI will be conducted. Failure of this additional bioassessment shall constitute verification 

that the water is biologically impaired. 

(3) If the water was listed on the planning list based on other information specified in rule 

62-303.330(4), F.A.C., indicating biological impairment, the Department will conduct a 

bioassessment in the water segment, conducted in accordance with the methodology in rule 62-

303.330, F.A.C., to verify whether the water is impaired. For streams, the bioassessment shall be 

an SCI. Failure of this bioassessment shall constitute verification that the water is biologically 

impaired. 

(4) Following verification that a waterbody is biologically impaired, a water shall be 

included on the verified list for biological impairment if: 

(a) There are water quality data reasonably demonstrating the particular pollutant(s) 

causing the impairment and the concentration of the pollutant(s); and 

(b) One of the following demonstrations is made: 

1. If there is a numeric criterion for the specified pollutant(s) in Chapter 62-302, F.A.C., 

but the criterion is met, an identification of the specific factors that reasonably demonstrate why the 

numeric criterion is not adequate to protect water quality and how the specific pollutant is causing 

the impairment, or 

2. If there is not a numeric criterion for the specified pollutant(s) in Chapter 62-302, 

F.A.C., an identification of the specific factors that reasonably demonstrate how the particular 

pollutant(s) are associated with the observed biological effect. 

Specific Authority 403.061, 403.067 FS. Law Implemented 403.062, 403.067 FS. History - New 6-

10-02, Amended 12-11-06. 

62-303.440 Toxicity. (Repealed) 

Specific Authority 403.061, 403.067 FS. Law Implemented 403.062, 403.067 FS. History - New 6-

10-02, Repealed 12-11-06. 

62-303.450 Interpretation of Narrative Nutrient Criteria. 

(1) A water shall be placed on the verified list for impairment due to nutrients if there are 

sufficient data from the last five years preceding the planning list assessment, combined with 

historical data (if needed to establish historical chlorophyll a levels or historical TSIs), to meet the 

data sufficiency requirements of rule 62-303.350(2), F.A.C. If there are insufficient data, additional 

data shall be collected as needed to meet the requirements. Once these additional data are 

collected, the Department shall determine if there is sufficient information to develop a site-specific 

threshold that better reflects conditions beyond which an imbalance in flora or fauna occurs in the 

water segment. If there is sufficient information, the Department shall re-evaluate the data using the 

site-specific thresholds. If there is insufficient information, the Department shall re-evaluate the data 

using the thresholds provided in rule 62-303.351-.353, F.A.C., for streams, lakes, and estuaries, 

respectively. In any case, the Department shall limit its analysis to the use of data collected during 

Effective 9-4-07 Page 19 
DEP 2007          INDENTIFICATION OF IMPAIRED SURFACE WATERS     62‐303 

the five years preceding the planning list assessment and the additional data collected in the second 

phase. If alternative thresholds are used for the analysis, the Department shall provide the 

thresholds for the record and document how the alternative threshold better represents conditions 

beyond which an imbalance in flora or fauna is expected to occur. 

(2) If the water was listed on the planning list for nutrient enrichment based on other 

information indicating an imbalance in flora or fauna, as provided in Rule 62-303.350(1), F.A.C., the 

Department shall verify the imbalance before placing the water on the verified list for impairment due 

to nutrients and shall provide documentation supporting the imbalance in flora or fauna. 

(3) The thresholds for impairment due to nutrients used under this section are not required 

to be used during development of wasteload allocations or TMDLs. 

Specific Authority 403.061, 403.067 FS. Law Implemented 403.062, 403.067 FS. History - New 6-

10-02, Amended 12-11-06. 

62-303.460 Primary Contact and Recreation Use Support. 

 (1) The Department shall review the data used by the DOH as the basis for bathing area 

closures, advisories or warnings and verify that the values exceeded the applicable DOH thresholds 

and the data meet the requirements of Chapter 62-160, F.A.C. If the segment is listed on the 

planning list based on bathing area closures, advisories, or warnings issued by a local health 

department or county government, closures, advisories, or warnings based on red tides, rip tides, 

sewer line breaks, sharks, medical wastes, hurricanes, or other factors not related to chronic 

discharges of pollutants shall not be included when verifying primary contact and recreation use 

support. The Department shall then re-evaluate the remaining data using the methodology in 

paragraph 62-303.360(1)(c), F.A.C. Water segments that meet the criteria in paragraph 62-

303.360(1)(c), F.A.C., shall be included on the verified list. 

 (2) If the water segment was listed on the planning list due to samples that do not meet 

water quality criteria for bacteriological quality, the Department shall, to the extent practical, evaluate 

the source of bacteriological contamination and shall verify that the impairment is due to chronic 

discharges of human-induced bacteriological pollutants before listing the water segment on the 

verified list. The Department shall take into account the proximity of municipal stormwater outfalls, 

septic tanks, and domestic wastewater facilities when evaluating potential sources of bacteriological 

pollutants. For water segments that contain municipal stormwater outfalls, the impairment 

documented for the segment shall be presumed to be due, at least in part, to chronic discharges of 

bacteriological pollutants. The Department shall then re-evaluate the data using the methodology in 

subsection 62-303.320(1), F.A.C., excluding any values that are elevated solely due to wildlife, or for 

enterococci in coastal recreational waters, adjusting the values based on the human health-related 

risk factors for wildlife-based enterococci upon meeting the relevant requirements of 40 CFR 

131.41(c)(2). 

 (3) Water segments shall be included on the verified list if: 

 (a) The number of samples that do not meet the applicable single-sample bacteriological 

water quality criteria meet the requirements in subsection 62-303.420(6), F.A.C., with the exception 

that paragraph 62-303.320(4)(a), F.A.C., does not apply and samples collected on different days 

within any four day period will be assessed as daily samples, or 

 (b) There are one or more exceedances of a bacteriological water quality criterion 

expressed as a monthly geometric mean during the verified period. To assess the monthly data for a 

sampling location, there shall be at least ten samples collected within that month, with at least one 

sample from each full week of the month. 

Effective 9-4-07 Page 20 
DEP 2007          INDENTIFICATION OF IMPAIRED SURFACE WATERS     62‐303 

(4) When evaluating a water segment for bacteriological quality under paragraph 62-303.460(3)(a), 

F.A.C., the criterion used for fecal coliforms shall be that the Most Probable Number (MPN) or 

Membrane Filter (MF) shall not exceed 400 counts per 100 ml. 

 (5) When assessing waters pursuant to paragraphs 62-303.460(3)(a) and (b), F.A.C., the 

Department shall evaluate whether the samples are representative and are not biased toward 

collecting samples at times either under the influence of wet weather conditions or absent the 

influence of wet weather conditions. Representative sampling generally reflects a consistent number 

of samples evenly spaced over regular intervals. Any determinations to exclude waters based on 

this provision shall be documented, and the documentation shall include the basis for the decision. 

Specific Authority 403.061, 403.067 FS. Law Implemented 403.062, 403.067 FS. History–New 6-10-

02, Amended 12-11-06, 9-4-07. 

62-303.470 Fish and Shellfish Consumption Use Support. 

 (1) In order to be used under this part, the Department shall review the data used by the 

DOH as the basis for fish consumption advisories and determine whether it meets the following 

requirements: 

 (a) The advisory is based on the statistical evaluation of fish tissue data from at least 

twelve fish collected from the specific water segment or water body to be listed, 

 (b) The data are collected in accordance with DEP SOP FS6000 (General Biological 

Tissue Sampling) and FS 6200 (Finfish Tissue Sampling), which are incorporated by reference, the 

sampling entity has established Data Quality Objectives (DQOs) for the sampling, and the data meet 

the DQOs, and 

 (c) There are sufficient data or other information from within the last 7.5 years that would 

support the continuation of the advisory. The Department shall document any decision to list waters 

with advisories older than 7.5 years, including the data supporting the continuation of the advisory or 

information demonstrating that older data are representative of current conditions. 

 (2) Waters with advisories determined to meet the requirements of this section or waters 

where scientifically credible and compelling information meeting the requirements of Chapter 62-

160, F.A.C., indicates the applicable human health-based water quality criteria are not met shall be 

listed on the verified list. Any determinations to list waters based on this provision shall be 

documented, and the documentation shall include the basis for the decision. 

 (3) Class II waters shall be included on the verified list for coliform impairment if, following 

review of the available data as described in subsection 62-303.460(2), F.A.C. 

 (a) The number of samples above 43 counts per 100 ml meet the requirement in 

subsection 62-303.420(6), F.A.C., with the exception that paragraph 62-303.320(4)(a), F.A.C., does 

not apply and samples collected on different days within any four day period will be assessed as 

daily samples,or 

 (b) The water segment includes a sampling location that has a median fecal coliform MPN 

value that exceeds 14 counts per 100 ml for the verified period. To calculate a median value for a 

sampling location, there shall be at least 20 samples collected during the verified period. 

 (4) Waters that qualify for placement on the planning list based on shellfish harvesting 

classification information shall be verified as impaired for fecal coliforms. 

Specific Authority 403.061, 403.067 FS. Law Implemented 403.062, 403.067 FS. History–New 6-10-

02, Amended 12-11-06, 9-4-07. 

Effective 9-4-07 Page 21 
DEP 2007          INDENTIFICATION OF IMPAIRED SURFACE WATERS     62‐303 

62-303.480 Drinking Water Use Support and Protection of Human Health. 

If the water segment was listed on the planning list due to exceedances of a human health-based 

water quality criterion and there were insufficient data from the last five years preceding the planning 

list assessment to meet the data sufficiency requirements of subsection 62-303.320(4), F.A.C., 

additional data will be collected as needed to meet the requirements. Once these additional data are 

collected, the Department shall re-evaluate the data using the methodology in subsection 62-

303.380(2), F.A.C., and limit the analysis to data collected during the five years preceding the 

planning list assessment, the additional data collected pursuant to this paragraph (not to include 

data older than 7.5 years), and data older than 7.5 years if it is demonstrated to be representative of 

current conditions. Any determinations to use older data shall be documented by the Department, 

and the documentation shall provide the basis for the decision that the data are representative of 

current conditions. For this analysis, the Department shall exclude any data meeting the 

requirements of subsection 62-303.420(5), F.A.C. The following water segments shall be listed on 

the verified list: 

 (1) For human health-based criteria expressed as maximums, water segments that meet 

the requirements in subsection 62-303.420(7), F.A.C., or 

 (2) For human health-based criteria expressed as annual averages, water segments that 

have an annual average that exceeds the applicable criterion. 

 (3) For bacteriological water quality criteria, water segments shall be included on the 

verified list if, following review of the available data as described in subsections 62-303.460(2) and 

(5), F.A.C.: 

 (a) The number of samples that do not meet the applicable single-sample bacteriological 

water quality criteria meet the requirements in subsection 62-303.420(6), F.A.C., with the exception 

that paragraph 62-303.320(4)(a), F.A.C., does not apply and samples collected on different days 

within any four day period will be assessed as daily samples, or 

 (b) There are one or more exceedances of a bacteriological water quality criterion 

expressed as a monthly geometric mean during the verified period. To assess the monthly data for a 

sampling location there shall be at least five samples collected within that month, with at least one 

sample from each full week of the month. 

Specific Authority 403.061, 403.067 FS. Law Implemented 403.062, 403.067 FS. History–New 6-10-

02, Amended 12-11-06, 9-4-07. 

62-303.500 Prioritization. 

(1) When establishing the TMDL development schedule for water segments on the 

verified list of impaired waters, the Department shall prioritize impaired water segments according to 

the severity of the impairment and the designated uses of the segment, taking into account the most 

serious water quality problems; most valuable and threatened resources; and risk to human health 

and aquatic life. Impaired waters shall be prioritized as high, medium, or low priority. 

(2) The following waters shall be designated high priority: 

(a) Water segments where the impairment poses a threat to potable water supplies or to 

human health. 

(b) Water segments where the impairment is due to a pollutant regulated by the CWA and 

the pollutant has contributed to the decline or extirpation of a federally listed threatened or 

endangered species, as indicated in the Federal Register listing the species. 

(3) The following waters shall be designated low priority: 

Effective 9-4-07 Page 22 
DEP 2007          INDENTIFICATION OF IMPAIRED SURFACE WATERS     62‐303 

(a) water segments that are listed before 2010 due to fish consumption advisories for 

mercury (due to the current insufficient understanding of mercury cycling in the environment). 

(b) Man-made canals, urban drainage ditches, and other artificial water segments that are 

listed only due to exceedances of the dissolved oxygen criteria. 

(c) Water segments that were not on a planning list of impaired waters, but which were 

identified as impaired during the second phase of the watershed management approach and were 

included in the verified list, unless the segment meets the criteria in paragraph (2) for high priority. 

(4) All segments not designated high or low priority shall be medium priority and shall be 

prioritized based on the following factors: 

(a) The presence of Outstanding Florida Waters. 

(b) The presence of water segments that fail to meet more than one designated use. 

(c) The presence of water segments with greater than twenty-five percent of the samples 

not meeting an applicable water quality criterion or alternative threshold with a minimum of a 90 

percent confidence level. 

(d) The presence of water segments that exceed more than one applicable water quality 

criteria. 

(e) Administrative needs of the TMDL program, including meeting a TMDL development 

schedule agreed to with EPA, basin priorities related to following the Department’s watershed 

management approach, and the number of administratively continued permits in the basin. 

Specific Authority 403.061, 403.067 FS. Law Implemented 403.062, 403.067 FS. History - New 6-

10-02, Amended 12-11-06. 

62-303.600 Evaluation of Pollution Control Mechanisms. 

(1) Upon determining that a water body is impaired, the Department shall evaluate 

whether existing or proposed technology-based effluent limitations and other pollution control 

programs under local, state, or federal authority are sufficient to result in the attainment of applicable 

water quality standards. 

(2) If, as a result of the factors set forth in (1), the water segment is expected to attain 

water quality standards in the future and is expected to make reasonable progress towards 

attainment of water quality standards by the time the next 303(d) list is scheduled to be submitted to 

EPA, the segment shall not be listed on the verified list. The Department shall document the basis 

for its decision, noting any proposed pollution control mechanisms and expected improvements in 

water quality that provide reasonable assurance that the water segment will attain applicable water 

quality standards. 

Specific Authority 403.061, 403.067 FS. Law Implemented 403.062, 403.067 FS. History - New 6-

10-02, Repromulgated 1-2-07. 

62-303.700 Listing Cycle. 

The Department shall, to the extent practical, develop basin-specific verified lists of impaired waters 

as part of its watershed management approach, which rotates through the State’s surface water 

basins on a five year cycle. At the end of the first phase of the cycle, which is designed to develop a 

preliminary assessment of the basin, the Department shall update the planning list for the basin and 

shall include the planning list in the status report for the basin, which will be noticed to interested 

parties in the basin. If the specific pollutant causing the impairment in a particular water segment is 

not known at the time the planning list is prepared, the list shall provide the basis for including the 

water segment on the planning list. In these cases, the pollutant and concentration causing the 

Effective 9-4-07 Page 23 
DEP 2007          INDENTIFICATION OF IMPAIRED SURFACE WATERS     62‐303 

impairment shall be identified before the water segment is included on the verified list to be adopted 

by Secretarial Order. During the second phase of the cycle, which is designed to collect additional 

data on waters in the basin, interested parties shall be provided the opportunity to work with the 

Department to collect additional water quality data. Alternatively, interested parties may develop 

proposed water pollution control mechanisms that may affect the final verified list adopted by the 

Secretary at the end of the second phase. To ensure that data or information will be considered in 

the preliminary basin assessment, it must be submitted to the Department or entered into 

FLASTORET or, if applicable, the DOH database no later than September 30 during the year of the 

assessment. 

Specific Authority 403.061, 403.067 FS. Law Implemented 403.062, 403.067 FS. History - New 6-

10-02, Amended 12-11-06. 

62-303.710 Format of Verified List and Verified List Approval. 

(1) The Department shall follow the methodology established in this chapter to develop 

basin-specific verified lists of impaired water segments. The verified list shall specify the pollutant or 

pollutants causing the impairment and the concentration of the pollutant(s) causing the impairment. 

If the water segment is listed based on numeric water quality criteria, then the verified list shall 

provide the applicable criteria. However, if the listing is based on narrative or biological criteria, or 

impairment of other designated uses, and the water quality criteria are met, the list shall specify the 

concentration of the pollutant relative to the water quality criteria and explain why the numerical 

criterion is not adequate. 

(2) Segments impaired for pollutants that are no longer legally allowed to be used or 

discharged shall not be placed on the verified list because the TMDL will be zero for the pollutant. 

(3) For waters impaired for dissolved oxygen, the Department shall identify the pollutants 

causing or contributing to the impairment and list both the pollutant and dissolved oxygen on the 

verified list. 

(4) For waters impaired by nutrients, the Department shall identify whether nitrogen or 

phosphorus, or both, are the limiting nutrients for the verified period, and specify the limiting 

nutrient(s) in the verified list. 

(5) The verified list shall also include the priority and the schedule for TMDL development 

established for the water segment, as required by federal regulations. 

(6) The verified list shall also note any waters that are being removed from the current 

planning list and any previous verified list for the basin. 

(7) The verified basin-specific 303(d) list shall be approved by order of the Secretary. 

Specific Authority 403.061, 403.067 FS. Law Implemented 403.062, 403.067 FS. History - New 6-

10-02, Amended 12-11-06. 

PART IV 

MISCELLANEOUS PROVISIONS 

62-303.720 Delisting Procedure. 

 (1) Waters on planning lists developed under this chapter that are verified to not be 

impaired during development of the verified list shall be removed from the State’s planning list. Once 

a water segment is verified to not be impaired pursuant to Part III of this chapter, the data used to 

place the water on the planning list shall not be the sole basis for listing that water segment on 

future planning lists. 

Effective 9-4-07 Page 24 
DEP 2007          INDENTIFICATION OF IMPAIRED SURFACE WATERS     62‐303 

 (2) Water segments shall be removed from the State’s verified list only after completion of 

a TMDL for all pollutants causing impairment of the segment or upon demonstration that the water 

meets the water quality standard that was previously established as not being met. 

 (a) For waters listed due to failure to meet aquatic life use support based on water quality 

criteria or due to threats to human health based on single sample water quality criteria, the water 

shall be delisted when: 

 1. The number of samples that do not meet an applicable water quality criterion due to 

pollutant discharges is less than or equal to the number listed in Table 4 for the given sample size, 

with a minimum sample size of 30. Waters shall be delisted when 10% or less of the samples do not 

meet the applicable criterion with a minimum of a 90% confidence level using a binomial distribution, 

or 

 2. Following implementation of pollution control activities that are expected to be 

sufficient to result in attainment of applicable water quality standards, evaluation of new data 

indicates the water no longer meets the criteria for listing established in Rule 62-303.420, F.A.C., or 

 3. Following demonstration that the water was inappropriately listed due to flaws in the 

original analysis, evaluation of available data indicates the water does not meet the criteria for listing 

established in Rule 62-303.420, F.A.C. New data evaluated under subparagraph 62-

303.720(2)(a)1., F.A.C., must meet the following requirements: 

 a. They must include samples collected during similar conditions (same seasons and 

general flow conditions) that the data previously used to determine impairment were collected, with 

no more than 50% of the samples collected in any one quarter, 

 b. The sample size must be a minimum of 30 samples, and 

 c. The data must meet the requirements of subsections 62-303.320(4), (6) and (7), 

F.A.C. 

 (b) For waters listed due to failure to meet aquatic life use support based on biological 

data, the water shall be delisted when the segment passes two independent follow-up 

bioassessments and there have been no failed bioassessments for at least one year. The follow-up 

tests must meet the following requirements: 

 1. For streams, the new data may be two BioRecons or any combination of BioRecons 

and SCIs. 

 2. The bioassessments must be conducted during similar conditions (same seasons and 

general flow conditions) under which the previous bioassessments used to determine impairment 

were collected. 

 3. The data must meet the requirements of subsections 62-303.330(1) and (2), F.A.C. 

 (c) For waters listed due to fish consumption advisories, the water shall be delisted 

following the lifting of the advisory or when data complying with paragraphs 62-303.470(1)(a) and 

(b), F.A.C., demonstrate that the continuation of the advisory is no longer appropriate. 

 (d) For waters listed due to their shellfish bed management classification, the water shall 

be delisted upon reclassification of the shellfish harvesting area to approved, or for conditionally 

approved areas, when the only source identified by SEAS for the harvesting area is wildlife. 

 (e) For waters listed due to bathing area closure or advisory data, the water shall be 

delisted if the bathing area does not meet the listing thresholds in subsection 62-303.360(1), F.A.C., 

for five consecutive years. 

 (f) For waters listed based on impacts to potable water supplies, the water shall be 

delisted when applicable water quality criteria are met as defined in paragraph 62-303.380(1)(a), 

F.A.C., and when the causes resulting in higher treatment costs have been ameliorated. 

Effective 9-4-07 Page 25 
DEP 2007          INDENTIFICATION OF IMPAIRED SURFACE WATERS     62‐303 

 (g) For waters listed pursuant to paragraph 62-303.460(3)(b), 62-303.470(3)(b), or 62-

303.480(3)(b), F.A.C., the water shall be delisted when: 

 1. The criteria applicable to those sections are met for three consecutive years and there 

are sufficient new data available to calculate monthly values for at least the same seasons in which 

the exceedances occurred, or 

 2. Following a demonstration that the water was inappropriately listed due to flaws in the 

original analysis, including the use of a non-representative sample set. 

 (h) For waters listed pursuant to paragraph 62-303.460(3)(a), 62-303.470(3)(a), or 62-

303.480 (3)(a), F.A.C., the water shall be delisted upon meeting the delisting provisions in 

paragraph 62-303.720(2)(a), F.A.C. 

 (i) For waters listed based on a human health-based annual average criterion, the water 

shall be delisted when the annual average concentration is less than the criterion for three 

consecutive years. 

 (j) For waters listed based on nutrient impairment, the water shall be delisted if it does not 

meet the listing thresholds in Rule 62-303.450, F.A.C., for three consecutive years. 

 (k) For any listed water, the water shall be delisted if, following a change in approved 

analytical procedures, criteria, or water quality standards, evaluation of available data indicates the 

water no longer meets the applicable criteria for listing. 

 (l) For waters listed based on paragraph 62-303.420(7)(b) or subsection 62-303.470(3), 

F.A.C., the water shall be delisted if the Department determines the water is no longer impaired, 

based on scientifically credible and compelling information comparable in quantity and quality to the 

information used to make the initial listing decision. Any determinations to delist waters based on 

this provision shall be documented, and the documentation shall include the basis for the decision. 

Table 4. 

Delisting 

Maximum number of samples that do not meet an applicable water quality criterion 

allowable to DELIST with at least 90% confidence. 

Sample Sizes Maximum 

# of 

Samples 

not 

meeting a 

criterion 

allowable 

for 

delisting 

Sample sizes Maximum 

# of 

Samples 

not 

meeting a 

criterion 

allowable 

for 

delisting 

From To From To 

30 37 0 279 289 21 

38 51 1 290 300 22 

52 64 2 301 311 23 

65 77 3 312 323 24 

78 90 4 324 334 25 

91 103 5 335 345 26 

Effective 9-4-07 Page 26 
DEP 2007 IDENTIFICATION OF IMPAIRED SURFACE WATERS 62-303 

Effective 9-4-07 

27 

104 115 6 346 356 27 

116 127 7 357 367 28 

128 139 8 368 378 29 

140 151 9 379 389 30 

152 163 10 390 401 31 

164 174 11 402 412 32 

175 186 12 413 423 33 

187 198 13 424 434 34 

199 209 14 435 445 35 

210 221 15 446 456 36 

222 232 16 457 467 37 

233 244 17 468 478 38 

245 255 18 479 489 39 

256 266 19 490 500 40 

267 278 20 

 (m) For waters listed pursuant to paragraph 62-303.320(6)(b), F.A.C., the 

water shall be delisted when the applicable criteria are met for at least three 

consecutive years and there are new data available for the same seasons in which the 

previous exceedances occurred. 

 (3) Any delisting of waters from the verified list shall be approved by order of 

the Secretary at such time as the requirements of this section are met. 

Specific Authority 403.061, 403.067 FS. Law Implemented 403.062, 403.067 FS. 

History–New 6-10-02, Amended 12-11-06, 9-4-07. 

62-303.810 Impairment of Interstate and Tribal Waters. 

The Department shall work with Alabama, Georgia, and federally recognized Indian 

Tribes in Florida to share information about their assessment methodology and share 

water quality data for waters that form state boundaries or flow into Florida. In cases 

where assessments are different for the same water body, the Department shall, to the 

extent practical, work with the appropriate state, Indian Tribe and EPA to determine why 

the assessments were different. 

Specific Authority 403.061, 403.067 FS. Law Implemented 403.062, 403.067 FS. 

History – New 6-10-02, Repromulgated 1-2-07.