Cobbetts Pond-Armstrong
Rockingham County, New HampshireView mapDirections
NHDES publishes the water-quality measurements for Cobbetts Pond-Armstrong. Here is what has been measured.
- Mesotrophic
- Public access
Cobbetts Pond-Armstrong in Rockingham County, New Hampshire has water-quality measurements published by NHDES, shown here as reported. Phosphorus: 19.1 µg/L.
Cobbetts Pond-Armstrong is a mesotrophic lake in Rockingham County, New Hampshire. Limited fish-species data available. Public access is available. Compared to the 50 other monitored lakes in Rockingham County, Cobbetts Pond-Armstrong ranks #31 for water quality.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2025-06-10. Methodology: how these readings are compared.
Swimming conditions
Readings onlyModerate algae
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 Cobbetts Pond-Armstrong is safe to swim in today is a call for the New Hampshire Department of Environmental Services and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Cobbetts Pond-Armstrong
These are the measurements NHDES publishes for Cobbetts Pond-Armstrong, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
No clarity data. Phosphorus 19.1 µg/L. TSI 47.
| 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 | 19.1µg/L | Fair 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. | 47 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
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Fishing Cobbetts Pond-Armstrong
Nearby Lakes in Rockingham County
Frequently asked questions about Cobbetts Pond-Armstrong
Where is Cobbetts Pond-Armstrong?
- Cobbetts Pond-Armstrong is a lake in Rockingham County, New Hampshire. Its water-quality measurements are published by NHDES and shown on this page as reported.
What is the water quality of Cobbetts Pond-Armstrong?
- Cobbetts Pond-Armstrong in Rockingham County, New Hampshire has water-quality measurements published by NHDES, shown here as reported. Phosphorus: 19.1 µg/L.
Is Cobbetts Pond-Armstrong safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Can I fish at Cobbetts Pond-Armstrong?
- Public access to Cobbetts Pond-Armstrong is listed as yes on the lake record. Seasons, size and bag limits, and whether you need a license are set by New Hampshire's fish and wildlife agency, so check its current regulations before you go.
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Where this data comes from
10 measurements from 1 monitoring station, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-21.
Collected and reported by
- New Hampshire Department Of Environmental Services (BEACH)
1111330010 samples · 2020–2025
Analytical methods
- 10-115-01-1 F ~ LACHAT; Total Phosphorus- Manual persulfate digest
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.