Lake Seminole
Pinellas County, Florida320 acresView mapDirections
Florida DEP publishes the water-quality measurements for Lake Seminole. Here is what has been measured.
- Hypereutrophic
- Impaired · Algal growth
- Public access
- Limited data
Lake Seminole in Pinellas County, Florida has water-quality measurements published by Florida DEP, shown here as reported. Water clarity: 1 ft visibility. Phosphorus: 63 µg/L. Surface area: 320 acres.
Lake Seminole is a 320-acre highly nutrient-loaded hypereutrophic lake in Pinellas County, Florida. Overall water quality is improving over recent sampling years. Limited fish-species data available. Public access is available with 1 public boat landing. Compared to the 33 other monitored lakes in Pinellas County, Lake Seminole ranks #18 for water quality.
Source: EPA Water Quality Portal sampling records, FDEP, last sampled 2025-02-13. Methodology: how these readings are compared.
Lake Seminole covers about 320 acres in Pinellas County. It has one public boat landing. Vrbo is where to look for cabins and lake homes around Lake Seminole, and Booking.com and Expedia search hotels near the lake for your dates.
What Lake Seminole is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
Swimming conditions
Readings onlyRecreation use not supported
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.
Based on E. coli testing, Lake Seminole rarely exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 4.3% of 23 samples across 7 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.
Whether Lake Seminole 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 Seminole
These are the measurements Florida DEP publishes for Lake Seminole, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Very murky, less than 1 ft of visibility. Phosphorus 63 µg/L. TSI 71.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 1ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 63µg/L | Poor 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. | 71 | Hypereutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Very high nutrients, dense algae, poor clarity
Ask about Lake Seminole
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Lake Seminole typically sits around 76°F at the surface in October. Summer average is about 88°F. Usually warmest in Jun (about 89°F) and coldest in Jan (about 63°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (63°F) to its warmest (89°F).
Typical surface water temperature by month, from 166 field readings (2010–2025) via the EPA Water Quality Portal.
Lake Details
Surface area
320 acres
Public access
Yes
Listed by Florida DEP
No bathymetric survey has been published for Lake Seminole, so its depth is not documented here.
Recreation & Access
- Lake Seminole Park and Public Boat RampPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays near Lake Seminole
Compare lakeside cabins, hotels, and vacation rentals near Lake Seminole in Pinellas 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 readings cover nutrients and algae, not lodging. Cabins and rentals around Lake Seminole are listed below.
Top-rated places to stay near Lake Seminole
Prices for Oct 9–11, 4 adults. Change dates on the map below.
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 →
Follow Lake Seminole’s readings
Email me when new measurements post for this lake. Updates stay free.
Or email
Fishing Lake Seminole
Water Quality Trend: Improving
Based on 5 years of monitoring (2020–2024).
Water clarity
Improving5 years
Phosphorus
Improving-14.1 µg/L/yr5 years
Reservoir Info (USACE NID)
Lake Seminole is a man-made reservoir impounded by the Lake Seminole Dam (completed 1949), built primarily for recreation on the Long Bayou; earth-type dam, 15 ft tall and 2,000 ft long.
- Surface area
- 320 ac
- Normal storage
- 3,000 ac-ft
- Max storage
- 4,800 ac-ft
- Drainage area
- 0 sq mi
- Hazard class
- Low
- Owner
- PINELLAS COUNTY
All listed purposes: Recreation;Other.
Source: USACE National Inventory of Dams, NID ID FL00429 · Operator website
EPA Impairment Status
Lake Seminole is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 4B).
Causes of impairment
Designated uses not supporting: Aquatic life, Recreation.
Source: EPA ATTAINS assessment unit FL1618 · Official waterbody report
Regulated Pollution Sources Nearby
5 EPA-permitted facilities operate within about 5 miles of Lake Seminole under Clean Water Act (NPDES) discharge permits, including 5 classified by the EPA as major dischargers.
- Seminole, City OfSeminole · 1.4 mi away · NPDES FLS648388Major
- Redington Beach, Town OfRedington Beach · 2.6 mi away · NPDES FLS648477Major
- Madeira Beach, City OfMadeira Beach · 3.3 mi away · NPDES FLS648272Major
- North Redington Beach, Town OfNorth Redington Beach · 3.3 mi away · NPDES FLS648469Major
- Redington Shores, Town OfRedington Shores · 3.4 mi away · NPDES FLS648485Major
Facilities permitted to discharge under the Clean Water Act within ~5 miles; proximity does not by itself mean a facility affects this lake. Source: EPA ECHO (ICIS-NPDES), as of 2026-07.
Nearby Lakes in Pinellas County
Frequently asked questions about Lake Seminole
Where is Lake Seminole?
- Lake Seminole is a lake in Pinellas 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 Seminole?
- Lake Seminole in Pinellas County, Florida has water-quality measurements published by Florida DEP, shown here as reported. Water clarity: 1 ft visibility. Phosphorus: 63 µg/L. Surface area: 320 acres.
Is Lake Seminole safe to swim in?
- Based on E. coli testing, Lake Seminole rarely exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 4.3% of 23 samples across 7 seasons. That is a historical summary of past bacteria testing, not a current reading and not a swimming clearance. Bacteria levels can spike quickly after heavy rain, so whether Lake Seminole is safe to swim in today is a call for Florida's water agency and the county health department; check their current beach advisories before you swim.
What is the water temperature of Lake Seminole?
- Lake Seminole typically sits around 76°F at the surface in October, from 166 EPA Water Quality Portal field readings (2010–2025). That is a typical value for the month, not a live reading.
Are there boat ramps on Lake Seminole?
- Lake Seminole has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Lake Seminole Park and Public Boat Ramp. Public access is listed as yes.
Can I fish at Lake Seminole?
- Lake Seminole has 1 documented boat landing in the USGS National Boat Ramps inventory. Seasons, size and bag limits, and whether you need a license are set by Florida's fish and wildlife agency, so check its current regulations before you go.
Explore Lake Seminole across LakeQuality
More lakes in Florida
Other Lakes in Florida
Hypereutrophic Lakes in Florida
Where this data comes from
12 measurements from 1 monitoring station, 2023–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Submitting organization not recorded for these samples12 samples · 2023–2025
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
Impairment status from EPA ATTAINS 303(d) database
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Named boat-access points from the USGS National Boat Ramps inventory