Main Section Lake
Clinton County, New YorkView mapDirections
Nutrients and algae sit mid-range for this region.
↓ down from A at the last regrade
- Mesotrophic
- Impaired · Mercury
- #3 of 3 in the county
- Public access
Main Section Lake in Clinton County, New York has a water quality grade of C (Fair). Water clarity: 14.8 ft visibility. Phosphorus: 12.1 µg/L. Chlorophyll-a (algae): 4.7 µg/L.
- Clarity
- 14.8 ft
- Typical in September
- 66°F
- Type
- Mesotrophic
- Phosphorus
- 12.1 µg/L
- Chlorophyll-a
- 4.7 µg/L
- Trend
- ↓ Declining
- Public access
- Yes
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Main Section Lake is a mesotrophic lake in Clinton County, New York. Water quality is graded C based on 2 sampling years through 2024. Overall water quality is declining over recent sampling years. Limited fish-species data available. Public access is available with 2 public boat landings. Compared to the 2 other monitored lakes in Clinton County, Main Section Lake ranks #3 for water quality.
Source: EPA Water Quality Portal sampling records, NYSDEC, last sampled 2024-10-25. Grade methodology: LakeQuality methodology.
What Main Section Lake is good for
From access and monitoring records, not editorial picks.
- Clear water14.8 ft of visibility
- Boat launch2 documented ramps
Swimming Safety
Grade onlyModerate
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.
The C is nutrients and algae, not a swimming clearance. Main Section Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, nutrients (phosphorus, nitrogen), pCBs. Check local advisories before you swim.
Water Quality Grade: C (Fair)
Good clarity, visible to about 14.8 ft. Phosphorus 12.1 µg/L. Chlorophyll-a 4.7 µg/L. TSI 41. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 14.8 ft | Not graded |
| Phosphorus | 12.1 µg/L | Good |
| Chlorophyll-a (Algae) | 4.7 µg/L | Fair |
| Trophic State Index (TSI) | 41 | Mesotrophic |
Moderate nutrients, good water quality
Water Temperature
Main Section Lake typically sits around 66°F at the surface in September. Summer average is about 67°F. Usually warmest in Aug (about 72°F) and coldest in Apr (about 43°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 2,906 field readings (2010–2023) via the EPA Water Quality Portal. See the full Main Section Lake water temperature breakdown →
Recreation & Access
- PeruPublic
- Peace Point ParkPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Fishing Main Section Lake
Water Quality Trend: ↓ Declining
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.21 m/yr | 4 |
| Phosphorus | → Stable | -0.01 µg/L/yr | 5 |
| Chlorophyll-a | → Stable | -0.05 µg/L/yr | 3 |
EPA Impairment Status
Main Section Lake is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 5).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit NY1001-0001 · Official waterbody report · Matched by proximity (0.63 km)
Regulated Pollution Sources Nearby
7 EPA-permitted facilities operate within about 5 miles of Main Section Lake under Clean Water Act (NPDES) discharge permits, including 1 classified by the EPA as major discharger. 2 facilities have a reported Clean Water Act violation in the past three years.
- Plattsburgh Water Pollution Control PlantPlattsburgh · 1.4 mi away · NPDES NY0026018MajorRecent violation
- Country Sky Mobile Home ParkBeekmantown · 3.7 mi away · NPDES NY0240133Recent violation
- Champlain Park Sd WwtpPlattsburgh · 1.1 mi away · NPDES NY0020834
- Plattsburgh Coal Tar ConfinemePlattsburgh · 1.8 mi away · NPDES NY0183628
- Plattsburgh Intern'Al AirportPlattsburgh · 3.4 mi away · NPDES NY0217905
- Dr Palmer Veterinary ClinicPlattsburgh · 3.5 mi away · NPDES NY0230901
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.
County Ranking
Ranked #3 of 3 lakes in Clinton County
Nearby Lakes in Clinton County
Frequently asked questions about Main Section Lake
Where is Main Section Lake?
- Main Section Lake is a lake in Clinton County, New York. LakeQuality grades it C for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Main Section Lake?
- Main Section Lake in Clinton County, New York has a water quality grade of C (Fair). Water clarity: 14.8 ft visibility. Phosphorus: 12.1 µg/L. Chlorophyll-a (algae): 4.7 µg/L.
Is Main Section Lake safe to swim in?
- The C is nutrients and algae, not a swimming clearance. Main Section Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, nutrients (phosphorus, nitrogen), pCBs. Check local advisories before you swim.
What is the water temperature of Main Section Lake?
- Main Section Lake typically sits around 66°F at the surface in September, from 2,906 EPA Water Quality Portal field readings (2010–2023). That is a typical value for the month, not a live reading.
Are there boat ramps on Main Section Lake?
- Main Section Lake has 2 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Peru, Peace Point Park. Public access is listed as yes.
Explore Main Section Lake across LakeQuality
Species activity outlook by water temperature and season
Top lakes and where to stay in the Adirondacks area
Where to stay at New York's top lakes, each with its grade
Moderate nutrients, good water quality
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Other Grade C Lakes in New York
Mesotrophic Lakes in New York
Where this data comes from
211 measurements from 1 monitoring station, 2020–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Vermont Dept of Environmental Conservation
1VTDECWQ211 samples · 2020–2024
Analytical methods
- EPA approved Alternate Test Procedure for 4500 P H. Has a 28 day hold without acid preservation.
- 445.0 ~ EPA; Chlorophyll and Pheophytin in Algae by Fluorescence
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
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Named boat-access points from the USGS National Boat Ramps inventory