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LakeQuality
Late afternoon sun over Slim Lake, scattering a bright path across wind-textured water
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Jackson County Lake Quality

Colorado, 22 lakes, average grade A (Excellent)

Jackson County's 22 monitored lakes fall in the moderate-density bracket for Colorado. 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. 1 of those lake carry an A–F grade. The county-level summary describes that subset, not every water body listed. The county's average grade is A — among the cleanest in Colorado. 1 lakes pull an A on their own, and almost none fall into the D or F brackets.

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 John (A) is the cleanest in the county.

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All Lakes in Jackson County

22 lakes · 1 graded, 21 not rated1 graded lake · 21 not rated, hidden

#LakeGradeClarityPhosphorusAlgaeTrophicAccess
1ALake JohnJacksonA13.8 ft18 µg/L1.6 µg/LNo recent samples✓ Public
NRSummit LakeJacksonNR12.1 ft20 µg/LNo recent samplesNo recent samplesNot recorded
NRNorth Delaney LakeJacksonNR8.2 ftNo recent samples1 µg/LNo recent samples✓ Public
NRSeven LakesJacksonNRNo recent samples10.5 µg/LNo recent samplesNo recent samplesNot recorded
NRBig Creek LakesJacksonNRNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded
NRBig Creek LakesJacksonNRNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded
NRCowdrey ReservoirJacksonNRNo recent samplesNo recent samplesNo recent samplesNo recent samples✓ Public
NRWalden ReservoirJacksonNRNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded
NREast Delaney LakeJacksonNRNo recent samplesNo recent samplesNo recent samplesNo recent samples✓ Public
NRSouth Delaney LakeJacksonNRNo recent samplesNo recent samplesNo recent samplesNo recent samples✓ Public
NRAlkali LakeJacksonNRNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded
NRBoettcher LakeJacksonNRNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded
NRAgua Fria LakeJacksonNRNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded
NRRainbow LakeJacksonNRNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded
NRRoxy Ann LakeJacksonNRNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded
NRPole Mountain LakeJacksonNRNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded
NRMac Farlane ReservoirJacksonNRNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded
NRNorth Michigan Creek ReservoirJacksonNRNo recent samplesNo recent samplesNo recent samplesNo recent samples✓ Public
NRMeadow Creek ReservoirJacksonNRNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded
NRLake RubyJacksonNRNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded
NRSeymour LakeJacksonNRNo recent samplesNo recent samplesNo recent samplesNo recent samples✓ Public
NRWest Arapaho ReservoirJacksonNRNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot recorded

NR = not rated: there is not enough recent sampling to support a letter. That is EPA Integrated Reporting Category 3 (insufficient information), not a failing grade. How grading works.

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Source: EPA National Aquatic Resource Surveys, 2026.