What is the water quality grade for Cox Lake?

Cox Lake in Calhoun County, Texas received a water quality grade of D (Poor). Water clarity: 0.7 ft visibility. Phosphorus: 303 µg/L. Chlorophyll-a (algae): 15.8 µg/L.

Is Cox Lake safe to swim in?

Swimming not recommended, poor water quality with high algae risk. Cox Lake has an overall water quality grade of D. Algae concentration (chlorophyll-a) is 15.8 µg/L. Always check local health department advisories before swimming.

Calhoun County, Texas

Cox Lake

Grade DPoor · 0.7 ft clarity

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Hypereutrophic

Cox Lake is a highly nutrient-loaded hypereutrophic lake in Calhoun County, Texas. Water quality is graded D based on 2 sampling years through 2025.

Source: EPA Water Quality Portal sampling records, Texas DNR, last sampled 2025-11-20. Grade methodology: LakeGrade methodology.

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Swimming Safety

Swimming not recommended, poor water quality with high algae risk

Water Quality Grade: D, Poor

Very murky, less than 0.7 ft of visibility. Phosphorus level: 303 µg/L. Chlorophyll-a: 15.8 µg/L. Trophic State Index: 76.

Metric	Value	Grade
Water Clarity (Secchi Depth)	0.7 ft	F
Phosphorus	303 µg/L	F
Chlorophyll-a (Algae)	15.8 µg/L	C
Trophic State Index (TSI)	76	Hypereutrophic

Very high nutrients, dense algae, poor clarity

Where to stay near Cox Lake

Compare lakeside cabins, hotels, and vacation rentals near Cox Lake in Calhoun County, Texas — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water.

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