Rockstad Lake
Rockstad Lake in Clearwater County, Minnesota has a water quality grade of D (Nutrient-rich). Water clarity: 4.3 ft visibility. Phosphorus: 47.5 µg/L. Chlorophyll-a (algae): 28.9 µg/L. Maximum depth: 18 ft. Surface area: 141.52 acres.
- Clarity
- 4.3 ft
- Typical in August
- 71°F
- Max depth
- 18 ft
- Area
- 142 acres
- Type
- Eutrophic
- Trend
- ↓ Declining
- Public access
- Yes
Grade D measures nutrients and algae, not whether this is a good place for a cabin trip. Cabins and rentals near Rockstad Lake →
Next lake in Clearwater County
Rockstad Lake is a 142-acre productive, nutrient-rich eutrophic lake in Clearwater County, Minnesota with a maximum depth of 18 feet. Water quality is graded D based on 2 sampling years through 2025. Overall water quality is declining over recent sampling years. The lake supports 4 documented fish species including black crappie, northern pike, and white sucker. Public access is available with 1 public boat landing. Compared to the 36 other monitored lakes in Clearwater County, Rockstad Lake ranks #36 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-09. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyAlgae risk
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.
Nutrients and algae run higher than average — check local advisories before swimming, and skip the water if you see scum
Water Quality Grade: D (Nutrient-rich)
Murky, only visible to about 4.3 ft. Phosphorus level: 47.5 µg/L. Chlorophyll-a: 28.9 µg/L. Trophic State Index: 60.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 4.3 ft | Not graded |
| Phosphorus | 47.5 µg/L | Poor |
| Chlorophyll-a (Algae) | 28.9 µg/L | Poor |
| Trophic State Index (TSI) | 60 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Rockstad Lake
Compare lakeside cabins, hotels, and vacation rentals near Rockstad Lake in Clearwater 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 Rockstad Lake are listed below.
Top-rated places to stay near Rockstad Lake
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Planning a whole trip? See where to stay at Minnesota’s top lakes →
Water Temperature
Rockstad Lake typically sits around 71°F at the surface in August. Summer average is about 70°F. Usually warmest in Jul (about 73°F) and coldest in Sep (about 62°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 49 field readings (2010–2021) via the EPA Water Quality Portal. See the full Rockstad Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 18 ft |
| Surface Area | 142 acres |
| Shoreline Length | 2 mi |
| Littoral Zone | 86% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Rockstad LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Rockstad Lake
DNR Fisheries Survey Summary
5 surveys on file from MN DNR Fisheries. Most recent: 2014-08-11 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Black Bullhead | 148.28 | 0.2 lb |
| Yellow Perch | 144.66 | 0.16 lb |
| White Sucker | 11.79 | 0.87 lb |
| Brown Bullhead | 5.88 | 0.42 lb |
| Walleye | 5.77 | 0.43 lb |
| Northern Pike | 5.03 | 3.02 lb |
CPUE = catch per unit effort, averaged across surveys (excludes juvenile shoreline seining). Higher CPUE = more abundant in standardized sampling.
Length Distributions
Number of fish caught at each inch class in the most recent survey that recorded lengths. Red dashed line marks an approximate trophy threshold for that species.
Black Bullhead
Yellow Perch
White Sucker
Brown Bullhead
From the 2014-08-11 survey
Rockstad Lake is a 128-acre lake with a maximum depth of 18 feet located near the town of Zerkel in southern Clearwater County. The Minnesota Department of Natural Resources has classified Minnesota's lakes into 43 different lake classes based on physical characteristics, water chemistry and fish community. Rockstad…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Rockstad Lake. 3 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — RockstadFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Rockstad (1693)Aquatic Plant Report · MN DNR LakeFinder
- —Public Water Access Sites — RockstadPublic Water Access Sites · MN DNR LakeFinder
Water Quality Trend: ↓ Declining
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.046 m/yr | 5 |
| Phosphorus | ↓ Declining | +1.31 µg/L/yr | 6 |
| Chlorophyll-a | ↓ Declining | +1.36 µg/L/yr | 6 |
EPA Impairment Status
Rockstad Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN15-0075-00 · Official waterbody report
County Ranking
Ranked #36 of 37 lakes in Clearwater County
Nearby Lakes With Higher Grades
Rockstad Lake holds Grade D. 2 nearby lakes hold higher nutrient-and-algae grades — useful for a swim day, not a reason to skip lodging here.
See full comparison →Nearby Lakes in Clearwater County
Frequently asked questions about Rockstad Lake
What is the water quality grade for Rockstad Lake?
- Rockstad Lake in Clearwater County, Minnesota has a water quality grade of D (Nutrient-rich). Water clarity: 4.3 ft visibility. Phosphorus: 47.5 µg/L. Chlorophyll-a (algae): 28.9 µg/L. Maximum depth: 18 ft. Surface area: 141.52 acres.
Is Rockstad Lake safe to swim in?
- Nutrients and algae run higher than average — check local advisories before swimming, and skip the water if you see scum. Rockstad Lake has a water quality grade of D (Nutrient-rich). Algae concentration (chlorophyll-a) is 28.9 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Rockstad Lake?
- Rockstad Lake typically sits around 71°F at the surface in August, from 49 EPA Water Quality Portal field readings (2010–2021). That is a typical value for the month, not a live reading.
How deep is Rockstad Lake?
- Rockstad Lake has a maximum depth of 18 feet. The lake covers 141.52 acres.
What fish are in Rockstad Lake?
- Fish species found in Rockstad Lake include black crappie, northern pike, white sucker, yellow perch. Rockstad Lake is located in Clearwater County, Minnesota.
Are there boat ramps on Rockstad Lake?
- Rockstad Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Rockstad Lake. Public access is listed as yes.
Explore Rockstad Lake across LakeGrade
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Where this data comes from
76 measurements from 1 monitoring station, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA76 samples · 2020–2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Two Reagent Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
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
Named boat-access points from the USGS National Boat Ramps inventory