Wirth Lake
Wirth Lake in Hennepin County, Minnesota has a water quality grade of C (Fair). Water clarity: 10.1 ft visibility. Phosphorus: 34 µg/L. Chlorophyll-a (algae): 5.8 µg/L. Maximum depth: 25 ft. Surface area: 39.97 acres.
- Clarity
- 10.1 ft
- Typical in August
- 66°F
- Max depth
- 25 ft
- Area
- 40 acres
- Type
- Mesotrophic
- Trend
- → Stable
- Public access
- Yes
- Ice-out
- Apr 4
- Open water
- 236 days
Next lake in Hennepin County
Wirth Lake is a 40-acre mesotrophic lake in Hennepin County, Minnesota with a maximum depth of 25 feet. Water quality is graded C based on 2 sampling years through 2025. The lake supports 9 documented fish species including black bullhead, black crappie, and bluegill. Public access is available with 1 public boat landing. Compared to the 80 other monitored lakes in Hennepin County, Wirth Lake ranks #18 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 onlyBacteria A
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.
Based on E. coli testing, Wirth Lake never exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 0% of 6 samples across 6 seasons.
This is a historical summary of past testing, not a current condition — bacteria levels change quickly, especially after rain. Always check Minnesota’s current beach and health-department advisories before swimming.
Water Quality Grade: C (Fair)
Good clarity, visible to about 10.1 ft. Phosphorus level: 34 µg/L. Chlorophyll-a: 5.8 µg/L. Trophic State Index: 49.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 10.1 ft | Not graded |
| Phosphorus | 34 µg/L | Fair |
| Chlorophyll-a (Algae) | 5.8 µg/L | Good |
| Trophic State Index (TSI) | 49 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Wirth Lake
Compare lakeside cabins, hotels, and vacation rentals near Wirth Lake in Hennepin 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 Wirth Lake
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Water Temperature
Wirth Lake typically sits around 66°F at the surface in August. Summer average is about 64°F. Usually warmest in Jul (about 66°F) and coldest in Jan (about 38°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 1,082 field readings (2010–2025) via the EPA Water Quality Portal. See the full Wirth Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 25 ft |
| Surface Area | 40 acres |
| Shoreline Length | 1.2 mi |
| Littoral Zone | 58% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Theo Wirth LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Wirth Lake
Invasive & Introduced Species
Red chips are ecologically harmful invasive species. Gray chips are stocked or introduced fish that aren't a current ecological concern.
DNR Fisheries Survey Summary
9 surveys on file from MN DNR Fisheries. Most recent: 2018-08-07 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Black Crappie | 54.01 | 0.16 lb |
| Black Bullhead | 40.04 | 0.35 lb |
| Bluegill | 22.22 | 0.12 lb |
| Yellow Perch | 4.20 | 0.09 lb |
| Channel Catfish | 4.04 | 0.9 lb |
| Pumpkinseed | 3.31 | 0.11 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 Crappie
Black Bullhead
Bluegill
Yellow Perch
From the 2018-08-07 survey
Wirth Lake is part of Fishing in the Neighborhood (FiN). It is located within the city limits of Golden Valley but is surrounded by Theodore Wirth Park which is administered by the City of Minneapolis. Wirth Lake has a public fishing pier and boat launch that provide access for fishing. Bluegill abundance was…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Wirth Lake. 3 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — WirthFisheries Lake Survey · MN DNR LakeFinder
- —Fish Stocking History — WirthFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — WirthPublic Water Access Sites · MN DNR LakeFinder
Water Quality Trend: → Stable
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | +0.034 m/yr | 6 |
| Phosphorus | → Stable | +0.41 µg/L/yr | 6 |
| Chlorophyll-a | → Stable | +0.05 µg/L/yr | 6 |
Ice Season
Historical ice data from Minnesota DNR (140 observations).
Estimated open water season: 236 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2024-03-04 (2024) | 2013-04-27 (2013) |
| Ice-In | 1991-11-04 (1991) | 2024-01-16 (2024) |
Most recent ice-out: 2024-03-04
EPA Impairment Status
Wirth 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 MN27-0037-00 · Official waterbody report
County Ranking
Ranked #18 of 81 lakes in Hennepin County
Nearby Lakes With Higher Grades
Wirth Lake holds Grade C. 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 Hennepin County
Frequently asked questions about Wirth Lake
What is the water quality grade for Wirth Lake?
- Wirth Lake in Hennepin County, Minnesota has a water quality grade of C (Fair). Water clarity: 10.1 ft visibility. Phosphorus: 34 µg/L. Chlorophyll-a (algae): 5.8 µg/L. Maximum depth: 25 ft. Surface area: 39.97 acres.
Is Wirth Lake safe to swim in?
- Based on E. coli testing, Wirth Lake never exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 0% of 6 samples across 6 seasons. That works out to a bacteria swim-safety grade of A — a historical summary of past testing, not a current reading. Wirth Lake has a water quality grade of C (Fair). Bacteria levels can spike quickly after heavy rain, so always check Minnesota's current beach and health-department advisories before you swim.
What is the water temperature of Wirth Lake?
- Wirth Lake typically sits around 66°F at the surface in August, from 1,082 EPA Water Quality Portal field readings (2010–2025). That is a typical value for the month, not a live reading.
How deep is Wirth Lake?
- Wirth Lake has a maximum depth of 25 feet. The lake covers 39.97 acres.
What fish are in Wirth Lake?
- Fish species found in Wirth Lake include black bullhead, black crappie, bluegill, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, white sucker, yellow bullhead. Wirth Lake is located in Hennepin County, Minnesota.
When does Wirth Lake thaw?
- Wirth Lake typically has ice-out around Apr 4. Ice typically forms around Nov 26. The open water season is approximately 236 days.
Are there boat ramps on Wirth Lake?
- Wirth Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Theo Wirth Lake. Public access is listed as yes.
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Where this data comes from
727 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
MNPCA727 samples · 2020–2025
Analytical methods
- Field measurement/observation, generic method
- 4500 P E ~ Phosphorus in Water by Colorimetry- Ascorbic Acid Method
- 10200 H ~ Chlorophyll a-b-c Determination
- Turbidity, Nephelometric Method
- Turbidity, Probe Method
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
Ice data from Minnesota DNR Climate