Milwaukee Harbor Lake
Milwaukee County, WisconsinView mapDirections
Wisconsin DNR publishes the water-quality measurements for Milwaukee Harbor Lake. Here is what has been measured.
- Limited data
Milwaukee Harbor Lake in Milwaukee County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 8.2 ft visibility. Phosphorus: 13 µg/L. Chlorophyll-a (algae): 12 µg/L.
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. Methodology: how these readings are compared.
Swimming conditions
No readingBacteria tested: exceedances
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.
Whether Milwaukee Harbor Lake is safe to swim in today is a call for the Wisconsin Department of Natural Resources and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Milwaukee Harbor Lake
These are the measurements Wisconsin DNR publishes for Milwaukee Harbor Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Moderate clarity, visible to about 8.2 ft. Phosphorus 13 µg/L. Chlorophyll-a 12 µg/L. TSI 48.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 8.2ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 13µg/L | Measured, not scored The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. |
| Chlorophyll-a (algae) | 12µg/L | Measured, not scored The green pigment in algae — a direct measure of how much algae is in the water. |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 48 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Milwaukee Harbor Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Milwaukee Harbor Lake typically sits around 64°F at the surface in October. 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.
Column height runs from this lake’s coldest month (41°F) to its warmest (70°F).
Typical surface water temperature by month, from 244 field readings (2024–2025) via the EPA Water Quality Portal. See the full Milwaukee Harbor Lake water temperature breakdown →
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Stays near Milwaukee Harbor Lake
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Fishing Milwaukee Harbor Lake
Water Quality Trend: Worsening
Based on 6 years of monitoring (2020–2025).
Water clarity
Worsening6 years
Phosphorus
Worsening+2.67 µg/L/yr6 years
Chlorophyll-a
Worsening+6.82 µg/L/yr6 years
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. Its water-quality measurements are published by Wisconsin DNR and shown on this page as reported.
What is the water quality of Milwaukee Harbor Lake?
- Milwaukee Harbor Lake in Milwaukee County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. 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 is a historical summary of past bacteria testing, not a current reading and not a swimming clearance. Bacteria levels can spike quickly after heavy rain, so whether Milwaukee Harbor Lake is safe to swim in today is a call for Wisconsin's water agency and the county health department; check their current beach advisories before you swim.
What is the water temperature of Milwaukee Harbor Lake?
- Milwaukee Harbor Lake typically sits around 64°F at the surface in October, from 244 EPA Water Quality Portal field readings (2024–2025). That is a typical value for the month, not a live reading.
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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)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.
Other records on this page
Fish and recreation data from Wisconsin DNR Lakes