Milwaukee Harbor Lake
Milwaukee Harbor Lake in Milwaukee County, Wisconsin is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 8.2 ft visibility. Phosphorus: 13 µg/L. Chlorophyll-a (algae): 12 µg/L.
- Clarity
- 8.2 ft
- Typical in August
- 68°F
- Trend
- ↓ Declining
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Why Milwaukee Harbor Lake has no grade
We grade a lake only when its monitoring record clears the evidence bar: at least three phosphorus or chlorophyll-a samples in the last ten years, scored against EPA National Lakes Assessment thresholds for this lake’s ecoregion. For Milwaukee Harbor Lake, no EPA ecoregion for this lake, so the National Lakes Assessment condition thresholds cannot be applied. Sampling here has recorded water clarity, phosphorus and algae (chlorophyll-a).
Not Rated is not an F. It is EPA Integrated Reporting Category 3 — insufficient information. The water here may be excellent or poor; nobody has measured enough of it to say. Everything below that has been measured is still reported on this page.
Sampling is run by WI DNR and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
Milwaukee Harbor Lake is a lake in Milwaukee County, Wisconsin. Overall water quality is declining over recent sampling years.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2025-11-05. Grade methodology: LakeGrade methodology.
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Swimming Safety
Not ratedBacteria C · advisory
Based on E. coli testing, Milwaukee Harbor Lake occasionally exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 5.3% of 208 samples across 8 seasons.
This is a historical summary of past testing, not a current condition — bacteria levels change quickly, especially after rain. Always check Wisconsin’s current beach and health-department advisories before swimming.
Water quality measurements for Milwaukee Harbor Lake
These readings exist but do not meet the evidence bar for an A–F grade — see why.
Moderate clarity, visible to about 8.2 ft. Phosphorus level: 13 µg/L. Chlorophyll-a: 12 µg/L. Trophic State Index: 48.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 8.2 ft | Not graded |
| Phosphorus | 13 µg/L | Not graded |
| Chlorophyll-a (Algae) | 12 µg/L | Not graded |
| Trophic State Index (TSI) | 48 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Milwaukee Harbor Lake
Compare lakeside cabins, hotels, and vacation rentals near Milwaukee Harbor Lake in Milwaukee 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 Milwaukee Harbor Lake
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Water Temperature
Milwaukee Harbor Lake typically sits around 68°F at the surface in August. Summer average is about 63°F. Usually warmest in Sep (about 70°F) and coldest in Mar (about 41°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 244 field readings (2024–2025) via the EPA Water Quality Portal.
Fishing Milwaukee Harbor Lake
Water Quality Trend: ↓ Declining
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.14 m/yr | 6 |
| Phosphorus | ↓ Declining | +2.67 µg/L/yr | 6 |
| Chlorophyll-a | ↓ Declining | +6.82 µg/L/yr | 6 |
EPA Impairment Status
Milwaukee Harbor Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit WI10008753 · Official waterbody report · Matched by proximity (1.34 km)
Graded lakes near Milwaukee Harbor Lake
Milwaukee Harbor Lake has no grade, but these lakes within a short drive do.
Nearby Lakes in Milwaukee County
Frequently asked questions about Milwaukee Harbor Lake
Where is Milwaukee Harbor Lake?
- Milwaukee Harbor Lake is a lake in Milwaukee County, Wisconsin. LakeQuality has not rated this lake (UNRATED) — there is not enough recent sampling to assign a letter.
What is the water quality grade for Milwaukee Harbor Lake?
- Milwaukee Harbor Lake in Milwaukee County, Wisconsin is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 8.2 ft visibility. Phosphorus: 13 µg/L. Chlorophyll-a (algae): 12 µg/L.
Is Milwaukee Harbor Lake safe to swim in?
- Based on E. coli testing, Milwaukee Harbor Lake occasionally exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 5.3% of 208 samples across 8 seasons. That works out to a bacteria swim-safety grade of C — a historical summary of past testing, not a current reading. Milwaukee Harbor Lake is not rated for water quality — its monitoring record does not meet the evidence bar. Bacteria levels can spike quickly after heavy rain, so always check Wisconsin's current beach and health-department advisories before you swim.
What is the water temperature of Milwaukee Harbor Lake?
- Milwaukee Harbor Lake typically sits around 68°F at the surface in August, from 244 EPA Water Quality Portal field readings (2024–2025). That is a typical value for the month, not a live reading.
Explore Milwaukee Harbor Lake across LakeGrade
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Where this data comes from
1,448 measurements from 1 monitoring station, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Milwaukee Metropolitan Sewerage District
WI_MMSD1,448 samples · 2020–2025
Analytical methods
- Phosphorus by Colorimetry
- Total Phosphorus After Block Digestion
- 10200 H ~ Chlorophyll a-b-c Determination
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