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LakeQuality

The single cleanest lake in North Carolina is Lake Waccamaw, with the highest combined water quality score in our 2026 dataset (grade A). Cleanliness is measured by Secchi depth (clarity), total phosphorus, and chlorophyll-a — all sourced from EPA Water Quality Portal and state agency sampling. The full top 25 ranked list appears below.

Ranking the cleanest North Carolina lakes means picking the basins with the strongest nutrient-and-algae letters, then the clearer water among lakes that share a letter. Lake Waccamaw leads the list with a grade of A, with Merchants Millpond close behind.

The top of the cleanest-lakes list is dominated by deep, glacial, cold-water basins — the same basins that produce the A-grade bracket overall. The pattern is not coincidence: depth and watershed land-use are the dominant inputs to water-clarity and nutrient-loading both.

RankLakeCountyGradeClarityPhosphorusChlorophyll-aArea
1Lake WaccamawColumbusA30 µg/L3.6 µg/L-
2Merchants MillpondGatesB1.6 ft270 µg/L8.2 µg/L760 acres
3Catawba Riv LakeMecklenburgC6.6 ft20 µg/L2.3 µg/L-
4Belews LakeStokesC11.6 ft30 µg/L3.5 µg/L3,863 acres
5Lake Ben JohnsonOrangeC3.3 ft50 µg/L6.5 µg/L-
6Corporation LakeOrangeC2.2 ft50 µg/L11 µg/L5 acres
7Phelps LakeWashingtonC3.6 ft50 µg/L6.2 µg/L-
8West Fk Eno R ReservoirOrangeD3.8 ft35.5 µg/L14.9 µg/L272 acres
9Cane Creek ReservoirOrangeD3.6 ft30 µg/L19.5 µg/L-
10B Everett Jordan LakeChathamD1.8 ft117 µg/L22.9 µg/L13,940 acres
11Catawba Creek LakeGastonD3.6 ft35 µg/L18.5 µg/L-
12S Fork Catawba Riv LakeGastonD3.9 ft40 µg/L13 µg/L-
13Kerr Scott ReservoirWilkesD4.9 ft30 µg/L17 µg/L-
14Farmer LakeCaswellD2.1 ft30 µg/L27 µg/L390 acres
15Wiggins Mill ReservoirWilsonD2.6 ft60 µg/L29 µg/L-
16Lake ButnerGranvilleD5.4 ft40 µg/L11 µg/L340 acres
17Kings Mountain ReservoirClevelandD6.9 ft50 µg/L11 µg/L0 acres
18Lake AdgerPolkD3.9 ft50 µg/L7.2 µg/L438 acres
19Lake JohnsonWakeD3 ft40 µg/L23 µg/L148 acres
20West Fork Eno River ReservoirOrangeD3.8 ft50 µg/L30 µg/L-
21Lake RaleighWakeD2.5 ft45 µg/L29.5 µg/L88 acres
22Toisnot ReservoirWilsonD2.3 ft90 µg/L18 µg/L-
23Back Creek LakeRandolphD40 µg/L27 µg/L236 acres
24University LakeOrangeF2.3 ft40 µg/L33.3 µg/L213 acres
25B E Jordan LakeChathamF2.6 ft40.5 µg/L35.5 µg/L-

Get updates when North Carolina's cleanest-lake list changes

New nutrient and algae samples can move a lake up or down this ranking. Unsubscribe anytime.

Clearest lakes in North Carolina by water clarity

“Clearest” ranks by Secchi depth — how far you can see into the water — which can differ from the combined cleanliness score above. The clearest water in North Carolina is Wolf Creek Reservoir at 19.7 ft of Secchi visibility.

  1. 1. Wolf Creek Reservoir19.7 ft, Jackson County
  2. 2. Calderwood Lake16.4 ft, Graham County
  3. 3. Lake Cheoah14.6 ft, Graham County
  4. 4. Santeetlah Lake14.3 ft, Graham County
  5. 5. Fontana Lake14.1 ft, Graham County
See the full clearest-lakes ranking for North Carolina

Frequently Asked Questions

What is the cleanest lake in North Carolina?

Lake Waccamaw has the highest water quality score in our 2026 North Carolina dataset (grade A). Lakes are graded A to F on nutrients and algae — total phosphorus, total nitrogen, chlorophyll-a, and turbidity — measured against the EPA National Lakes Assessment 2022 condition classes for that lake's own ecoregion, so a lake is judged against the lakes it would naturally resemble. Cleanliness here means a low nutrient load and little algae, measured directly from EPA and state DNR samples; where two lakes tie on the letter, the deeper Secchi reading ranks first.

What is the most polluted lake in North Carolina?

Among monitored North Carolina lakes, Lake Reese ranks among the most polluted by combined phosphorus and chlorophyll-a load. See our full ranking on the most-polluted-lakes trend page for state-by-state details.

Where in North Carolina has the cleanest water?

North Carolina's clearest waters are concentrated in deeper, lower-nutrient glacial basins with forested or low-agriculture watersheds. Among the current top-ranked lakes above, counties like Orange, Chatham, and Gaston produce the highest-scoring lakes.

What is the clearest lake in North Carolina?

Wolf Creek Reservoir is the clearest lake in North Carolina by water clarity, with a Secchi depth of 19.7 feet — the deepest transparency in our 2026 dataset. "Clearest" ranks by Secchi depth (how far you can see into the water) specifically, while "cleanest" combines clarity with phosphorus and chlorophyll-a. See our full clearest-lakes ranking for North Carolina for the top 25 by Secchi clarity.

Are these lakes safe to swim in?

Not on the letter alone. An A or B is a nutrients-and-algae classification, not a swimming clearance — it does not measure E. coli, cyanotoxins, or a posted beach closure, and a lake with low chlorophyll-a can still bloom. Always check current posted advisories before swimming: water quality changes seasonally, especially in late summer when blue-green algae bloom risk peaks.

How are these grades calculated?

The letter is nutrients and algae — phosphorus, nitrogen, chlorophyll-a, and turbidity — scored against EPA National Lakes Assessment 2022 condition classes for that lake’s ecoregion, not a North Carolina-only 0–100 average and not an equal-weight mean with Secchi. Water clarity is shown; it is not scored. Lakes without enough recent sampling are UNRATED. Our methodology page has the full rubric.

What are the top 5 cleanest lakes in the US?

There is no single national ranking of cleanest lakes — each state agency uses different metrics. Crater Lake (Oregon) is widely cited as the clearest US lake, with Secchi depths over 30 m. Lake Tahoe and Lake Superior are also top-tier nationally. Within North Carolina, the 25 lakes ranked above are the graded lakes with the highest letters in our 2026 dataset.

How we rank cleanest lakes

Cleanliness here means three things working together:

  • Secchi clarity — how deep you can see into the water (in feet). Greater depth = clearer water = lower suspended sediment and algae.
  • Total phosphorus — the nutrient that fuels algae. Lower phosphorus levels mean less algae growth potential.
  • Chlorophyll-a — the green pigment in algae. Direct measurement of how much algae is currently in the water.

Each signal is normalized against North Carolina state norms and combined into a single 0–100 score. The lakes above are sorted by that combined score.Full methodology →

Where to stay near North Carolina's cleanest lakes

Compare cabins, resorts, and rentals near the clearest, lowest-algae lakes in North Carolina — live availability and prices for your trip.

Top-rated places to stay near North Carolina's cleanest lakes

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Source: EPA National Aquatic Resource Surveys, 2026.