Long Pond
Barnstable County, MassachusettsView mapDirections
MassDEP publishes the water-quality measurements for Long Pond. Here is what has been measured.
- Mesotrophic
- 38 ft max depth
- Limited data
Long Pond in Barnstable County, Massachusetts has water-quality measurements published by MassDEP, shown here as reported. Chlorophyll-a (algae): 6 µg/L.
Long Pond is a mesotrophic lake in Barnstable County, Massachusetts with an estimated average depth of about 38 feet. Overall water quality is declining over recent sampling years. Compared to the 7 other monitored lakes in Barnstable County, Long Pond ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, MassDEP, last sampled 2018-09-26. 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 Long 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 Long Pond
These are the measurements MassDEP publishes for Long 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 6 µg/L. TSI 48.
| 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) | 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. | 48 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Long Pond
Answers come straight from the public measurements and survey records on this page.
Lake Details
Max depth
~38 ft est.
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Massachusetts has not published bathymetry for Long Pond.
Lake Size & Watershed
Watershed (drainage) area
0 sq mi
HydroLAKES / HydroSHEDS
Surface area
47 acres
HydroLAKES / HydroSHEDS
Shoreline
1.6 mi
HydroLAKES / HydroSHEDS
Elevation
69 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.
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Stays near Long Pond
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Fishing Long Pond
Water quality readings over time
2 seasons of samples on record (2018–2020). Calling a direction takes at least 4 years of the same measurement.
Chlorophyll-a
Worsening+23.2 µg/L/yr2 years
Nearby Lakes in Barnstable County
Frequently asked questions about Long Pond
Where is Long Pond?
- Long Pond is a lake in Barnstable County, Massachusetts. Its water-quality measurements are published by MassDEP and shown on this page as reported.
What is the water quality of Long Pond?
- Long Pond in Barnstable County, Massachusetts has water-quality measurements published by MassDEP, shown here as reported. Chlorophyll-a (algae): 6 µg/L.
Is Long Pond safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
How deep is Long Pond?
- No published bathymetric survey covers Long Pond, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 38 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate.
Explore Long Pond across LakeQuality
Planning a trip around Cape Cod?
Long Pond is about 27 miles from Cape Cod 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 Cape Cod →More lakes in Massachusetts
Other Lakes in Massachusetts
Mesotrophic Lakes in Massachusetts
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
Lake size & watershed from HydroLAKES (HydroSHEDS)