Middle Lagoon Lake is a mesotrophic lake in Lake County, Indiana. Water quality is graded A based on 1 sampling years through 2024. Phosphorus level is declining over recent sampling years. Compared to the 6 other monitored lakes in Lake County, Middle Lagoon Lake ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, Indiana DNR, last sampled 2024-09-18. Grade methodology: LakeGrade methodology.
Watch Middle Lagoon Lake water quality
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Swimming Safety
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A, Excellent
No clarity data. Phosphorus level: 14.8 µg/L. Trophic State Index: 43.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No data | |
| Phosphorus | 14.8 µg/L | A |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 43 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Middle Lagoon Lake
Compare lakeside cabins, hotels, and vacation rentals near Middle Lagoon Lake in Lake County, Indiana — 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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Fishing Middle Lagoon Lake
Water Quality Trend: → Stable
Based on 4 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Phosphorus | ↓ Declining | +3.5 µg/L/yr | 3 |
| Chlorophyll-a | ↑ Improving | -1.1 µg/L/yr | 2 |
Water Temperature
Middle Lagoon Lake averages about 78°F at the surface in summer, usually warmest in Jul (about 79°F) and coldest in May (about 61°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 206 field readings (2010–2022) via the EPA Water Quality Portal. See the full Middle Lagoon Lake water temperature breakdown →
Location
County Ranking
Ranked #1 of 7 lakes in Lake County
Nearby Lakes in Lake County
Explore Middle Lagoon Lake across LakeGrade
More Indiana Lake Rankings
Mesotrophic Lakes in Indiana
More records, surveys & data sources
EPA Impairment Status
Middle Lagoon 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 INC01P1083_00 · Official waterbody report · Matched by proximity (0.63 km)
Regulated Pollution Sources Nearby
53 EPA-permitted facilities operate within about 5 miles of Middle Lagoon Lake under Clean Water Act (NPDES) discharge permits, including 2 classified by the EPA as major dischargers. 4 facilities have a reported Clean Water Act violation in the past three years.
- Us Grand Calumet DredgingGary · 3.4 mi away · NPDES IN0061077MajorRecent violation
- United States Steel Corp - Gary Works FacilityGary · 3.4 mi away · NPDES IN0000281MajorRecent violation
- Illiana Disposal And Recycling Transfer Station # 4 Lake StationLake Station · 2 mi away · NPDES INRM01223Recent violation
- Cleveland-Cliffs Plate LlcGary · 3.4 mi away · NPDES IN0062197Recent violation
- Lake Street Drainage Improvements & Roadway ReconstructionGary · 1.1 mi away · NPDES INRA03777
- In Dot Des 1601716 Contract R-39780 Us 12/20 Reconstruction Project - ReconnectiGary · 1.2 mi away · NPDES INRA05988
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.
Data Sources
Water quality data from the EPA Water Quality Portal
Impairment status from EPA ATTAINS 303(d) database
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Grading methodology based on Metropolitan Council standards
Most recent sample: 2024-09-18
Monitoring stations: 1