What is the water quality grade for Nashville City Lake?

Nashville City Lake in Washington County, Wisconsin received a water quality grade of F (Very Poor). Water clarity: 1.3 ft visibility. Phosphorus: 517 µg/L. Surface area: 52 acres.

Is Nashville City Lake safe to swim in?

Avoid swimming, very poor water quality, potential algae toxins. Nashville City Lake has an overall water quality grade of F. Always check local health department advisories before swimming.

Nashville City Lake

Washington County, WisconsinHypereutrophic

Nashville City Lake is a 52-acre highly nutrient-loaded hypereutrophic lake in Washington County, IL. Water quality is graded F based on 2 sampling years through 2022.

Source: EPA Water Quality Portal sampling records, local state DNR records, last sampled 2022-10-11. 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 1.3 ft of visibility. Phosphorus level: 517 µg/L. Trophic State Index: 84.

Metric	Value	Grade
Water Clarity (Secchi Depth)	1.3 ft	F
Phosphorus	517 µg/L	F
Chlorophyll-a (Algae)	No data
Trophic State Index (TSI)	84	Hypereutrophic

Very high nutrients, dense algae, poor clarity

Lake Details

Characteristic	Value
Surface Area	52 acres

Location

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County Ranking

Ranked #1 of 1 lakes in Washington County

Cleaner Lakes Within 30 Miles

Nashville City Lake holds Grade F. 4 nearby lakes hold higher grades.

See full comparison →

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Other Grade F Lakes in Wisconsin

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Cook County · Clarity: 2 ft

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Cook County · Clarity: 1.5 ft

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Cook County · Clarity: 2.5 ft

Bull Frog Lake

Cook County · Clarity: 3 ft

Belly Deep Slough Lake

Cook County · Clarity: 0.7 ft

Sauk Lake

Cook County · Clarity: 1 ft

Hypereutrophic Lakes in Wisconsin

Bode Lake North Belly Deep Slough Lake Sauk Lake Washington Park Lagoon Lake

Reservoir Info (USACE NID)

Nashville City Lake is a man-made reservoir impounded by the Nashville City Reservoir Dam (completed 1935), built primarily for recreation on the TRIB NASHVILLE CREEK; earth-type dam, 26 ft tall and 740 ft long.

Surface area: 52 ac
Normal storage: 400 ac-ft
Max storage: 701 ac-ft
Drainage area: 1.4 sq mi
Hazard class: High
Owner: CITY OF NASHVILLE

All listed purposes: Recreation;Water Supply.

Source: USACE National Inventory of Dams, NID ID IL00138 · Operator website

EPA Impairment Status

Nashville City Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).

Causes of impairment

MercuryNutrients (phosphorus, nitrogen)Pesticides

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

Source: EPA ATTAINS assessment unit IL_ROO · 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: 2022-10-11

Monitoring stations: 3