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Mattoon Lake and Sara Lake both received the same overall water quality grade of F (Algae-prone). Both are in Illinois.

Reviewed by LakeQuality Editorial Team · Updated

Both Mattoon Lake and Sara Lake sit in Illinois. A same-state comparison strips out the state-level water-quality regime as a variable: any grade differences here are about the lakes themselves, not the agencies grading them. These two are within a letter of each other on the rubric — Mattoon Lake (F) versus Sara Lake (F). The deciding factors for a recreational visitor are likely physical (depth, access, fish species) rather than water-quality differences.

With grades this close, the choice between the two lakes turns on non-water-quality factors: depth, fish species, public access, distance from home. The per-lake pages below cover all of those.

F

Mattoon Lake

Cumberland County, Illinois

Very murky, less than 1.3 ft of visibility.

F

Sara Lake

Effingham County, Illinois

Very murky, less than 2.2 ft of visibility.

Side-by-Side Metrics

MetricMattoon LakeSara Lake
Overall GradeF (Algae-prone)F (Algae-prone)
Water Clarity1.3 ft2.2 ft Better
Phosphorus294 µg/L59.5 µg/L Better
Chlorophyll-a (Algae)87.1 µg/L33.9 µg/L Better
Maximum Depth--
Surface Area980 acres586 acres
Public AccessYesYes
Fish Species00
Trophic Statehypereutrophichypereutrophic

A green ✓ marks the better value for that metric (lower phosphorus / chlorophyll = cleaner; higher Secchi / depth / species count = better). Surface area and trophic state carry no tick — a bigger lake is not a better lake.

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Compare Mattoon Lake or Sara Lake against a different lake.

Verdict

Both lakes earn the same Grade F. The tiebreakers come down to clarity (Mattoon Lake: 1.3 ft, Sara Lake: 2.2 ft) and what you want from the lake. Mattoon Lake matches its peer on species count.

Source: EPA National Aquatic Resource Surveys, 2026.