South Grave Lake
Itasca County, MinnesotaView mapDirections
Minnesota PCA publishes the water-quality measurements for South Grave Lake. Here is what has been measured.
- Impaired · Mercury
- Public access
- Limited data
South Grave Lake in Itasca County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 9.5 ft visibility.
South Grave Lake is a lake in Itasca County, Minnesota. Overall water quality is declining over recent sampling years. Limited fish-species data available. Public access is available.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2024-10-08. Methodology: how these readings are compared.
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. South Grave Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury. Check local advisories before you swim.
Whether South Grave Lake is safe to swim in today is a call for the Minnesota Pollution Control Agency and the Minnesota DNR and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for South Grave Lake
These are the measurements Minnesota PCA publishes for South Grave 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 9.5 ft. TSI 45.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 9.5ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | No reading The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. | |
| Chlorophyll-a (algae) | No reading 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. | 45 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about South Grave Lake
Answers come straight from the public measurements and survey records on this page.
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for South Grave Lake. 1 report on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Public Water Access Sites — South GravePublic Water Access Sites · MN DNR LakeFinder
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Fishing South Grave Lake
Water Quality Trend: Worsening
Based on 4 years of monitoring (2021–2024).
Water clarity
Worsening4 years
EPA Impairment Status
South Grave Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
Designated uses not supporting: Fish consumption.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN31-0624-02 · Official waterbody report
Nearby Lakes in Itasca County
Frequently asked questions about South Grave Lake
Where is South Grave Lake?
- South Grave Lake is a lake in Itasca County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of South Grave Lake?
- South Grave Lake in Itasca County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 9.5 ft visibility.
Is South Grave Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. South Grave Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury. Check local advisories before you swim.
Can I fish at South Grave Lake?
- Public access to South Grave Lake is listed as yes on the lake record. Seasons, size and bag limits, and whether you need a license are set by Minnesota's fish and wildlife agency, so check its current regulations before you go.
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Where this data comes from
6 measurements from 1 monitoring station, 2023–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA6 samples · 2023–2024
Analytical methods
- Field measurement/observation, generic method
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
Impairment status from EPA ATTAINS 303(d) database