Round Pond-Deep Spot
Grafton County, New HampshireView mapDirections
NHDES publishes the water-quality measurements for Round Pond-Deep Spot. Here is what has been measured.
- Mesotrophic
- Impaired · Algal growth
Round Pond-Deep Spot in Grafton County, New Hampshire has water-quality measurements published by NHDES, shown here as reported. Phosphorus: 18.9 µg/L. Chlorophyll-a (algae): 8.3 µg/L.
Round Pond-Deep Spot is a mesotrophic lake in Grafton County, New Hampshire. Compared to the 26 other monitored lakes in Grafton County, Round Pond-Deep Spot ranks #26 for water quality.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2025-07-06. Methodology: how these readings are compared.
Swimming conditions
Readings onlyRecreation use not supported
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. Round Pond-Deep Spot is listed impaired under Clean Water Act §303(d) (IR 5) for algal growth, mercury, nutrients (phosphorus, nitrogen), oxygen depletion (low DO). Check local advisories before you swim.
Whether Round 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 Round Pond-Deep Spot
These are the measurements NHDES publishes for Round 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 18.9 µg/L. Chlorophyll-a 8.3 µg/L. TSI 49.
| 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 | 18.9µg/L | Fair GoodFairPoor |
| Chlorophyll-a (algae) | 8.3µg/L | Measured, not scored 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. | 49 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
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Fishing Round Pond-Deep Spot
EPA Impairment Status
Round 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, Recreation.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit NHLAK801030502-04 · Official waterbody report
Nearby Lakes in Grafton County
Frequently asked questions about Round Pond-Deep Spot
Where is Round Pond-Deep Spot?
- Round Pond-Deep Spot is a lake in Grafton County, New Hampshire. Its water-quality measurements are published by NHDES and shown on this page as reported.
What is the water quality of Round Pond-Deep Spot?
- Round Pond-Deep Spot in Grafton County, New Hampshire has water-quality measurements published by NHDES, shown here as reported. Phosphorus: 18.9 µg/L. Chlorophyll-a (algae): 8.3 µg/L.
Is Round Pond-Deep Spot safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Round Pond-Deep Spot is listed impaired under Clean Water Act §303(d) (IR 5) for algal growth, mercury, nutrients (phosphorus, nitrogen), oxygen depletion (low DO). Check local advisories before you swim.
Explore Round Pond-Deep Spot across LakeQuality
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Where this data comes from
22 measurements from 1 monitoring station, 2021–2025. Retrieved from the EPA Water Quality Portal on 2026-08-21.
Collected and reported by
- New Hampshire Department Of Environmental Services (BEACH)
1111330022 samples · 2021–2025
Analytical methods
- 10-115-01-1 F ~ LACHAT; Total Phosphorus- Manual persulfate digest
- CHLOROPHYLL A-B-C DETERMINATION (MODIFIED)
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