Lake Markham
Seminole County, FloridaView mapDirections
Florida DEP publishes the water-quality measurements for Lake Markham. Here is what has been measured.
- Mesotrophic
- 36 ft max depth
- Limited data
Lake Markham in Seminole County, Florida has water-quality measurements published by Florida DEP, shown here as reported. Water clarity: 5.8 ft visibility. Phosphorus: 8 µg/L.
Lake Markham is a mesotrophic lake in Seminole County, Florida with an estimated average depth of about 36 feet. Water clarity is declining over recent sampling years. Compared to the 121 other monitored lakes in Seminole County, Lake Markham ranks #26 for water quality.
Source: EPA Water Quality Portal sampling records, FDEP, last sampled 2025-05-13. Methodology: how these readings are compared.
Swimming conditions
Readings onlyLimited data
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Lake Markham is safe to swim in today is a call for the Florida Department of Environmental Protection and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Lake Markham
These are the measurements Florida DEP publishes for Lake Markham, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Murky, only visible to about 5.8 ft. Phosphorus 8 µg/L. TSI 43.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 5.8ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 8µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | No reading The green pigment in algae — a direct measure of how much algae is in the water. | |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 43 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Lake Markham
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Lake Markham typically sits around 72°F at the surface in November. 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.
Column height runs from this lake’s coldest month (66°F) to its warmest (88°F).
Typical surface water temperature by month, from 52 field readings (2010–2025) via the EPA Water Quality Portal. See the full Lake Markham water temperature breakdown →
Lake Details
Max depth
~36 ft est.
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Florida has not published bathymetry for Lake Markham.
Lake Size & Watershed
Watershed (drainage) area
0 sq mi
HydroLAKES / HydroSHEDS
Surface area
59 acres
HydroLAKES / HydroSHEDS
Shoreline
1.7 mi
HydroLAKES / HydroSHEDS
Elevation
49 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth here is modelled, not surveyed — HydroLAKES v1.0 estimates lake depth from surrounding terrain rather than from soundings. Treat it as an approximation, and prefer a state bathymetric survey where one exists.
Stays via Stay22
Stays near Lake Markham
Compare lakeside cabins, hotels, and vacation rentals near Lake Markham 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 Lake Markham
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Planning a whole trip? See where to stay at Florida’s top lakes →
Follow Lake Markham’s readings
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Fishing Lake Markham
Water Quality Trend: Stable
Based on 5 years of monitoring (2020–2024).
Water clarity
Worsening5 years
Phosphorus
Improving-2.9 µg/L/yr5 years
Nearby Lakes in Seminole County
Frequently asked questions about Lake Markham
Where is Lake Markham?
- Lake Markham is a lake in Seminole County, Florida. Its water-quality measurements are published by Florida DEP and shown on this page as reported.
What is the water quality of Lake Markham?
- Lake Markham in Seminole County, Florida has water-quality measurements published by Florida DEP, shown here as reported. Water clarity: 5.8 ft visibility. Phosphorus: 8 µg/L.
Is Lake Markham safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
What is the water temperature of Lake Markham?
- Lake Markham typically sits around 72°F at the surface in November, from 52 EPA Water Quality Portal field readings (2010–2025). That is a typical value for the month, not a live reading.
How deep is Lake Markham?
- No published bathymetric survey covers Lake Markham, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 36 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate.
Explore Lake Markham across LakeQuality
Planning a trip around Canaveral?
Lake Markham is about 39 miles from Canaveral National Seashore. 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 Canaveral →More lakes in Florida
Other Lakes in Florida
Mesotrophic Lakes in Florida
Where this data comes from
39 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 samples39 samples · 2020–2025
Monitoring station identifiers (1)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.
Other records on this page
Lake size & watershed from HydroLAKES (HydroSHEDS)