What is the water quality grade for Windmill Lake?

Windmill Lake in Taylor County, Wisconsin received a water quality grade of F (Very Poor). Water clarity: 2.5 ft visibility. Chlorophyll-a (algae): 33.9 µg/L. Surface area: 24.5 acres.

Is Windmill Lake safe to swim in?

Avoid swimming, very poor water quality, potential algae toxins. Windmill Lake has an overall water quality grade of F. Algae concentration (chlorophyll-a) is 33.9 µg/L. Always check local health department advisories before swimming.

Windmill Lake

Taylor County, WisconsinEutrophic

Windmill Lake is a 25-acre productive, nutrient-rich eutrophic lake in Taylor County, IA. Water quality is graded F based on 2 sampling years through 2024. Compared to the 3 other monitored lakes in Taylor County, Windmill Lake ranks #4 for water quality.

Source: EPA Water Quality Portal sampling records, local state DNR records, last sampled 2024-10-01. Grade methodology: LakeGrade methodology.

Swimming Safety

Avoid swimming, very poor water quality, potential algae toxins

Water Quality Grade: F, Very Poor

Very murky, less than 2.5 ft of visibility. Chlorophyll-a: 33.9 µg/L. Trophic State Index: 65.

Metric	Value	Grade
Water Clarity (Secchi Depth)	2.5 ft	F
Phosphorus	No data
Chlorophyll-a (Algae)	33.9 µg/L	F
Trophic State Index (TSI)	65	Eutrophic

High nutrients, frequent algae, reduced clarity

Lake Details

Characteristic	Value
Surface Area	24.5 acres

Location

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County Ranking

Ranked #4 of 4 lakes in Taylor County

Cleaner Lakes Within 30 Miles

Windmill Lake holds Grade F. One nearby lake has a higher grade.

D
Binder Lake
Adams County · 19.8 mi · Higher grade (F → D)

See full comparison →

Nearby Lakes in Taylor County

Lake of Three Fires Max Depth

More Wisconsin Lake Rankings

Cleanest lakes in Wisconsin

Top 25 by overall water quality score

Best swimming lakes in Wisconsin

Grade A/B + low algae filter

Family fishing lakes in Wisconsin

Panfish-rich, public access

All Wisconsin lakes

Full state directory

Other Grade F Lakes in Wisconsin

Big Creek Lake

Polk County · Clarity: 2.6 ft

Arrowhead Lake

Pottawattamie County · Clarity: 1.8 ft

White Oak Lake

Mahaska County · Clarity: 1.4 ft

Crystal Lake Max Depth

Hancock County · Clarity: 1.6 ft

Hannen Lake

Benton County · Clarity: 1.2 ft

Briggs Woods Lake

Hamilton County · Clarity: 1.5 ft

Eutrophic Lakes in Wisconsin

Big Creek Lake Storm Lake Max Depth Lost Island Lake Nodaway Lake

Reservoir Info (USACE NID)

Windmill Lake is a man-made reservoir impounded by the Windmill Lake Dam (completed 1969), built primarily for recreation on the TR-WEST BRANCH 102 RIVER; earth-type dam, 35 ft tall and 900 ft long.

Surface area: 24.5 ac
Normal storage: 66 ac-ft
Max storage: 247 ac-ft
Drainage area: 0.84 sq mi
Hazard class: Low
Owner: Taylor County Conservation Board

Source: USACE National Inventory of Dams, NID ID IA01053 · Operator website

EPA Impairment Status

Windmill Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).

Causes of impairment

Turbidity

A Total Maximum Daily Load (TMDL) plan has been approved.

Source: EPA ATTAINS assessment unit IA 05-PLA-1482 · Official waterbody report

Data Sources

Water quality data from the EPA Water Quality Portal

Impairment status from EPA ATTAINS 303(d) database

Grading methodology based on Metropolitan Council standards

Most recent sample: 2024-10-01

Monitoring stations: 1