Mirror Lake
Mirror Lake in Seminole County, Florida has a water quality grade of B (Good). Water clarity: 7.2 ft visibility. Phosphorus: 20 µg/L.
- Clarity
- 7.2 ft
- Typical in July
- 88°F
- Type
- Mesotrophic
- Trend
- ↑ Improving
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Mirror Lake is a mesotrophic lake in Seminole 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 121 other monitored lakes in Seminole County, Mirror Lake ranks #14 for water quality.
Source: EPA Water Quality Portal sampling records, FDEP, last sampled 2025-07-22. Grade methodology: LakeQuality methodology.
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Swimming Safety
Grade onlyLimited 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
Water Quality Grade: B (Good)
Moderate clarity, visible to about 7.2 ft. Phosphorus level: 20 µg/L. Trophic State Index: 48.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 7.2 ft | Not graded |
| Phosphorus | 20 µg/L | Good |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 48 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Mirror Lake
Compare lakeside cabins, hotels, and vacation rentals near Mirror Lake in Seminole 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 Mirror Lake
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Planning a whole trip? See where to stay at Florida’s top lakes →
Water Temperature
Mirror Lake typically sits around 88°F at the surface in July. Summer average is about 86°F. Usually warmest in Jul (about 88°F) and coldest in Jan (about 63°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 75 field readings (2010–2025) via the EPA Water Quality Portal. See the full Mirror Lake water temperature breakdown →
Fishing Mirror Lake
Water Quality Trend: ↑ Improving
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.2 m/yr | 6 |
| Phosphorus | ↑ Improving | -7.5 µg/L/yr | 5 |
EPA Impairment Status
Mirror 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 FL3004A · Official waterbody report · Matched by proximity (1.97 km)
County Ranking
Ranked #14 of 122 lakes in Seminole County
Nearby Lakes in Seminole County
Frequently asked questions about Mirror Lake
Where is Mirror Lake?
- Mirror Lake is a lake in Seminole County, Florida. LakeQuality grades it B for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Mirror Lake?
- Mirror Lake in Seminole County, Florida has a water quality grade of B (Good). Water clarity: 7.2 ft visibility. Phosphorus: 20 µg/L.
Is Mirror Lake safe to swim in?
- Good for swimming, clear water with low algae levels. Mirror Lake has a water quality grade of B (Good). Always check local health department advisories before swimming.
What is the water temperature of Mirror Lake?
- Mirror Lake typically sits around 88°F at the surface in July, from 75 EPA Water Quality Portal field readings (2010–2025). That is a typical value for the month, not a live reading.
Explore Mirror Lake across LakeQuality
More Florida Lake Rankings
Other Grade B Lakes in Florida
Mesotrophic Lakes in Florida
Where this data comes from
40 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 samples40 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