Norris Lake
Mahnomen County, MinnesotaView mapDirections
Minnesota PCA publishes the water-quality measurements for Norris Lake. Here is what has been measured.
- Mesotrophic
- 22 ft max depth
- Limited data
Norris Lake in Mahnomen County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 11.6 ft visibility. Phosphorus: 15 µg/L. Chlorophyll-a (algae): 3.2 µg/L.
Norris Lake is a mesotrophic lake in Mahnomen County, Minnesota with an estimated average depth of about 22 feet. Compared to the 11 other monitored lakes in Mahnomen County, Norris Lake ranks #6 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-09. Methodology: how these readings are compared.
What Norris Lake is good for
From access and monitoring records, not editorial picks.
- Clear water11.6 ft of visibility
Swimming conditions
Readings onlyLimited data
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Norris 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 Norris Lake
These are the measurements Minnesota PCA publishes for Norris Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Good clarity, visible to about 11.6 ft. Phosphorus 15 µg/L. Chlorophyll-a 3.2 µg/L. TSI 42.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 11.6ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 15µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | 3.2µg/L | Good GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 42 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Norris Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Max depth
~22 ft est.
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Minnesota has not published bathymetry for Norris Lake.
Lake Size & Watershed
Watershed (drainage) area
1 sq mi
HydroLAKES / HydroSHEDS
Surface area
40 acres
HydroLAKES / HydroSHEDS
Shoreline
1.4 mi
HydroLAKES / HydroSHEDS
Elevation
1,647 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth here is modelled, not surveyed — HydroLAKES v1.0 estimates lake depth from surrounding terrain rather than from soundings. Treat it as an approximation, and prefer a state bathymetric survey where one exists.
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Stays near Norris Lake
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Fishing Norris Lake
Nearby Lakes in Mahnomen County
Frequently asked questions about Norris Lake
Where is Norris Lake?
- Norris Lake is a lake in Mahnomen County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of Norris Lake?
- Norris Lake in Mahnomen County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 11.6 ft visibility. Phosphorus: 15 µg/L. Chlorophyll-a (algae): 3.2 µg/L.
Is Norris Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
How deep is Norris Lake?
- No published bathymetric survey covers Norris Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 22 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate.
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Where this data comes from
34 measurements from 2 monitoring stations, 2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Chippewa Tribe, Minnesota (White Earth Band) (Tribal)
WEARTH_WQX34 samples · 2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Two Reagent Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- Turbidity by Nephelometry
Monitoring station identifiers (2)
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
Lake size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder