Dias Lake
Dias Lake in Volusia County, Florida has a water quality grade of B (Good). Water clarity: 3.3 ft visibility. Phosphorus: 31.4 µg/L.
- Clarity
- 3.3 ft
- Typical in August
- 88°F
- Type
- Eutrophic
- Trend
- ↑ Improving
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Dias Lake is a productive, nutrient-rich eutrophic lake in Volusia County, Florida. Water quality is graded B based on 1 sampling years through 2025. Overall water quality is improving over recent sampling years. Compared to the 29 other monitored lakes in Volusia County, Dias Lake ranks #9 for water quality.
Source: EPA Water Quality Portal sampling records, FDEP, last sampled 2025-02-11. Grade methodology: LakeQuality methodology.
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Swimming Safety
Grade onlyLow algae
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
Water Quality Grade: B (Good)
Very murky, less than 3.3 ft of visibility. Phosphorus level: 31.4 µg/L. Trophic State Index: 57.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 3.3 ft | Not graded |
| Phosphorus | 31.4 µg/L | Good |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 57 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Dias Lake
Compare lakeside cabins, hotels, and vacation rentals near Dias Lake in Volusia 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 Dias Lake
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
Planning a whole trip? See where to stay at Florida’s top lakes →
Water Temperature
Dias Lake typically sits around 88°F at the surface in August. Summer average is about 87°F. Usually warmest in Aug (about 88°F) and coldest in Dec (about 66°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 59 field readings (2010–2025) via the EPA Water Quality Portal. See the full Dias Lake water temperature breakdown →
Fishing Dias Lake
Water Quality Trend: ↑ Improving
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.05 m/yr | 5 |
| Phosphorus | → Stable | +0.08 µg/L/yr | 5 |
EPA Impairment Status
Dias Lake is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 4A).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit FL2667A · Official waterbody report
County Ranking
Ranked #9 of 30 lakes in Volusia County
Nearby Lakes in Volusia County
Frequently asked questions about Dias Lake
Where is Dias Lake?
- Dias Lake is a lake in Volusia County, Florida. LakeQuality grades it B for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Dias Lake?
- Dias Lake in Volusia County, Florida has a water quality grade of B (Good). Water clarity: 3.3 ft visibility. Phosphorus: 31.4 µg/L.
Is Dias Lake safe to swim in?
- Good for swimming, clear water with low algae levels. Dias Lake has a water quality grade of B (Good). Always check local health department advisories before swimming.
What is the water temperature of Dias Lake?
- Dias Lake typically sits around 88°F at the surface in August, from 59 EPA Water Quality Portal field readings (2010–2025). That is a typical value for the month, not a live reading.
Explore Dias Lake across LakeQuality
Planning a trip around Fort Matanzas?
Dias Lake is about 38 miles from Fort Matanzas National Monument. Crowds there swing hard by season, so the month you pick changes both how busy the park is and what lodging costs.
Best time to visit Fort Matanzas →More Florida Lake Rankings
Other Grade B Lakes in Florida
Eutrophic Lakes in Florida
Where this data comes from
62 measurements from 1 monitoring station, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Submitting organization not recorded for these samples62 samples · 2020–2025
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.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database