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LakeQuality

Twin Lake South Lobe

D
Grade D — Nutrient-rich
Nutrient-rich · #14 of 15 lakes in the county · 2 ft clear · Hypereutrophic · from F
Hypereutrophic

Twin Lake South Lobe in Okaloosa County, Florida has a water quality grade of D (Nutrient-rich). Water clarity: 2 ft visibility. Phosphorus: 440 µg/L.

Clarity
2 ft
Typical in August
84°F
Type
Hypereutrophic
Trend
Declining

Grade D measures nutrients and algae, not whether this is a good place for a cabin trip. Cabins and rentals near Twin Lake South Lobe

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Twin Lake South Lobe is a highly nutrient-loaded hypereutrophic lake in Okaloosa County, Florida. Water quality is graded D based on 1 sampling years through 2025. Overall water quality is declining over recent sampling years. Compared to the 14 other monitored lakes in Okaloosa County, Twin Lake South Lobe ranks #14 for water quality.

Source: EPA Water Quality Portal sampling records, FDEP, last sampled 2025-08-27. Grade methodology: LakeQuality methodology.

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Swimming Safety

Grade only

Bacteria A · advisory

Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.

A
Bacteria swim-safety grade: A
from E. coli testing · 11 samples, 2 seasons

Based on E. coli testing, Twin Lake South Lobe never exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 0% of 11 samples across 2 seasons.

This is a historical summary of past testing, not a current condition — bacteria levels change quickly, especially after rain. Always check Florida’s current beach and health-department advisories before swimming.

Get alerts for Twin Lake South Lobe

Water Quality Grade: D (Nutrient-rich)

Very murky, less than 2 ft of visibility. Phosphorus level: 440 µg/L. Trophic State Index: 80.

MetricValueGrade
Water Clarity (Secchi Depth)2 ftNot graded
Phosphorus440 µg/LPoor
Chlorophyll-a (Algae)No recent samples
Trophic State Index (TSI)80Hypereutrophic

Very high nutrients, dense algae, poor clarity

Where to stay near Twin Lake South Lobe

Compare lakeside cabins, hotels, and vacation rentals near Twin Lake South Lobe in Okaloosa County, Florida — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water. The water-quality grade measures nutrients and algae, not lodging — cabins and rentals around Twin Lake South Lobe are listed below.

Top-rated places to stay near Twin Lake South Lobe

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Planning a whole trip? See where to stay at Florida’s top lakes →

Water Temperature

Twin Lake South Lobe typically sits around 84°F at the surface in August. Summer average is about 84°F. Usually warmest in Jun (about 84°F) and coldest in Jan (about 58°F). These are typical values by month — not a live reading.

Jan
58°
Feb
61°
Mar
62°
Apr
73°
May
79°
Jun
84°
Jul
84°
Aug
84°
Sep
81°
Oct
70°
Nov
62°
Dec
61°

Typical surface water temperature by month, from 45 field readings (20212025) via the EPA Water Quality Portal. See the full Twin Lake South Lobe water temperature breakdown →

Fishing Twin Lake South Lobe

Based on 6 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Declining-0.05 m/yr6
Phosphorus Stable+2.57 µg/L/yr6
See year-by-year chart →

EPA Impairment Status

Twin Lake South Lobe is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 5).

Causes of impairment

MercuryPathogens (E. coli, fecal)

A Total Maximum Daily Load (TMDL) plan has been approved.

Source: EPA ATTAINS assessment unit FL917A · Official waterbody report · Matched by proximity (1.19 km)

County Ranking

Ranked #14 of 15 lakes in Okaloosa County

Nearby Lakes in Okaloosa County

Frequently asked questions about Twin Lake South Lobe

Where is Twin Lake South Lobe?

Twin Lake South Lobe is a lake in Okaloosa County, Florida. LakeQuality grades it D for nutrients and algae. The letter is not a swimming clearance.

What is the water quality grade for Twin Lake South Lobe?

Twin Lake South Lobe in Okaloosa County, Florida has a water quality grade of D (Nutrient-rich). Water clarity: 2 ft visibility. Phosphorus: 440 µg/L.

Is Twin Lake South Lobe safe to swim in?

Based on E. coli testing, Twin Lake South Lobe never exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 0% of 11 samples across 2 seasons. That works out to a bacteria swim-safety grade of A — a historical summary of past testing, not a current reading. Twin Lake South Lobe has a water quality grade of D (Nutrient-rich). Bacteria levels can spike quickly after heavy rain, so always check Florida's current beach and health-department advisories before you swim.

What is the water temperature of Twin Lake South Lobe?

Twin Lake South Lobe typically sits around 84°F at the surface in August, from 45 EPA Water Quality Portal field readings (2021–2025). That is a typical value for the month, not a live reading.

Where this data comes from

48 measurements from 2 monitoring stations, 2021–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.

Collected and reported by

  • FL Dept. of Environmental Protection, Northwest District21FLPNS_WQX48 samples · 2021–2025
Monitoring station identifiers (2)

Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.

Other records on this page

Impairment status from EPA ATTAINS 303(d) database