Crystal Lake
Crystal Lake in Sheboygan County, Wisconsin has a water quality grade of B (Good). Water clarity: 20 ft visibility. Phosphorus: 12.3 µg/L.
- Clarity
- 20 ft
- Typical in August
- 77°F
- Type
- Oligotrophic
- Trend
- → Stable
- Public access
- Yes
Next lake in Sheboygan County
Crystal Lake is a cold, clear oligotrophic lake in Sheboygan County, Wisconsin. Water quality is graded B based on 1 sampling years through 2026. Water clarity is improving over recent sampling years. Limited fish-species data available. Public access is available with 1 public boat landing. Compared to the 5 other monitored lakes in Sheboygan County, Crystal Lake ranks #3 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-07-13. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyLow algae
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)
Crystal clear, you can see 20 ft down. Phosphorus level: 12.3 µg/L. Trophic State Index: 37.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 20 ft | Not graded |
| Phosphorus | 12.3 µg/L | Good |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 37 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near Crystal Lake
Compare lakeside cabins, hotels, and vacation rentals near Crystal Lake in Sheboygan 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.
Top-rated places to stay near Crystal Lake
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Water Temperature
Crystal Lake typically sits around 77°F at the surface in August. Summer average is about 78°F. Usually warmest in Jul (about 83°F) and coldest in May (about 66°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 32 field readings (2024–2026) via the EPA Water Quality Portal. See the full Crystal Lake water temperature breakdown →
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Crystal LakePublic
Fishing Crystal Lake
Water Quality Trend: → Stable
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.802 m/yr | 6 |
| Phosphorus | ↓ Declining | +0.93 µg/L/yr | 5 |
EPA Impairment Status
Crystal 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 WI10001225 · Official waterbody report · Matched by proximity (2.68 km)
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Crystal Lake under Clean Water Act (NPDES) discharge permits. 1 facility has a reported Clean Water Act violation in the past three years.
- Northern Moraine Utility CommissionGlenbeulah · 4.2 mi away · NPDES WI0060879Recent violation
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 #3 of 6 lakes in Sheboygan County
Nearby Lakes in Sheboygan County
Frequently asked questions about Crystal Lake
What is the water quality grade for Crystal Lake?
- Crystal Lake in Sheboygan County, Wisconsin has a water quality grade of B (Good). Water clarity: 20 ft visibility. Phosphorus: 12.3 µg/L.
Is Crystal Lake safe to swim in?
- Good for swimming, clear water with low algae levels. Crystal Lake has a water quality grade of B (Good). Always check local health department advisories before swimming.
What is the water temperature of Crystal Lake?
- Crystal Lake typically sits around 77°F at the surface in August, from 32 EPA Water Quality Portal field readings (2024–2026). That is a typical value for the month, not a live reading.
How deep is Crystal Lake?
- The available depth estimate for Crystal Lake is shallower than its measured water clarity, which cannot be right, so no depth is shown.
Are there boat ramps on Crystal Lake?
- Crystal Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Crystal Lake. Public access is listed as yes.
Explore Crystal Lake across LakeGrade
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Where this data comes from
64 measurements from 2 monitoring stations, 2021–2026. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX64 samples · 2021–2026
Analytical methods
- Phosphorus by Colorimetry
Monitoring station identifiers (2)
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)
Named boat-access points from the USGS National Boat Ramps inventory