Marys Pond
Plymouth County, MassachusettsView mapDirections
MassDEP publishes the water-quality measurements for Marys Pond. Here is what has been measured.
- Mesotrophic
- Impaired · Mercury
- Limited data
Marys Pond in Plymouth County, Massachusetts has water-quality measurements published by MassDEP, shown here as reported. Chlorophyll-a (algae): 2.6 µg/L.
Marys Pond is a mesotrophic lake in Plymouth County, Massachusetts. Compared to the 11 other monitored lakes in Plymouth County, Marys Pond ranks #3 for water quality.
Source: EPA Water Quality Portal sampling records, MassDEP, last sampled 2018-09-06. 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. Marys Pond is listed impaired under Clean Water Act §303(d) (IR 5) for mercury. Check local advisories before you swim.
Whether Marys Pond is safe to swim in today is a call for the Massachusetts Department of Environmental Protection and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Marys Pond
These are the measurements MassDEP publishes for Marys Pond, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
No clarity data. Chlorophyll-a 2.6 µg/L. TSI 40.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | No reading How deep a black-and-white disk stays visible from the surface. Higher is clearer. | |
| Total phosphorus | No reading The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. | |
| Chlorophyll-a (algae) | 2.6µg/L | Good GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 40 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Marys Pond
Answers come straight from the public measurements and survey records on this page.
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Fishing Marys Pond
EPA Impairment Status
Marys Pond is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 5).
Causes of impairment
Designated uses not supporting: Fish consumption.
Source: EPA ATTAINS assessment unit MA95100 · Official waterbody report
Nearby Lakes in Plymouth County
Frequently asked questions about Marys Pond
Where is Marys Pond?
- Marys Pond is a lake in Plymouth County, Massachusetts. Its water-quality measurements are published by MassDEP and shown on this page as reported.
What is the water quality of Marys Pond?
- Marys Pond in Plymouth County, Massachusetts has water-quality measurements published by MassDEP, shown here as reported. Chlorophyll-a (algae): 2.6 µg/L.
Is Marys Pond safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Marys Pond is listed impaired under Clean Water Act §303(d) (IR 5) for mercury. Check local advisories before you swim.
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Where this data comes from
3 measurements from 1 monitoring station, 2018. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Massachusetts Department of Environmental Protection (MassDEP)
MASSDEP3 samples · 2018
Analytical methods
- 445.0 ~ EPA; Chlorophyll and Pheophytin in Algae by Fluorescence
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