Belknap County Lake Quality
New Hampshire, 30 lakes, average grade B (Good)
Belknap County's 30 graded lakes fall in the moderate-density bracket for New Hampshire. The county-level average smooths over real differences — a single agricultural watershed near the southwest corner can pull the average down even if the rest of the county runs clean. With an average grade of B, Belknap County sits comfortably above the New Hampshire median.
Most of the county's monitored lakes are shallow — under 50 feet — which means wind keeps the water column mixed all summer and sediment-bound phosphorus releases back into the surface layer whenever the bottom is disturbed. Lake Winnisquam Mohawk Isl-Deep Spot (A) is the cleanest in the county.
Where to stay near Belknap County
Top-rated places to stay near Belknap County
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
Planning a trip to Belknap County?
Get lake water-quality report cards plus the best cabin & lodging deals near Belknap County — straight to your inbox. No spam, unsubscribe anytime.
Quick Answers for Belknap County
Planning a trip? Check special fishing regulations for Lake Winnisquam Mohawk Isl-Deep Spot — or check the official New Hampshire fishing regulations.
All Lakes in Belknap County
30 lakes · 24 graded, 6 not rated24 graded lakes · 6 not rated, hidden
| # | Lake | Grade | Clarity | Phosphorus | Algae | Trophic | Access |
|---|---|---|---|---|---|---|---|
| 1 | ALake Winnisquam Mohawk Isl-Deep SpotBelknap | A | No recent samples | 10.4 µg/L | 1.2 µg/L | No recent samples | Not recorded |
| 2 | ALake Winnisquam Pot Island-Deep SpotBelknap | A | No recent samples | 6.6 µg/L | 0.8 µg/L | No recent samples | Not recorded |
| 3 | BCrystal Lake-OutletBelknap | B | No recent samples | 11.6 µg/L | No recent samples | No recent samples | Not recorded |
| 4 | BHermit Lake-Deep SpotBelknap | B | No recent samples | 12.7 µg/L | 12.9 µg/L | No recent samples | Not recorded |
| 5 | BHills Pond-Deep SpotBelknap | B | No recent samples | 12.9 µg/L | 6.1 µg/L | No recent samples | Not recorded |
| 6 | BLake Waukewan-Perkins CoveBelknap | B | No recent samples | 8.1 µg/L | No recent samples | No recent samples | Not recorded |
| 7 | BLake Winnisquam-OutletBelknap | B | No recent samples | 9.8 µg/L | No recent samples | No recent samples | Not recorded |
| 8 | BLoon Pond-Deep SpotBelknap | B | No recent samples | 9.8 µg/L | 5.7 µg/L | No recent samples | Not recorded |
| 9 | BLower Suncook Pond-Deep SpotBelknap | B | No recent samples | 10.7 µg/L | 1.9 µg/L | No recent samples | Not recorded |
| 10 | BOpechee Bay-Deep Spot LakeBelknap | B | No recent samples | 8.4 µg/L | No recent samples | No recent samples | Not recorded |
| 11 | BPemigewasset Lake-OutletBelknap | B | No recent samples | 8.1 µg/L | No recent samples | No recent samples | Not recorded |
| 12 | BPemigewasset Lake-VlapBelknap | B | No recent samples | 15.4 µg/L | No recent samples | No recent samples | Not recorded |
| 13 | BSawyer Lake-Deep SpotBelknap | B | No recent samples | 9.9 µg/L | 3 µg/L | No recent samples | Not recorded |
| 14 | BUpper Suncook Pond-Deep SpotBelknap | B | No recent samples | 11 µg/L | 3.8 µg/L | No recent samples | Not recorded |
| 15 | BWicwas Lake-Deep SpotBelknap | B | No recent samples | 10.7 µg/L | 4 µg/L | No recent samples | Not recorded |
| 16 | BWicwas Lake-East CoveBelknap | B | No recent samples | 5.9 µg/L | No recent samples | No recent samples | Not recorded |
| 17 | BWicwas Lake-Marion CoveBelknap | B | No recent samples | 6.9 µg/L | No recent samples | No recent samples | Not recorded |
| 18 | BWicwas Lake-West CoveBelknap | B | No recent samples | 6.3 µg/L | No recent samples | No recent samples | Not recorded |
| 19 | CCrystal Lake-Deep SpotBelknap | C | No recent samples | 11.1 µg/L | 7 µg/L | No recent samples | Not recorded |
| 20 | CHawkins Pond-Deep SpotBelknap | C | No recent samples | 17.5 µg/L | 4.7 µg/L | No recent samples | Not recorded |
| 21 | DLake Winona-Chutes CoveBelknap | D | No recent samples | 30 µg/L | No recent samples | No recent samples | Not recorded |
| 22 | DPickerel Cove Upstream LakeBelknap | D | No recent samples | 29 µg/L | No recent samples | No recent samples | Not recorded |
| 23 | DShellcamp Pond-Deep SpotBelknap | D | No recent samples | 17.7 µg/L | 14.3 µg/L | No recent samples | Not recorded |
| 24 | DWicwas Lake-Bacteria SampleBelknap | D | No recent samples | 28.9 µg/L | No recent samples | No recent samples | Not recorded |
| NRBear Pond-Deep SpotBelknap | NR | No recent samples | 26.5 µg/L | No recent samples | No recent samples | Not recorded | |
| NRHalfmoon LakeBelknap | NR | 14.2 ft | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRLake Waukewan-Boat LaunchBelknap | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRLake Winona-North Cove EastBelknap | NR | No recent samples | 9.6 µg/L | No recent samples | No recent samples | Not recorded | |
| NROtter Pond-Deep SpotBelknap | NR | No recent samples | 13.6 µg/L | No recent samples | No recent samples | Not recorded | |
| NRPickerel Cove Downstream LakeBelknap | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded |
NR = not rated: the monitoring record does not meet the evidence bar for a grade. That is EPA Integrated Reporting Category 3 (insufficient information), not a failing grade. How grading works.
Lake Match
Which lake suits how you actually use one?
Six questions — swimming, fishing, quiet, cabins, drive time — and a shortlist of graded lakes that fit, with the water quality behind each one.
Other Counties in New Hampshire
See how Belknap County stacks up in the national county water-quality rankings, or browse the full directory of graded lakes across all 49 states and 2 Canadian provinces.
Source: EPA National Aquatic Resource Surveys, 2026.