Updated Aug 2026
New Jersey Lake Water Quality
Water quality grades for 109 monitored lakes across 19 counties.
Across New Jersey, 109 lakes carry an active water-quality grade spread over 19 counties. The underlying measurements come from the New Jersey Department of Environmental Protection, alongside federal programs and volunteer monitoring networks. Only about 14% of New Jersey's lakes pull an A grade — the smaller, agricultural-watershed lakes that dominate the dataset tend to carry persistent nutrient loads. 43% of lakes fall in the D or F brackets.
Eutrophic conditions dominate — nutrient-loaded, productive, with algal pressure that shows up most years in late summer. These lakes tend to be shallow, agricultural-watershed, and over-warmed by the time July ends. Cape May ranks highest on average county grade (A). Cumberland sits lowest. With only 19 counties in the state, the cross-county spread is narrower than the within-county spread for most lakes.
Grade Distribution
All 109 New Jersey lakes in the index: 79 (72.5%) carry an A–F grade and 30 (27.5%) are not rated — their monitoring record does not meet the evidence bar.
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Top-Graded New Jersey Lakes
The highest water-quality grades in New Jersey — clarity, depth, and A-F grade at a glance.
Lake Map
New Jersey reports, fishing & travel
New Jersey Fishing & Recreation
Licenses, regulations, records, and where to fish across New Jersey.
Counties
All 19 New Jersey counties, ranked by average lake water quality. Compare them against every county nationwide in the county rankings, browse the full directory of graded lakes, or pick a different state.
Top 25 Cleanest Lakes
25 lakes25 graded lakes
| # | Lake | County | Grade | Clarity | Trophic | Access |
|---|---|---|---|---|---|---|
| 1 | AEast Brunswick Community Park Lake | Middlesex | A | 10.2 ft | Mesotrophic | Not recorded |
| 2 | AGreat Gorge Lake | Sussex | A | 12.3 ft | Mesotrophic | Not recorded |
| 3 | AGrenloch Lake | Gloucester | A | 4.8 ft | Mesotrophic | Not recorded |
| 4 | AHoliday City Lake | Ocean | A | No recent samples | Mesotrophic | Not recorded |
| 5 | ALake Absegami | Burlington | A | 3.3 ft | Oligotrophic | Not recorded |
| 6 | ALake Lenape | Atlantic | A | 2.7 ft | Mesotrophic | Not recorded |
| 7 | AMashipacong Pond | Sussex | A | 9.7 ft | Mesotrophic | Not recorded |
| 8 | AMill Pond | Atlantic | A | No recent samples | Mesotrophic | Not recorded |
| 9 | AMt. Misery Lake | Burlington | A | 4.4 ft | Mesotrophic | Not recorded |
| 10 | AOswego Lake | Burlington | A | 2.1 ft | Mesotrophic | Not recorded |
| 11 | APohatcong Lake | Ocean | A | 4.6 ft | Oligotrophic | Not recorded |
| 12 | ARound Valley Reservoir | Hunterdon | A | 26.9 ft | Oligotrophic | Not recorded |
| 13 | AStephen Lake | Atlantic | A | 4.1 ft | Mesotrophic | Not recorded |
| 14 | AUnl Lake | Cape May | A | 5.6 ft | Mesotrophic | Not recorded |
| 15 | AWells Mills Reservoir | Ocean | A | 4.3 ft | Oligotrophic | Not recorded |
| 16 | BBargaintown Pond | Atlantic | B | 1.1 ft | Eutrophic | Not recorded |
| 17 | BHoliday Lake | Ocean | B | 5.2 ft | Eutrophic | Not recorded |
| 18 | BLake Topanemus | Monmouth | B | 5.4 ft | Eutrophic | Not recorded |
| 19 | BLee Bros Pond | Burlington | B | 1 ft | Eutrophic | Not recorded |
| 20 | BMeadow Lakes | Mercer | B | 4.3 ft | Eutrophic | Not recorded |
| 21 | CAncora Pond | Camden | C | 3.9 ft | Eutrophic | Not recorded |
| 22 | CDuhernal Lake | Middlesex | C | 4.6 ft | Mesotrophic | Not recorded |
| 23 | CGropp Lake | Mercer | C | 3.3 ft | Eutrophic | Not recorded |
| 24 | CHammonton Lake | Atlantic | C | 5.2 ft | Eutrophic | Not recorded |
| 25 | CIndian Mills Lake | Burlington | C | 1.6 ft | Eutrophic | Not recorded |
25 Lakes Needing Attention
25 lakes25 graded lakes
| # | Lake | County | Grade | Clarity |
|---|---|---|---|---|
| 1 | FWeequahic Lake | Essex | F | 3.9 ft |
| 2 | FSylvan Lake | Monmouth | F | 1.8 ft |
| 3 | FSunset Lake | Cumberland | F | 1.5 ft |
| 4 | FSouth Shore Marina Lake | Passaic | F | No recent samples |
| 5 | FNewton Lake | Camden | F | 1.5 ft |
| 6 | FMid Lake Surface | Morris | F | No recent samples |
| 7 | FEtra Lake | Mercer | F | 3.9 ft |
| 8 | FEagle Lake | Burlington | F | 1.1 ft |
| 9 | FDelaware Lake | Warren | F | 1.6 ft |
| 10 | FCurlis Lake | Mercer | F | 2.4 ft |
| 11 | FCountry Lake | Burlington | F | 0.7 ft |
| 12 | FChapin Pond | Morris | F | 2.8 ft |
| 13 | FCarnegie Lake | Mercer | F | 2.1 ft |
| 14 | FBy the Browns Point State Park Lake | Passaic | F | No recent samples |
| 15 | FBy Storm Island Lake | Passaic | F | No recent samples |
| 16 | FBy Fox Island Lake | Passaic | F | No recent samples |
| 17 | DWinnebago Lake | Morris | D | 3.8 ft |
| 18 | DWatchu Pond | Sussex | D | 5.6 ft |
| 19 | DVerona Lake | Essex | D | 2.6 ft |
| 20 | DUnl Lake | Sussex | D | 3.3 ft |
| 21 | DTurtle Cove Lake | Sussex | D | 4.6 ft |
| 22 | DThree-Finger Cove Lake | Sussex | D | 3.9 ft |
| 23 | DTamarack Cove Lake | Sussex | D | 5.2 ft |
| 24 | DSouth End Lake | Sussex | D | 4.4 ft |
| 25 | DSmithville Dock Lake | Burlington | D | 1.6 ft |
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.
Source: EPA National Aquatic Resource Surveys and the EPA Water Quality Portal.