Webb Lake
Webb Lake in Cass County, Minnesota has a water quality grade of A (Excellent). Water clarity: 18 ft visibility. Phosphorus: 9.5 µg/L. Chlorophyll-a (algae): 2.9 µg/L. Maximum depth: 84 ft. Surface area: 720.03 acres.
- Clarity
- 18 ft
- Typical in August
- 73°F
- Max depth
- 84 ft
- Area
- 720 acres
- Type
- Oligotrophic
- Trend
- ↓ Declining
- Public access
- Yes
- Ice-out
- Apr 22
- Open water
- 217 days
Next lake in Cass County
Webb Lake is a 720-acre cold, clear oligotrophic lake in Cass County, Minnesota with a maximum depth of 84 feet (21-foot average). Water quality is graded A based on 2 sampling years through 2025. Overall water quality is declining over recent sampling years. The lake supports 12 documented fish species including black crappie, bluegill, and hybrid sunfish. Public access is available with 1 public boat landing. Compared to the 103 other monitored lakes in Cass County, Webb Lake ranks #31 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-29. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyLow algae
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.
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A (Excellent)
Crystal clear, you can see 18 ft down. Phosphorus level: 9.5 µg/L. Chlorophyll-a: 2.9 µg/L. Trophic State Index: 38.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 18 ft | Not graded |
| Phosphorus | 9.5 µg/L | Good |
| Chlorophyll-a (Algae) | 2.9 µg/L | Good |
| Trophic State Index (TSI) | 38 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near Webb Lake
Compare lakeside cabins, hotels, and vacation rentals near Webb Lake in Cass 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.
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Water Temperature
Webb Lake typically sits around 73°F at the surface in August. Summer average is about 73°F. Usually warmest in Jul (about 75°F) and coldest in May (about 58°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 62 field readings (2011–2025) via the EPA Water Quality Portal. See the full Webb Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 84 ft |
| Average Depth | 20.9 ft |
| Surface Area | 720 acres |
| Shoreline Length | 7.1 mi |
| Littoral Zone | 39% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Webb LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Webb Lake
DNR Fisheries Survey Summary
12 surveys on file from MN DNR Fisheries. Most recent: 2025-07-14 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| MMS | 273.69 | — |
| Bluntnose Minnow | 58.39 | — |
| Bluegill | 28.65 | 0.13 lb |
| BKF | 21.70 | — |
| BCS | 13.91 | — |
| LGP | 12.79 | — |
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.
Bluegill
From the 2025-07-14 survey
Webb Lake (DOW# 11-0311; Lake Class 27) is a 720-acre lake with 278 littoral acres, 7.1 miles of shoreline and a maximum depth of 84 feet located northeast of Hackensack, MN. There is a Minnesota Department of Natural Resources (MNDNR) owned public access on the south shore. The lake is primarily managed for…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Webb Lake. 4 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — WebbFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Webb (1545)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — WebbFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — WebbPublic 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 | +0.165 m/yr | 6 |
| Phosphorus | ↓ Declining | +0.39 µg/L/yr | 6 |
| Chlorophyll-a | ↓ Declining | +0.15 µg/L/yr | 6 |
Ice Season
Historical ice data from Minnesota DNR (91 observations).
Estimated open water season: 217 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2010-04-02 (2010) | 2013-05-13 (2013) |
| Ice-In | 1977-10-22 (1977) | 1998-12-21 (1998) |
Most recent ice-out: 2022-05-07
EPA Impairment Status
Webb 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 MN11-0311-00 · Official waterbody report
County Ranking
Ranked #31 of 104 lakes in Cass County
Nearby Lakes in Cass County
Frequently asked questions about Webb Lake
What is the water quality grade for Webb Lake?
- Webb Lake in Cass County, Minnesota has a water quality grade of A (Excellent). Water clarity: 18 ft visibility. Phosphorus: 9.5 µg/L. Chlorophyll-a (algae): 2.9 µg/L. Maximum depth: 84 ft. Surface area: 720.03 acres.
Is Webb Lake safe to swim in?
- Excellent for swimming, crystal clear water with minimal algae. Webb Lake has a water quality grade of A (Excellent). Algae concentration (chlorophyll-a) is 2.9 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Webb Lake?
- Webb Lake typically sits around 73°F at the surface in August, from 62 EPA Water Quality Portal field readings (2011–2025). That is a typical value for the month, not a live reading.
How deep is Webb Lake?
- Webb Lake has a maximum depth of 84 feet and an average depth of 20.9 feet. The lake covers 720.03 acres.
What fish are in Webb Lake?
- Fish species found in Webb Lake include black crappie, bluegill, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, rock bass, smallmouth bass, walleye, white sucker, yellow bullhead, yellow perch. Webb Lake is located in Cass County, Minnesota.
When does Webb Lake thaw?
- Webb Lake typically has ice-out around Apr 22. Ice typically forms around Nov 25. The open water season is approximately 217 days.
Are there boat ramps on Webb Lake?
- Webb Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Webb Lake. Public access is listed as yes.
Explore Webb Lake across LakeGrade
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Species activity outlook by water temperature and season
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Where this data comes from
130 measurements from 2 monitoring stations, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA130 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 (2)
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
Ice data from Minnesota DNR Climate