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LakeQuality

Upper Suncook Pond-Deep Spot

B
Grade B — Good
Good · #15 of 27 lakes in the county · Mesotrophic
Mesotrophic

Upper Suncook Pond-Deep Spot in Belknap County, New Hampshire has a water quality grade of B (Good). Phosphorus: 11 µg/L. Chlorophyll-a (algae): 3.8 µg/L.

Type
Mesotrophic

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Upper Suncook Pond-Deep Spot is a mesotrophic lake in Belknap County, New Hampshire. Water quality is graded B based on 1 sampling years through 2025. Compared to the 26 other monitored lakes in Belknap County, Upper Suncook Pond-Deep Spot ranks #15 for water quality.

Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2025-07-14. Grade methodology: LakeGrade methodology.

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Swimming Safety

Grade only

Low algae

Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.

Good for swimming, clear water with low algae levels

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Water Quality Grade: B (Good)

No clarity data. Phosphorus level: 11 µg/L. Chlorophyll-a: 3.8 µg/L. Trophic State Index: 41.

MetricValueGrade
Water Clarity (Secchi Depth)No recent samples
Phosphorus11 µg/LGood
Chlorophyll-a (Algae)3.8 µg/LNot graded
Trophic State Index (TSI)41Mesotrophic

Moderate nutrients, good water quality

Where to stay near Upper Suncook Pond-Deep Spot

Compare lakeside cabins, hotels, and vacation rentals near Upper Suncook Pond-Deep Spot in Belknap County, New Hampshire — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water.

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Fishing Upper Suncook Pond-Deep Spot

EPA Impairment Status

Upper Suncook 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

MercuryNuisance exotic speciespH / acidity

A Total Maximum Daily Load (TMDL) plan has been approved.

Source: EPA ATTAINS assessment unit NHLAK700060402-10-02 · Official waterbody report · Matched by proximity (0.27 km)

County Ranking

Ranked #15 of 27 lakes in Belknap County

Nearby Lakes in Belknap County

Frequently asked questions about Upper Suncook Pond-Deep Spot

Where is Upper Suncook Pond-Deep Spot?

Upper Suncook Pond-Deep Spot is a lake in Belknap County, New Hampshire. LakeQuality grades it B for nutrients and algae. The letter is not a swimming clearance.

What is the water quality grade for Upper Suncook Pond-Deep Spot?

Upper Suncook Pond-Deep Spot in Belknap County, New Hampshire has a water quality grade of B (Good). Phosphorus: 11 µg/L. Chlorophyll-a (algae): 3.8 µg/L.

Is Upper Suncook Pond-Deep Spot safe to swim in?

Good for swimming, clear water with low algae levels. Upper Suncook Pond-Deep Spot has a water quality grade of B (Good). Algae concentration (chlorophyll-a) is 3.8 µg/L. Always check local health department advisories before swimming.

Where this data comes from

19 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)1111330019 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)

Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.

Other records on this page

Impairment status from EPA ATTAINS 303(d) database