Halfmoon Pond-Deep Spot
Sullivan County, New HampshireView mapDirections
NHDES publishes the water-quality measurements for Halfmoon Pond-Deep Spot. Here is what has been measured.
- Impaired · Mercury
- Public access
- Limited data
Halfmoon Pond-Deep Spot in Sullivan County, New Hampshire has water-quality measurements published by NHDES, shown here as reported. Phosphorus: 14.6 µg/L.
Halfmoon Pond-Deep Spot is a lake in Sullivan County, New Hampshire. Limited fish-species data available. Public access is available.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2024-07-23. Methodology: how these readings are compared.
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Halfmoon Pond-Deep Spot is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, oxygen depletion (low DO), pH / acidity. Check local advisories before you swim.
Whether Halfmoon Pond-Deep Spot 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 Halfmoon Pond-Deep Spot
These are the measurements NHDES publishes for Halfmoon Pond-Deep Spot, 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 14.6 µg/L. TSI 43.
| 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 | 14.6µg/L | Measured, not scored The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. |
| 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. | 43 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Halfmoon Pond-Deep Spot
Answers come straight from the public measurements and survey records on this page.
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Fishing Halfmoon Pond-Deep Spot
EPA Impairment Status
Halfmoon Pond-Deep Spot is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Designated uses not supporting: Aquatic life, Fish consumption.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit NHLAK700030201-02 · Official waterbody report
Nearby Lakes in Sullivan County
Frequently asked questions about Halfmoon Pond-Deep Spot
Where is Halfmoon Pond-Deep Spot?
- Halfmoon Pond-Deep Spot is a lake in Sullivan County, New Hampshire. Its water-quality measurements are published by NHDES and shown on this page as reported.
What is the water quality of Halfmoon Pond-Deep Spot?
- Halfmoon Pond-Deep Spot in Sullivan County, New Hampshire has water-quality measurements published by NHDES, shown here as reported. Phosphorus: 14.6 µg/L.
Is Halfmoon Pond-Deep Spot safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Halfmoon Pond-Deep Spot is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, oxygen depletion (low DO), pH / acidity. Check local advisories before you swim.
Can I fish at Halfmoon Pond-Deep Spot?
- Public access to Halfmoon Pond-Deep Spot 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
2 measurements from 1 monitoring station, 2024. Retrieved from the EPA Water Quality Portal on 2026-08-21.
Collected and reported by
- New Hampshire Department Of Environmental Services (BEACH)
111133002 samples · 2024
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.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database