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The single cleanest lake in Missouri is Sherwood Lake (Warren County, MO), 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.

The "cleanest" ranking on LakeQuality starts from the A–F letter — nutrients and algae scored against EPA National Lakes Assessment 2022 ecoregion classes. Secchi clarity is shown and used only as a tiebreak, not as a graded input. The cleanest Missouri lake on the current data is Sherwood Lake (Warren County, MO) (A).

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
1Sherwood Lake (Warren County, MO)WarrenA5.9 ft14.3 µg/L4.4 µg/L145 acres
2Fox Valley LakeClarkA8.5 ft16.5 µg/L3.6 µg/L96 acres
3Bull Shoals LakeTaneyA8.1 ft10 µg/L4 µg/L-
4Lake Shayne-Terre du Lac LakesWashingtonA11.1 ft5.2 µg/L1.2 µg/L51 acres
5Lake KonstanzWarrenA7.7 ft7 µg/L1.6 µg/L19 acres
6Lake CapriSt. FrancoisA16.3 ft5.7 µg/L0.9 µg/L112 acres
7Innsbrook LakeWarrenA5.2 ft17 µg/L5 µg/L-
8Weatherby LakePlatteA6.2 ft16 µg/L5.9 µg/L186 acres
9Table Rock L. Ab. Carter Br. LakeBarryA6.8 ft8.5 µg/L4.3 µg/L-
10Council Bluff LakeIronA13.1 ft5.7 µg/L1.3 µg/L-
11Bowling Green LakePikeA5.5 ft24.6 µg/L5.1 µg/L45 acres
12Lake TaneycomoTaneyA8.9 ft15.8 µg/L1.2 µg/L-
13Lake TaneycomoTaneyA12.6 ft14.5 µg/L0.9 µg/L-
14Lake WauwanokaJeffersonA12.9 ft8 µg/L1.7 µg/L-
15Fellows LakeGreeneA7.2 ft11.8 µg/L3.4 µg/L812 acres
16Alpine LakeWarrenA12.6 ft7 µg/L1.5 µg/L325 acres
17Castlenovo LakeWarrenA6 ft16.8 µg/L2.9 µg/L10 acres
18Aspen Lake Along Southern ArmWarrenA3.8 ft20.8 µg/L5.3 µg/L146 acres
19Timberline LakesSt. FrancoisA14.3 ft5.5 µg/L1.6 µg/L42 acres
20Lincoln LakeLincolnA5.7 ft12.7 µg/L3.6 µg/L48 acres
21Lake ButeoJohnsonA5.6 ft20 µg/L4 µg/L8 acres
22Lake Taneycomo Ab. Bee Cr. ArmTaneyA13.3 ft13 µg/L1.1 µg/L-
23Brookfield LakeLinnA4.4 ft19.7 µg/L4.9 µg/L106 acres
24Rock Lake Village LakeJohnsonA4.3 ft16 µg/L4.8 µg/L27 acres
25Seetal LakeGasconadeA7.2 ft17 µg/L5.9 µg/L14 acres

Get updates when Missouri's cleanest-lake list changes

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

Clearest lakes in Missouri 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 Missouri is Lake Capri at 16.3 ft of Secchi visibility.

  1. 1. Lake Capri16.3 ft, St. Francois County
  2. 2. Oasis Ranch Upper Lake14.4 ft, Audrain County
  3. 3. Timberline Lakes14.3 ft, St. Francois County
  4. 4. Lake Marseilles-Terre du Lac Lakes14.1 ft, St. Francois County
  5. 5. Oasis Ranch Lake14.1 ft, Audrain County
See the full clearest-lakes ranking for Missouri

Frequently Asked Questions

What is the cleanest lake in Missouri?

Sherwood Lake (Warren County, MO) has the highest water quality score in our 2026 Missouri 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 Missouri?

Among monitored Missouri lakes, Blue River Parkway Lake 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 Missouri has the cleanest water?

Missouri'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 Warren, Taney, and St. Francois produce the highest-scoring lakes.

What is the clearest lake in Missouri?

Lake Capri is the clearest lake in Missouri by water clarity, with a Secchi depth of 16.3 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 Missouri 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 Missouri-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 Missouri, 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 Missouri 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 Missouri's cleanest lakes

Compare cabins, resorts, and rentals around Sherwood Lake (Warren County, MO) and the other lakes in this ranking, with live availability and prices for your trip. Each pin on the map is one of the ranked lakes above.

Top-rated places to stay near Sherwood Lake (Warren County, MO)

Prices for Sep 11–13, 4 adults. Change dates on the map below.

Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.

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Source: EPA National Aquatic Resource Surveys, 2026.