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LakeQuality

Dunl Lake

B
Grade B — Good
Good · #3 of 4 lakes in the county · 14.8 ft clear · Oligotrophic · from A
Limited DataOligotrophic

Dunl Lake in Washington County, Florida has a water quality grade of B (Good). Water clarity: 14.8 ft visibility. Phosphorus: 4 µg/L.

Clarity
14.8 ft
Typical in August
87°F
Type
Oligotrophic
Trend
Declining

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Dunl Lake is a cold, clear oligotrophic lake in Washington County, Florida. Water quality is graded B based on 1 sampling years through 2020. Overall water quality is declining over recent sampling years. Compared to the 3 other monitored lakes in Washington County, Dunl Lake ranks #3 for water quality.

Source: EPA Water Quality Portal sampling records, FDEP, last sampled 2020-08-04. Grade methodology: LakeQuality methodology.

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Swimming Safety

Grade only

Limited data

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.

Good for swimming, clear water with low algae levels

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Water Quality Grade: B (Good)

Good clarity, visible to about 14.8 ft. Phosphorus level: 4 µg/L. Trophic State Index: 31.

MetricValueGrade
Water Clarity (Secchi Depth)14.8 ftNot graded
Phosphorus4 µg/LGood
Chlorophyll-a (Algae)No recent samples
Trophic State Index (TSI)31Oligotrophic

Low nutrients, clear water, excellent for swimming

Where to stay near Dunl Lake

Compare lakeside cabins, hotels, and vacation rentals near Dunl Lake in Washington 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.

Top-rated places to stay near Dunl Lake

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

Water Temperature

Dunl Lake typically sits around 87°F at the surface in August. Summer average is about 84°F. Usually warmest in Aug (about 87°F) and coldest in Jan (about 62°F). These are typical values by month — not a live reading.

Jan
62°
Feb
Mar
Apr
May
73°
Jun
83°
Jul
82°
Aug
87°
Sep
Oct
79°
Nov
62°
Dec

Typical surface water temperature by month, from 20 field readings (20192020) via the EPA Water Quality Portal. See the full Dunl Lake water temperature breakdown →

Fishing Dunl Lake

Based on 2 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Declining-1 m/yr2
Phosphorus Declining+1 µg/L/yr2

County Ranking

Ranked #3 of 4 lakes in Washington County

Nearby Lakes in Washington County

Frequently asked questions about Dunl Lake

Where is Dunl Lake?

Dunl Lake is a lake in Washington County, Florida. LakeQuality grades it B for nutrients and algae. The letter is not a swimming clearance.

What is the water quality grade for Dunl Lake?

Dunl Lake in Washington County, Florida has a water quality grade of B (Good). Water clarity: 14.8 ft visibility. Phosphorus: 4 µg/L.

Is Dunl Lake safe to swim in?

Good for swimming, clear water with low algae levels. Dunl Lake has a water quality grade of B (Good). Always check local health department advisories before swimming.

What is the water temperature of Dunl Lake?

Dunl Lake typically sits around 87°F at the surface in August, from 20 EPA Water Quality Portal field readings (2019–2020). That is a typical value for the month, not a live reading.

Where this data comes from

8 measurements from 1 monitoring station, 2020. Retrieved from the EPA Water Quality Portal on 2026-08-02.

Collected and reported by

  • Submitting organization not recorded for these samples8 samples · 2020
Monitoring station identifiers (1)

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.