Grass Island Lake
Beltrami County, MinnesotaView mapDirections
No nutrient or algae sampling on record from Minnesota PCA for this lake.
- Limited data
Grass Island Lake in Beltrami County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported.
Grass Island Lake is a lake in Beltrami County, Minnesota. Overall water quality is improving over recent sampling years.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2020-03-03. Methodology: how these readings are compared.
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Grass Island 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 Grass Island Lake
These are the measurements Minnesota PCA publishes for Grass Island 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.
Ask about Grass Island Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Grass Island Lake typically sits around 62°F at the surface in September. Summer average is about 73°F. Usually warmest in Jul (about 79°F) and coldest in Sep (about 62°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (62°F) to its warmest (79°F).
Typical surface water temperature by month, from 13 field readings (2016–2019) via the EPA Water Quality Portal. See the full Grass Island Lake water temperature breakdown →
Stays via Stay22
Stays near Grass Island Lake
Compare lakeside cabins, hotels, and vacation rentals near Grass Island Lake in Beltrami County, Minnesota — 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.
Top-rated places to stay near Grass Island Lake
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Fishing Grass Island Lake
Water Quality Trend: Improving
Based on 6 years of monitoring (2020–2025).
Water clarity
Stable6 years
Phosphorus
Improving-0.57 µg/L/yr6 years
Chlorophyll-a
Stable+0.01 µg/L/yr6 years
Nearby Lakes in Beltrami County
Frequently asked questions about Grass Island Lake
Where is Grass Island Lake?
- Grass Island Lake is a lake in Beltrami County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of Grass Island Lake?
- Grass Island Lake in Beltrami County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported.
Is Grass Island Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
What is the water temperature of Grass Island Lake?
- Grass Island Lake typically sits around 62°F at the surface in September, from 13 EPA Water Quality Portal field readings (2016–2019). That is a typical value for the month, not a live reading.
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Where this data comes from
2 measurements from 1 monitoring station, 2020. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Red Lake DNR
REDLAKE_WQX2 samples · 2020
Analytical methods
- Phosphorus by Two Reagent Colorimetry
- Turbidity by Nephelometry
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.