Lake Plymouth
Lake Plymouth in Litchfield County, Connecticut is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 3.5 ft visibility. Surface area: 45.5 acres.
- Clarity
- 3.5 ft
- Area
- 46 acres
Why Lake Plymouth has no grade
We grade a lake only when its monitoring record clears the evidence bar: at least three phosphorus or chlorophyll-a samples in the last ten years, scored against EPA National Lakes Assessment thresholds for this lake’s ecoregion. For Lake Plymouth, the only measurement available is water clarity, which is not a water-quality indicator on its own — EPA's National Lakes Assessment does not grade clarity. Sampling here has recorded water clarity, but not phosphorus and algae (chlorophyll-a).
Not Rated is not an F. It is EPA Integrated Reporting Category 3 — insufficient information. The water here may be excellent or poor; nobody has measured enough of it to say. Everything below that has been measured is still reported on this page.
Sampling is run by your state environmental agency and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
Lake Plymouth is a 46-acre lake in Litchfield County, Connecticut.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2025-09-27. Grade methodology: LakeGrade methodology.
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Swimming Safety
Not ratedLimited data
Not rated for swimming — there is not enough monitoring data to judge this lake
Water quality measurements for Lake Plymouth
These readings exist but do not meet the evidence bar for an A–F grade — see why.
Murky, only visible to about 3.5 ft. Trophic State Index: 59.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 3.5 ft | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 59 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Lake Plymouth
Compare lakeside cabins, hotels, and vacation rentals near Lake Plymouth in Litchfield County, Connecticut — 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 Plymouth
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Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 46 acres |
No bathymetric survey has been published for Lake Plymouth, so its depth is not documented here.
Fishing Lake Plymouth
Reservoir Info (USACE NID)
Lake Plymouth is a man-made reservoir impounded by the Lake Plymouth Dam (completed 1900), built primarily for recreation on the Todd Hollow Bk Trib; earth-type dam, 11 ft tall and 331 ft long.
- Surface area
- 45.5 ac
- Normal storage
- 128 ac-ft
- Max storage
- 128 ac-ft
- Drainage area
- 0.35 sq mi
- Hazard class
- Significant
- Owner
- Lake Plymouth Community Assoc Inc.
Source: USACE National Inventory of Dams, NID ID CT00290 · Operator website
Graded lakes near Lake Plymouth
Lake Plymouth has no grade, but these lakes within a short drive do.
Nearby Lakes in Litchfield County
Frequently asked questions about Lake Plymouth
Where is Lake Plymouth?
- Lake Plymouth is a lake in Litchfield County, Connecticut. LakeQuality has not rated this lake (UNRATED) — there is not enough recent sampling to assign a letter.
What is the water quality grade for Lake Plymouth?
- Lake Plymouth in Litchfield County, Connecticut is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 3.5 ft visibility. Surface area: 45.5 acres.
Is Lake Plymouth safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Lake Plymouth is not rated for water quality — its monitoring record does not meet the evidence bar. Always check local health department advisories before swimming.
Explore Lake Plymouth across LakeGrade
More Connecticut Lake Rankings
Other Lakes in Connecticut
Eutrophic Lakes in Connecticut
Where this data comes from
8 measurements from 1 monitoring station, 2025. Retrieved from the EPA Water Quality Portal on 2026-08-21.
Collected and reported by
- CT DEEP Volunteer Water Monitoring Program (Volunteer)
CTVOLMON8 samples · 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.