Comus Lake
Comus Lake in Walworth County, Wisconsin has a water quality grade of D (Nutrient-rich). Water clarity: 1.5 ft visibility. Phosphorus: 193 µg/L. Maximum depth: 6 ft. Surface area: 131 acres.
Wisconsin DNR lists Panfish as present on Comus Lake. DNR survey details →
- Clarity
- 1.5 ft
- Max depth
- 6 ft
- Area
- 131 acres
- Type
- Hypereutrophic
- Trend
- ↓ Declining
- Public access
- Yes
Grade D measures nutrients and algae, not whether this is a good place for a cabin trip. Cabins and rentals near Comus Lake →
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Comus Lake is a 131-acre highly nutrient-loaded hypereutrophic lake in Walworth County, Wisconsin with a maximum depth of 6 feet. Water quality is graded D based on 1 sampling years through 2021. Overall water quality is declining over recent sampling years. The lake supports 3 documented fish species including Panfish, Largemouth Bass, and Northern Pike. Public access is available with 1 public boat landing. Compared to the 18 other monitored lakes in Walworth County, Comus Lake ranks #17 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2021-08-24. Grade methodology: LakeQuality methodology.
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Swimming Safety
Grade onlyLimited 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.
Nutrients and algae run higher than average — check local advisories before swimming, and skip the water if you see scum
Water Quality Grade: D (Nutrient-rich)
Very murky, less than 1.5 ft of visibility. Phosphorus level: 193 µg/L. Trophic State Index: 76.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 1.5 ft | Not graded |
| Phosphorus | 193 µg/L | Poor |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 76 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Where to stay near Comus Lake
Compare lakeside cabins, hotels, and vacation rentals near Comus Lake in Walworth County, Wisconsin — 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 Comus Lake are listed below.
Top-rated places to stay near Comus Lake
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Planning a whole trip? See where to stay at Wisconsin’s top lakes →
Wisconsin DNR lists Panfish as present on Comus Lake.
A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades Comus Lake D from EPA Water Quality Portal chemistry, and the water-quality trend over 2 years of monitoring is declining. Catch rate is not a swim clearance and is not a weekly bite report.
WI DNR Lake Profile
Authoritative data from the Wisconsin DNR LakePages. 1 station on file (most recent sample 2023).
Fish Species (DNR-rated)
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 6 ft |
| Surface Area | 131 acres |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Comus LakePublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Comus Lake
Water Quality Trend: ↓ Declining
Based on 2 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | 0 m/yr | 2 |
| Phosphorus | ↓ Declining | +113 µg/L/yr | 2 |
Reservoir Info (USACE NID)
Comus Lake is a man-made reservoir impounded by the Delavan (completed 1947), built primarily for recreation on the TURTLE CREEK; gravity-type dam, 13 ft tall and 100 ft long.
- Surface area
- 164 ac
- Normal storage
- 606 ac-ft
- Max storage
- 850 ac-ft
- Drainage area
- 67 sq mi
- Hazard class
- Low
- Owner
- City Of Delavan
Source: USACE National Inventory of Dams, NID ID WI00321 · Operator website
EPA Impairment Status
Comus Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit WI10001424 · Official waterbody report
Regulated Pollution Sources Nearby
3 EPA-permitted facilities operate within about 5 miles of Comus Lake under Clean Water Act (NPDES) discharge permits, including 1 classified by the EPA as major discharger. 1 facility has a reported Clean Water Act violation in the past three years.
- Walworth County MetroDelavan · 1.1 mi away · NPDES WI0031461MajorRecent violation
- Pentair Flow Technologies LlcDelavan · 0.7 mi away · NPDES WI0055816
- Walter & Son Waste HaulingDarien · 4.9 mi away · NPDES WI0064653
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 #17 of 19 lakes in Walworth County
Nearby Lakes With Higher Grades
Comus Lake holds Grade D. 3 nearby lakes hold higher nutrient-and-algae grades — useful for a swim day, not a reason to skip lodging here.
Nearby Lakes in Walworth County
Frequently asked questions about Comus Lake
Where is Comus Lake?
- Comus Lake is a lake in Walworth County, Wisconsin. LakeQuality grades it D for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Comus Lake?
- Comus Lake in Walworth County, Wisconsin has a water quality grade of D (Nutrient-rich). Water clarity: 1.5 ft visibility. Phosphorus: 193 µg/L. Maximum depth: 6 ft. Surface area: 131 acres.
Is Comus Lake safe to swim in?
- Nutrients and algae run higher than average — check local advisories before swimming, and skip the water if you see scum. Comus Lake has a water quality grade of D (Nutrient-rich). Always check local health department advisories before swimming.
How deep is Comus Lake?
- Comus Lake has a maximum depth of 6 feet. The lake covers 131 acres.
What fish are in Comus Lake?
- Fish species found in Comus Lake include Panfish, Largemouth Bass, Northern Pike. Comus Lake is located in Walworth County, Wisconsin.
What did the DNR fisheries survey find at Comus Lake?
- Wisconsin DNR lists Panfish as present on Comus Lake. A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades Comus Lake D from EPA Water Quality Portal chemistry, and the water-quality trend over 2 years of monitoring is declining. Catch rate is not a swim clearance and is not a weekly bite report.
Are there boat ramps on Comus Lake?
- Comus Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Comus Lake. Public access is listed as yes.
Explore Comus Lake across LakeQuality
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Where this data comes from
22 measurements from 1 monitoring station, 2020–2021. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX22 samples · 2020–2021
Analytical methods
- Phosphorus by Colorimetry
Monitoring station identifiers (1)
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)
Lake size & watershed from HydroLAKES (HydroSHEDS)
Fish and recreation data from Wisconsin DNR Lakes
Named boat-access points from the USGS National Boat Ramps inventory