Hartlaub Lake
Hartlaub Lake in Manitowoc County, Wisconsin has a water quality grade of B (Good). Water clarity: 5 ft visibility. Phosphorus: 35.8 µg/L. Maximum depth: 60 ft. Surface area: 37 acres.
- Clarity
- 5 ft
- Max depth
- 60 ft
- Area
- 37 acres
- Type
- Eutrophic
- Trend
- ↑ Improving
- Public access
- Yes
Next lake in Manitowoc County
Hartlaub Lake is a 37-acre productive, nutrient-rich eutrophic lake in Manitowoc County, Wisconsin with a maximum depth of 60 feet. Water quality is graded B based on 1 sampling years through 2026. Overall water quality is improving 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 15 other monitored lakes in Manitowoc County, Hartlaub Lake ranks #3 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-04-12. 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)
Murky, only visible to about 5 ft. Phosphorus level: 35.8 µg/L. Trophic State Index: 55.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 5 ft | Not graded |
| Phosphorus | 35.8 µg/L | Good |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 55 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Hartlaub Lake
Compare lakeside cabins, hotels, and vacation rentals near Hartlaub Lake in Manitowoc 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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Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 60 ft |
| Surface Area | 37 acres |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Hartlaub LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Hartlaub 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 1996. 5 stations on file (most recent sample 2025).
Fish Species (DNR-rated)
Water Quality Trend: ↑ Improving
Based on 7 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | -0.036 m/yr | 6 |
| Phosphorus | ↑ Improving | -6.71 µg/L/yr | 7 |
EPA Impairment Status
Hartlaub Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit WI10000134 · Official waterbody report
County Ranking
Ranked #3 of 16 lakes in Manitowoc County
Nearby Lakes in Manitowoc County
Frequently asked questions about Hartlaub Lake
What is the water quality grade for Hartlaub Lake?
- Hartlaub Lake in Manitowoc County, Wisconsin has a water quality grade of B (Good). Water clarity: 5 ft visibility. Phosphorus: 35.8 µg/L. Maximum depth: 60 ft. Surface area: 37 acres.
Is Hartlaub Lake safe to swim in?
- Good for swimming, clear water with low algae levels. Hartlaub Lake has a water quality grade of B (Good). Always check local health department advisories before swimming.
How deep is Hartlaub Lake?
- Hartlaub Lake has a maximum depth of 60 feet. The lake covers 37 acres.
What fish are in Hartlaub Lake?
- Fish species found in Hartlaub Lake include Panfish, Largemouth Bass, Northern Pike. Hartlaub Lake is located in Manitowoc County, Wisconsin.
Are there boat ramps on Hartlaub Lake?
- Hartlaub Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Hartlaub Lake. Public access is listed as yes.
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Where this data comes from
69 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_WQX69 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
Impairment status from EPA ATTAINS 303(d) database
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