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LakeQuality

Nashville City Lake

Washington County, Illinois52 acresView mapDirections

F
Algae-prone

Nutrients and algae run well above the regional average.

Water temp
~84°F
Typical for Aug · EPA WQP
Clarity
1.3 ft
Secchi · sampled 2022
Level
No reading
No gauge
Trend
No reading
Not enough history
  • Hypereutrophic
  • Impaired · Mercury
  • #1 of 1 in the county
  • Limited data

Nashville City Lake in Washington County, Illinois has a water quality grade of F (Algae-prone). Water clarity: 1.3 ft visibility. Phosphorus: 606 µg/L. Chlorophyll-a (algae): 89.3 µg/L. Surface area: 52 acres.

Clarity
1.3 ft
Typical in August
84°F
Area
52 acres
Type
Hypereutrophic
Phosphorus
606 µg/L
Chlorophyll-a
89.3 µg/L
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Stays via Stay22

Stays near Nashville City Lake

Compare lakeside cabins, hotels, and vacation rentals near Nashville City Lake in Washington County, Illinois — 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. The water-quality grade measures nutrients and algae, not lodging — cabins and rentals around Nashville City Lake are listed below.

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

Source: EPA Water Quality Portal sampling records, Illinois EPA, last sampled 2022-10-11. Grade methodology: LakeQuality methodology.

Swimming Safety

Grade only

Limited data

Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.

The F is nutrients and algae, not a swimming clearance. Nashville City Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, nutrients (phosphorus, nitrogen), pesticides. Check local advisories before you swim.

Compare the safest swimming lakes near St. Louis

Get alerts for Nashville City Lake

Water Quality Grade: F (Algae-prone)

Very murky, less than 1.3 ft of visibility. Phosphorus 606 µg/L. Chlorophyll-a 89.3 µg/L. TSI 81. The letter is not a swimming clearance.

MetricValueGrade
Water Clarity (Secchi Depth)1.3 ftNot graded
Phosphorus606 µg/LPoor
Chlorophyll-a (Algae)89.3 µg/LPoor
Trophic State Index (TSI)81Hypereutrophic

Very high nutrients, dense algae, poor clarity

Water Temperature

Nashville City Lake typically sits around 84°F at the surface in August. Summer average is about 84°F. Usually warmest in Jul (about 85°F) and coldest in Oct (about 60°F). These are typical values by month — not a live reading.

Jan
Feb
Mar
Apr
65°
May
67°
Jun
82°
Jul
85°
Aug
84°
Sep
Oct
60°
Nov
Dec

Typical surface water temperature by month, from 197 field readings (20122022) via the EPA Water Quality Portal. See the full Nashville City Lake water temperature breakdown →

Lake Details

CharacteristicValue
Surface Area52 acres

No bathymetric survey has been published for Nashville City Lake, so its depth is not documented here.

Fishing Nashville City 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

Regulated Pollution Sources Nearby

5 EPA-permitted facilities operate within about 5 miles of Nashville City Lake under Clean Water Act (NPDES) discharge permits. 3 facilities have a reported Clean Water Act violation in the past three years.

  • New Minden Stp, Village Of
    Nashville · 1.6 mi away · NPDES IL0041335
    Recent violation
  • Nashville Stp, City Of
    Nashville · 1.7 mi away · NPDES IL0027081
    Recent violation
  • Washington County Conservation Area -Stp
    Nashville · 4.4 mi away · NPDES IL0048577
    Recent violation
  • Nashville Wtp, City Of
    Nashville · 0.2 mi away · NPDES IL0069701
  • Nascote Industries, Inc.
    Nashville · 1.3 mi away · NPDES IL0068136

Facilities permitted to discharge under the Clean Water Act within ~5 miles; proximity does not by itself mean a facility affects this lake. Source: EPA ECHO (ICIS-NPDES), as of 2026-07.

County Ranking

Ranked #1 of 1 lakes in Washington County

Nearby Lakes in Washington County

Frequently asked questions about Nashville City Lake

Where is Nashville City Lake?

Nashville City Lake is a lake in Washington County, Illinois. LakeQuality grades it F for nutrients and algae. The letter is not a swimming clearance.

What is the water quality grade for Nashville City Lake?

Nashville City Lake in Washington County, Illinois has a water quality grade of F (Algae-prone). Water clarity: 1.3 ft visibility. Phosphorus: 606 µg/L. Chlorophyll-a (algae): 89.3 µg/L. Surface area: 52 acres.

Is Nashville City Lake safe to swim in?

The F is nutrients and algae, not a swimming clearance. Nashville City Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, nutrients (phosphorus, nitrogen), pesticides. Check local advisories before you swim.

What is the water temperature of Nashville City Lake?

Nashville City Lake typically sits around 84°F at the surface in August, from 197 EPA Water Quality Portal field readings (2012–2022). That is a typical value for the month, not a live reading.

Where this data comes from

48 measurements from 3 monitoring stations, 2022. Retrieved from the EPA Water Quality Portal on 2026-08-02.

Collected and reported by

  • illinois epaIL_EPA_WQX48 samples · 2022

Analytical methods

  • MEASURED IN FIELD
  • Phosphorus by Colorimetry
  • 10200 H 2 ~ Chlorophyll a-b-c Determination by spectrophotometer
Monitoring station identifiers (3)

Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.

Other records on this page

Impairment status from EPA ATTAINS 303(d) database

Regulated discharger data from EPA ECHO (ICIS-NPDES)