North Silver Lake
North Silver Lake in Martin County, Minnesota has a water quality grade of F (Algae-prone). Water clarity: 4.9 ft visibility. Phosphorus: 68 µg/L. Chlorophyll-a (algae): 51.2 µg/L. Surface area: 200 acres.
- Clarity
- 4.9 ft
- Typical in August
- 72°F
- Max depth
- ~30 ft est.
- Area
- 200 acres
- Type
- Eutrophic
- Trend
- ↑ Improving
- Public access
- No
- Ice-out
- Mar 23
- Open water
- 251 days
Grade F measures nutrients and algae, not whether this is a good place for a cabin trip. Cabins and rentals near North Silver Lake →
Next lake in Martin County
North Silver Lake is a 200-acre productive, nutrient-rich eutrophic lake in Martin County, Minnesota with an estimated average depth of about 30 feet. Water quality is graded F based on 2 sampling years through 2025. Overall water quality is improving over recent sampling years. Limited fish-species data available. No public access — the lake is private or restricted. Compared to the 11 other monitored lakes in Martin County, North Silver Lake ranks #9 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-10-30. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyLimited data
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Algae and nutrients are often high — check current advisories before swimming. Skip the water if you see scum or a paint-like bloom
Water Quality Grade: F (Algae-prone)
Murky, only visible to about 4.9 ft. Phosphorus level: 68 µg/L. Chlorophyll-a: 51.2 µg/L. Trophic State Index: 63.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 4.9 ft | Not graded |
| Phosphorus | 68 µg/L | Poor |
| Chlorophyll-a (Algae) | 51.2 µg/L | Poor |
| Trophic State Index (TSI) | 63 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near North Silver Lake
Compare lakeside cabins, hotels, and vacation rentals near North Silver Lake in Martin 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. The water-quality grade measures nutrients and algae, not lodging — cabins and rentals around North Silver Lake are listed below.
Top-rated places to stay near North Silver Lake
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Planning a whole trip? See where to stay at Minnesota’s top lakes →
Water Temperature
North Silver Lake typically sits around 72°F at the surface in August. Summer average is about 77°F. Usually warmest in Jul (about 80°F) and coldest in Oct (about 49°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 20 field readings (2025–2025) via the EPA Water Quality Portal. See the full North Silver Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | ~30 ft est. |
| Average Depth | ~12 ft est. |
| Surface Area | 200 acres |
| Public Access | No |
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Minnesota has not published bathymetry for North Silver Lake.
Lake Size & Watershed
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.
Fishing North Silver Lake
Water Quality Trend: ↑ Improving
Based on 4 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.145 m/yr | 4 |
Ice Season
Historical ice data from Minnesota DNR (30 observations).
Estimated open water season: 251 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2026-03-10 (2026) | 2018-04-29 (2018) |
| Ice-In | 2018-11-10 (2018) | 2015-12-19 (2015) |
Most recent ice-out: 2026-03-10
Reservoir Info (USACE NID)
North Silver Lake is a man-made reservoir impounded by the North Silver Lake (completed 1972), built primarily for recreation on the Blue Earth River-TR; earth-type dam, 8 ft tall.
- Surface area
- 200 ac
- Max storage
- 350 ac-ft
- Drainage area
- 1.1 sq mi
- Hazard class
- Low
- Owner
- Martin County Conservatory Club
Source: USACE National Inventory of Dams, NID ID MN00374 · Operator website
EPA Impairment Status
North Silver Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit MN46-0020-00 · Official waterbody report · Matched by proximity (1.66 km)
County Ranking
Ranked #9 of 12 lakes in Martin County
Nearby Lakes in Martin County
Frequently asked questions about North Silver Lake
What is the water quality grade for North Silver Lake?
- North Silver Lake in Martin County, Minnesota has a water quality grade of F (Algae-prone). Water clarity: 4.9 ft visibility. Phosphorus: 68 µg/L. Chlorophyll-a (algae): 51.2 µg/L. Surface area: 200 acres.
Is North Silver Lake safe to swim in?
- Algae and nutrients are often high — check current advisories before swimming. Skip the water if you see scum or a paint-like bloom. North Silver Lake has a water quality grade of F (Algae-prone). Algae concentration (chlorophyll-a) is 51.2 µg/L. Always check local health department advisories before swimming.
What is the water temperature of North Silver Lake?
- North Silver Lake typically sits around 72°F at the surface in August, from 20 EPA Water Quality Portal field readings (2025–2025). That is a typical value for the month, not a live reading.
How deep is North Silver Lake?
- No published bathymetric survey covers North Silver Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 30 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate. The lake covers 200 acres.
When does North Silver Lake thaw?
- North Silver Lake typically has ice-out around Mar 23. Ice typically forms around Nov 29. The open water season is approximately 251 days.
Explore North Silver Lake across LakeGrade
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Where this data comes from
18 measurements from 1 monitoring station, 2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA18 samples · 2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Colorimetry
- 10200 H 3 ~ Chlorophyll a-b-c Determination by fluorometer
Monitoring station identifiers (1)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database
Lake size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder
Ice data from Minnesota DNR Climate