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LakeQuality

Best Swimming Lakes in Wisconsin

Lake Capri (St. Francois County) ranks #1 for swimming in Wisconsin — grade A water with low algae and public access. Below: the top 25 lakes in Wisconsinthat pass our swim-safety filter (grade A/B, chlorophyll-a below 10 µg/L).

Best-for-swimming on LakeGrade weights water clarity heavily: a swimmer cares whether they can see their feet, whether the water looks inviting on a 90-degree July day, and whether there is a real harmful-algal-bloom risk. The top Missouri swimming lake on current data is Lake Capri (A).

The swimming-best list filters more aggressively on chlorophyll-a than the cleanest list — even very clear lakes can have harmful-algal-bloom risk under specific conditions, so the swimming ranking is more conservative on that front.

RankLakeCountyGradeClarityAlgaePhosphorusArea
1Lake CapriSt. FrancoisA16.3 ft0.9 µg/L5.7 µg/L112 acres
2Lake Wauwanoka Nr. DamJeffersonA12.9 ft1.7 µg/L8 µg/L86 acres
3Lake Marseilles-Terre du Lac LakesSt. FrancoisA14.1 ft2.4 µg/L7.4 µg/L56 acres
4Lake Shayne-Terre du Lac LakesWashingtonA11.1 ft1.2 µg/L5 µg/L51 acres
5Timberline LakesSt. FrancoisA14.3 ft1.6 µg/L5.5 µg/L42 acres
6Alpine LakeWarrenA12.6 ft1.5 µg/L7 µg/L325 acres
7Lake Taneycomo Ab. Bee Cr. ArmTaneyA13.3 ft1.1 µg/L13 µg/L-
8Lake Taneycomo Nr. Roark Cr.TaneyA12.6 ft0.9 µg/L14.5 µg/L-
9Council Bluff LakeIronA13.1 ft1.3 µg/L5.3 µg/L-
10Mccormack LakeOregonA11.7 ft3 µg/L6 µg/L10 acres
11Fourche Creek LakeRipleyA13.6 ft1.3 µg/L9 µg/L49 acres
12Goose Creek LakeSte. GenevieveA9.9 ft2 µg/L9.5 µg/L379 acres
13Oasis Ranch LakeAudrainA14.1 ft0.9 µg/L8 µg/L-
14Port Perry LakePerryA12 ft2.1 µg/L8.3 µg/L187 acres
15Oasis Ranch Upper LakeAudrainA14.4 ft1.8 µg/L12 µg/L-
16Lake Taneycomo @ Shepherd of the Hills FhTaneyA1.5 µg/L21.5 µg/L-
17Cattails 2 LakeJeffersonA0.8 µg/L24 µg/L4 acres
18Lake Taneycomo @ Rockaway BeachTaneyB8.7 ft1.1 µg/L13.5 µg/L-
19Fox Valley LakeClarkB8.5 ft3.6 µg/L16.5 µg/L96 acres
20Fellows LakeGreeneB7.2 ft3.4 µg/L12 µg/L812 acres
21Lake KonstanzWarrenB7.7 ft1.6 µg/L7 µg/L19 acres
22Table Rock Lk. Into Main Channel From Dam LakeStoneB7.2 ft4.5 µg/L8 µg/L43.1K acres
23Table Rock L. Ab. Carter Br. LakeBarryB6.8 ft4.3 µg/L8.5 µg/L-
24Lake TaneycomoTaneyB8.9 ft1.2 µg/L14.5 µg/L-
25Stockton Lake by DamCedarB7.9 ft4.7 µg/L11 µg/L24.9K acres

Frequently Asked Questions

What is the best lake to swim in Wisconsin?

Lake Capri in St. Francois County ranks #1 for swimming-safety in our 2026 Wisconsin dataset, combining grade-A water clarity with low algae and public access. The full top 25 above ranks the swim-safest lakes statewide.

How do you know if a lake is safe to swim in Wisconsin?

Three signals: (1) water clarity — Secchi depth above 6 feet is a strong sign of low suspended sediment and pathogens; (2) chlorophyll-a below 10 µg/L means low risk of harmful algae bloom; (3) a current grade of A or B from year-round sampling. Wisconsin DNR and county health departments post seasonal advisories — always check before you swim, especially in late summer when blue-green algae bloom risk peaks.

Are lakes in Wisconsin safe to swim in?

Most monitored Wisconsin lakes are safe to swim in under normal conditions, but water quality varies widely. The lakes ranked above are filtered to grade A and B with chlorophyll-a below 10 µg/L — meaning they consistently test cleaner and have lower algae bloom risk than the state average. Always check posted advisories before swimming and avoid water after heavy rain (bacterial contamination spikes from runoff).

What lakes have algae blooms in Wisconsin?

Algae blooms (especially blue-green / cyanobacteria) are most common in shallow, warm, nutrient-rich (eutrophic) lakes during late summer. Lakes with high phosphorus and chlorophyll-a measurements are at higher risk. The lakes on this page are filtered to exclude high-algae lakes. For the opposite list, see our most-polluted-lakes trend page.

When is it safe to swim in lakes in Wisconsin?

Wisconsin lakes are typically safest to swim in late spring through early summer (May–July), when water is cool and algae bloom risk is lowest. Risk rises in late summer and early fall (August–September) when warm water and accumulated nutrients drive cyanobacteria blooms. Always avoid swimming after heavy rainfall (bacterial spikes from runoff) and check current state DNR advisories the day you go.

What's the cleanest lake in Wisconsin?

The single cleanest lake by combined water-quality score is featured on the Wisconsin cleanest-lakes page. The lakes here are filtered specifically for swimming safety — same A/B grade requirement, plus low chlorophyll-a (active algae filter). For the broader cleanliness ranking, see /best/cleanest/wi.

Our swimming-safety filter

We don't just rank by overall grade. Lakes here have to pass three filters:

  • Grade A or B overall water quality (top 40% statewide)
  • Chlorophyll-a below 10 µg/L — actively low algae density, low risk of harmful blue-green blooms
  • Multi-year sampling data — excludes lakes with limited sampling history (data confidence)

The ranking within the filter is by combined water-quality score (Secchi clarity + phosphorus + chlorophyll-a). Always check current Wisconsin DNR advisories before swimming.

Source: EPA National Aquatic Resource Surveys, 2026.