Where is Middle Lagoon Lake?

Middle Lagoon Lake is a lake in Lake County, Indiana. LakeQuality grades it B for nutrients and algae. The letter is not a swimming clearance.

What is the water temperature of Middle Lagoon Lake?

Middle Lagoon Lake typically sits around 71°F at the surface in September, from 206 EPA Water Quality Portal field readings (2010–2022). That is a typical value for the month, not a live reading.

Middle Lagoon Lake

Lake County, IndianaView map Directions

Good

Clarity, phosphorus, and algae sit in the clean band for this region.

↓ down from A at the last regrade

Water temp

~71°F

Typical for Sep · EPA WQP

Clarity

No sample

Level

No gauge

Trend

Stable

4 years of samples

Oligotrophic
Impaired · PCBs
#2 of 5 in the county
Limited data

See the measurements Directions Where to stay

Middle Lagoon Lake in Lake County, Indiana has a water quality grade of B (Good). Phosphorus: 8.4 µg/L.

Typical in September: 71°F
Type: Oligotrophic
Phosphorus: 8.4 µg/L
Trend: → Stable

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Stays near Middle Lagoon Lake

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Watch Middle Lagoon Lake’s letter

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Middle Lagoon Lake is a cold, clear oligotrophic lake in Lake County, Indiana. Water quality is graded B based on 1 sampling years through 2024. Phosphorus level is declining over recent sampling years. Compared to the 4 other monitored lakes in Lake County, Middle Lagoon Lake ranks #2 for water quality.

Source: EPA Water Quality Portal sampling records, IDEM, last sampled 2024-07-16. Grade methodology: LakeQuality methodology.

Swimming Safety

Grade only

Limited data

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.

The B is nutrients and algae, not a swimming clearance. Middle Lagoon Lake is listed impaired under Clean Water Act §303(d) (IR 5) for pCBs. Check local advisories before you swim.

Compare the safest swimming lakes near Chicago →

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Water Quality Grade: B (Good)

No clarity data. Phosphorus 8.4 µg/L. TSI 35. The letter is not a swimming clearance.

Metric	Value	Grade
Water Clarity (Secchi Depth)	No recent samples
Phosphorus	8.4 µg/L	Good
Chlorophyll-a (Algae)	No recent samples
Trophic State Index (TSI)	35	Oligotrophic

Low nutrients, clear water. The letter is not a swimming clearance.

Water Temperature

Middle Lagoon Lake typically sits around 71°F at the surface in September. Summer average is about 78°F. Usually warmest in Jul (about 79°F) and coldest in May (about 61°F). These are typical values by month — not a live reading.

Jan

—

Feb

—

Mar

—

Apr

—

May

61°

Jun

78°

Jul

79°

Aug

78°

Sep

71°

Oct

—

Nov

—

Dec

—

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 →

Fishing Middle Lagoon Lake

→ Middle Lagoon Lake fishing regulations (limits, seasons, special rules)

Water Quality Trend: → Stable

Based on 4 years of monitoring data (2020-2025).

Metric	Trend	Change/Year	Years
Phosphorus	↓ Declining	+3.05 µg/L/yr	3
Chlorophyll-a	↑ Improving	-1.1 µg/L/yr	2

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

PCBs

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 Dredging
Gary · 3.4 mi away · NPDES IN0061077
MajorRecent violation
United States Steel Corp - Gary Works Facility
Gary · 3.4 mi away · NPDES IN0000281
MajorRecent violation
Illiana Disposal And Recycling Transfer Station # 4 Lake Station
Lake Station · 2 mi away · NPDES INRM01223
Recent violation
Cleveland-Cliffs Plate Llc
Gary · 3.4 mi away · NPDES IN0062197
Recent violation
Lake Street Drainage Improvements & Roadway Reconstruction
Gary · 1.1 mi away · NPDES INRA03777
In Dot Des 1601716 Contract R-39780 Us 12/20 Reconstruction Project - Reconnecti
Gary · 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.

County Ranking

Ranked #2 of 5 lakes in Lake County

Nearby Lakes in Lake County

CGrand Calumet Lagoon LakeMesotrophic0.7 miView →NRGrand Boulevard Lake—View →NRLake George—View →NRLake Holiday—View →NRLake George—View →NRLake George—View →

Frequently asked questions about Middle Lagoon Lake

Where is Middle Lagoon Lake?: Middle Lagoon Lake is a lake in Lake County, Indiana. LakeQuality grades it B for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Middle Lagoon Lake?: Middle Lagoon Lake in Lake County, Indiana has a water quality grade of B (Good). Phosphorus: 8.4 µg/L.
Is Middle Lagoon Lake safe to swim in?: The B is nutrients and algae, not a swimming clearance. Middle Lagoon Lake is listed impaired under Clean Water Act §303(d) (IR 5) for pCBs. Check local advisories before you swim.
What is the water temperature of Middle Lagoon Lake?: Middle Lagoon Lake typically sits around 71°F at the surface in September, from 206 EPA Water Quality Portal field readings (2010–2022). That is a typical value for the month, not a live reading.

Explore Middle Lagoon Lake across LakeQuality

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Planning a trip around Indiana Dunes?

Middle Lagoon Lake is about 9 miles from Indiana Dunes National Park. Crowds there swing hard by season, so the month you pick changes both how busy the park is and what lodging costs.

Best time to visit Indiana Dunes →

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Where this data comes from

5 measurements from 1 monitoring station, 2020–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.

Collected and reported by

National Park Service Water Resources Division11NPSWRD_WQX5 samples · 2020–2024

Analytical methods

Alkaline Persulfate Digestion for Total N and P in Water

Monitoring station identifiers (1)

11NPSWRD_WQX-INDU_05

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)