Saint Marys Lake
Lake County, Illinois106 acresView mapDirections
No nutrient or algae sampling on record from Illinois EPA for this lake.
- Impaired · Nutrients (phosphorus, nitrogen)
- 18 ft max depth
Saint Marys Lake in Lake County, Illinois has water-quality measurements published by Illinois EPA, shown here as reported. Maximum depth: 18 ft. Surface area: 106 acres.
Saint Marys Lake is a 106-acre lake in Lake County, Illinois with a maximum depth of 18 feet (9-foot average).
Source: EPA Water Quality Portal sampling records, Illinois EPA. Methodology: how these readings are compared.
Swimming conditions
No readingNot rated
Nutrient and algae readings are not a swimming clearance. Saint Marys Lake is listed impaired under Clean Water Act §303(d) (IR 5) for nutrients (phosphorus, nitrogen), turbidity. Check local advisories before you swim.
Whether Saint Marys Lake is safe to swim in today is a call for the Illinois Environmental Protection Agency and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Saint Marys Lake
These are the measurements Illinois EPA publishes for Saint Marys Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
No clarity data. TSI undefined.
Ask about Saint Marys Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Max depth
18 ft
Average depth
9 ft
Surface area
106 acres
Shoreline
3.5 mi
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Stays near Saint Marys Lake
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Fishing Saint Marys Lake
EPA Impairment Status
Saint Marys Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Designated uses not supporting: Other.
Source: EPA ATTAINS assessment unit IL_UGF · Official waterbody report
Nearby Lakes in Lake County
Frequently asked questions about Saint Marys Lake
Where is Saint Marys Lake?
- Saint Marys Lake is a lake in Lake County, Illinois. Its water-quality measurements are published by Illinois EPA and shown on this page as reported.
What is the water quality of Saint Marys Lake?
- Saint Marys Lake in Lake County, Illinois has water-quality measurements published by Illinois EPA, shown here as reported. Maximum depth: 18 ft. Surface area: 106 acres.
Is Saint Marys Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Saint Marys Lake is listed impaired under Clean Water Act §303(d) (IR 5) for nutrients (phosphorus, nitrogen), turbidity. Check local advisories before you swim.
How deep is Saint Marys Lake?
- Saint Marys Lake has a maximum depth of 18 feet and an average depth of 9 feet. The lake covers 106 acres.
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Where this data comes from
Measurements for Saint Marys Lake come from the EPA Water Quality Portal. Per-sample source details are not recorded for this lake.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database