What is the water quality grade for Cool Branch Lake?

Cool Branch Lake in Franklin County, Virginia received a water quality grade of A (Excellent). Water clarity: 10.5 ft visibility. Phosphorus: 10 µg/L. Chlorophyll-a (algae): 2.1 µg/L.

Is Cool Branch Lake safe to swim in?

Excellent for swimming, crystal clear water with minimal algae. Cool Branch Lake has an overall water quality grade of A. Algae concentration (chlorophyll-a) is 2.1 µg/L. Always check local health department advisories before swimming.

Franklin County, Virginia

Cool Branch Lake

Grade AExcellent · 10.5 ft clarity

Find places to stay →

Oligotrophic

Cool Branch Lake is a cold, clear oligotrophic lake in Franklin County, Virginia. Water quality is graded A based on 2 sampling years through 2026. Compared to the 13 other monitored lakes in Franklin County, Cool Branch Lake ranks #4 for water quality.

Source: EPA Water Quality Portal sampling records, Virginia DNR, last sampled 2026-06-16. Grade methodology: LakeGrade methodology.

Watch Cool Branch Lake water quality

Subscribe for LakeQuality updates by email. No spam, unsubscribe anytime.

Swimming Safety

Excellent for swimming, crystal clear water with minimal algae

Water Quality Grade: A, Excellent

Good clarity, visible to about 10.5 ft. Phosphorus level: 10 µg/L. Chlorophyll-a: 2.1 µg/L. Trophic State Index: 39.

Metric	Value	Grade
Water Clarity (Secchi Depth)	10.5 ft	B
Phosphorus	10 µg/L	A
Chlorophyll-a (Algae)	2.1 µg/L	A
Trophic State Index (TSI)	39	Oligotrophic

Low nutrients, clear water, excellent for swimming

Where to stay near Cool Branch Lake

Compare lakeside cabins, hotels, and vacation rentals near Cool Branch Lake in Franklin County, Virginia — 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.

Top-rated places to stay near Cool Branch Lake