Griswold Lake
McHenry County, Illinois153 acresView mapDirections
No nutrient or algae sampling on record from Illinois EPA for this lake.
- Impaired · Mercury
- 13 ft max depth
Griswold Lake in McHenry County, Illinois has water-quality measurements published by Illinois EPA, shown here as reported. Maximum depth: 13 ft. Surface area: 153 acres.
Griswold Lake is a 153-acre lake in McHenry County, Illinois with a maximum depth of 13 feet (5-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. Griswold Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, nutrients (phosphorus, nitrogen). Check local advisories before you swim.
Whether Griswold 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 Griswold Lake
These are the measurements Illinois EPA publishes for Griswold 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 Griswold Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Max depth
13 ft
Average depth
4.5 ft
Surface area
153 acres
Shoreline
3.2 mi
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Stays near Griswold Lake
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Fishing Griswold Lake
EPA Impairment Status
Griswold 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: Fish consumption, Other.
Source: EPA ATTAINS assessment unit IL_RTY · Official waterbody report
Nearby Lakes in McHenry County
Frequently asked questions about Griswold Lake
Where is Griswold Lake?
- Griswold Lake is a lake in McHenry County, Illinois. Its water-quality measurements are published by Illinois EPA and shown on this page as reported.
What is the water quality of Griswold Lake?
- Griswold Lake in McHenry County, Illinois has water-quality measurements published by Illinois EPA, shown here as reported. Maximum depth: 13 ft. Surface area: 153 acres.
Is Griswold Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Griswold Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, nutrients (phosphorus, nitrogen). Check local advisories before you swim.
How deep is Griswold Lake?
- Griswold Lake has a maximum depth of 13 feet and an average depth of 4.5 feet. The lake covers 153 acres.
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Where this data comes from
Measurements for Griswold 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