Rock Lake
Rock Lake in Kenosha County, Wisconsin has a water quality grade of B (Good). Water clarity: 10 ft visibility. Phosphorus: 15.9 µg/L. Maximum depth: 33 ft. Surface area: 44 acres.
- Clarity
- 10 ft
- Typical in August
- 81°F
- Max depth
- 33 ft
- Area
- 44 acres
- Type
- Mesotrophic
- Trend
- ↓ Declining
- Public access
- Yes
Next lake in Kenosha County
Rock Lake is a 44-acre mesotrophic lake in Kenosha County, Wisconsin with a maximum depth of 33 feet. Water quality is graded B based on 1 sampling years through 2026. Overall water quality is declining over recent sampling years. The lake supports 3 documented fish species including Panfish, Largemouth Bass, and Trout. Public access is available with 1 public boat landing. Compared to the 7 other monitored lakes in Kenosha County, Rock Lake ranks #4 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-06-23. Grade methodology: LakeGrade 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.
Good for swimming, clear water with low algae levels
Water Quality Grade: B (Good)
Good clarity, visible to about 10 ft. Phosphorus level: 15.9 µg/L. Trophic State Index: 44.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 10 ft | Not graded |
| Phosphorus | 15.9 µg/L | Good |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 44 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Rock Lake
Compare lakeside cabins, hotels, and vacation rentals near Rock Lake in Kenosha 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.
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Water Temperature
Rock Lake typically sits around 81°F at the surface in August. Summer average is about 81°F. Usually warmest in Jul (about 81°F) and coldest in May (about 69°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 12 field readings (2024–2025) via the EPA Water Quality Portal. See the full Rock Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 33 ft |
| Surface Area | 44 acres |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- 113th StreetPublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Rock Lake
Invasive & Introduced Species
Red chips are ecologically harmful invasive species. Gray chips are stocked or introduced fish that aren't a current ecological concern.
WI DNR Lake Profile
Authoritative data from the Wisconsin DNR LakePages. Monitored by volunteers since 2018. 1 station on file (most recent sample 2025).
Fish Species (DNR-rated)
Water Quality Trend: ↓ Declining
Based on 7 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | +0.004 m/yr | 7 |
| Phosphorus | ↓ Declining | +0.4 µg/L/yr | 3 |
Reservoir Info (USACE NID)
Rock Lake is a man-made reservoir impounded by the Rock Lake (completed 1929), built primarily for recreation on the OUTLET OF ROCK LAKE; gravity-type dam, 8 ft tall and 100 ft long.
- Surface area
- 44 ac
- Normal storage
- 300 ac-ft
- Max storage
- 350 ac-ft
- Drainage area
- 1 sq mi
- Hazard class
- Low
- Owner
- Valentine, Linda
Source: USACE National Inventory of Dams, NID ID WI00268 · Operator website
County Ranking
Ranked #4 of 8 lakes in Kenosha County
Nearby Lakes in Kenosha County
Frequently asked questions about Rock Lake
What is the water quality grade for Rock Lake?
- Rock Lake in Kenosha County, Wisconsin has a water quality grade of B (Good). Water clarity: 10 ft visibility. Phosphorus: 15.9 µg/L. Maximum depth: 33 ft. Surface area: 44 acres.
Is Rock Lake safe to swim in?
- Good for swimming, clear water with low algae levels. Rock Lake has a water quality grade of B (Good). Always check local health department advisories before swimming.
What is the water temperature of Rock Lake?
- Rock Lake typically sits around 81°F at the surface in August, from 12 EPA Water Quality Portal field readings (2024–2025). That is a typical value for the month, not a live reading.
How deep is Rock Lake?
- Rock Lake has a maximum depth of 33 feet. The lake covers 44 acres.
What fish are in Rock Lake?
- Fish species found in Rock Lake include Panfish, Largemouth Bass, Trout. Rock Lake is located in Kenosha County, Wisconsin.
Are there boat ramps on Rock Lake?
- Rock Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include 113th Street. Public access is listed as yes.
Explore Rock Lake across LakeGrade
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Moderate nutrients, good water quality
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Where this data comes from
66 measurements from 1 monitoring station, 2020–2026. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX66 samples · 2020–2026
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
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