Altoona Lake
Altoona Lake in Eau Claire County, Wisconsin has a water quality grade of D (Nutrient-rich). Water clarity: 3 ft visibility. Phosphorus: 99.6 µg/L. Maximum depth: 25 ft. Surface area: 720 acres.
- Clarity
- 3 ft
- Typical in August
- 73°F
- Max depth
- 25 ft
- Area
- 720 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 Altoona Lake →
Next lake in Eau Claire County
Altoona Lake is a 720-acre productive, nutrient-rich eutrophic lake in Eau Claire County, Wisconsin with a maximum depth of 25 feet. Water quality is graded D based on 1 sampling years through 2026. Overall water quality is declining over recent sampling years. The lake supports 4 documented fish species including Musky, Panfish, and Smallmouth Bass. Public access is available with 2 public boat landings. Compared to the 1 other monitored lakes in Eau Claire County, Altoona Lake ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-05-21. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyElevated nutrients
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)
Very murky, less than 3 ft of visibility. Phosphorus level: 99.6 µg/L. Trophic State Index: 66.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 3 ft | Not graded |
| Phosphorus | 99.6 µg/L | Poor |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 66 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Altoona Lake
Compare lakeside cabins, hotels, and vacation rentals near Altoona Lake in Eau Claire County, Wisconsin — 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 Altoona Lake are listed below.
Top-rated places to stay near Altoona Lake
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
Planning a whole trip? See where to stay at Wisconsin’s top lakes →
Water Temperature
Altoona Lake typically sits around 73°F at the surface in August. Summer average is about 74°F. Usually warmest in Jul (about 77°F) and coldest in Mar (about 42°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 64 field readings (2024–2025) via the EPA Water Quality Portal. See the full Altoona Lake water temperature breakdown →
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Altoona Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was high (496,592 cells/mL) on July 18, 2026.
Blue-green algae can appear and clear within days, so check your state’s current advisory before swimming. EPA CyAN ↗
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 25 ft |
| Surface Area | 720 acres |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Lake Altoona County ParkPublic
- Indian Hills DrivePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Altoona 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.
WI DNR Lake Profile
Authoritative data from the Wisconsin DNR LakePages. Monitored by volunteers since 2011. 4 stations on file (most recent sample 2025).
Fish Species (DNR-rated)
DNR Reports & Resources
Wisconsin DNR Fisheries scientists publish multi-year survey reports for Altoona Lake covering fish populations, stocking, water quality, and management. 1 report on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- 2025Lake Altoona spring netting/shocking survey, 2025Netting Survey · WI DNR · 2025 (PDF)
Water Quality Trend: ↓ Declining
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.104 m/yr | 6 |
| Phosphorus | ↓ Declining | +5.1 µg/L/yr | 5 |
Reservoir Info (USACE NID)
Altoona Lake is a man-made reservoir impounded by the Altoona (completed 1938), built primarily for recreation on the Eau Claire River; buttress-type dam, 44 ft tall and 240 ft long.
- Surface area
- 720 ac
- Normal storage
- 8,200 ac-ft
- Max storage
- 14,000 ac-ft
- Drainage area
- 883 sq mi
- Hazard class
- High
- Owner
- Eau Claire County
Source: USACE National Inventory of Dams, NID ID WI00011 · Operator website
EPA Impairment Status
Altoona Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5R).
Causes of impairment
Source: EPA ATTAINS assessment unit WI10004661 · Official waterbody report
Regulated Pollution Sources Nearby
4 EPA-permitted facilities operate within about 5 miles of Altoona Lake under Clean Water Act (NPDES) discharge permits, including 1 classified by the EPA as major discharger. 1 facility has a reported Clean Water Act violation in the past three years.
- Cascades Tissue Group Wisc IncEau Claire · 4.3 mi away · NPDES WI0003077MajorRecent violation
- Lake Altoona Protection & Rehab DistrictAltoona · 0.7 mi away · NPDES WI0049352
- Fairfax Park Municipal SwimminEau Claire · 3.7 mi away · NPDES WI0048721
- Wrr Environmental Services Co IncBrunswick · 4.3 mi away · NPDES WI0058718
Facilities permitted to discharge under the Clean Water Act within ~5 miles; proximity does not by itself mean a facility affects this lake. Source: EPA ECHO (ICIS-NPDES), as of 2026-07.
County Ranking
Ranked #1 of 2 lakes in Eau Claire County
Nearby Lakes in Eau Claire County
Frequently asked questions about Altoona Lake
What is the water quality grade for Altoona Lake?
- Altoona Lake in Eau Claire County, Wisconsin has a water quality grade of D (Nutrient-rich). Water clarity: 3 ft visibility. Phosphorus: 99.6 µg/L. Maximum depth: 25 ft. Surface area: 720 acres.
Is Altoona 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. Altoona Lake has a water quality grade of D (Nutrient-rich). Always check local health department advisories before swimming.
What is the water temperature of Altoona Lake?
- Altoona Lake typically sits around 73°F at the surface in August, from 64 EPA Water Quality Portal field readings (2024–2025). That is a typical value for the month, not a live reading.
How deep is Altoona Lake?
- Altoona Lake has a maximum depth of 25 feet. The lake covers 720 acres.
What fish are in Altoona Lake?
- Fish species found in Altoona Lake include Musky, Panfish, Smallmouth Bass, Walleye. Altoona Lake is located in Eau Claire County, Wisconsin.
Does Altoona Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Altoona Lake (clouds, ice, or an off-season gap). The most recent reading was high (496,592 cells/mL). Blue-green algae can appear and clear within days, so check Wisconsin's current advisory before swimming.
Are there boat ramps on Altoona Lake?
- Altoona Lake has 2 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Lake Altoona County Park, Indian Hills Drive. Public access is listed as yes.
Explore Altoona Lake across LakeGrade
Depth, room, public access, and the state wake-sport rules
Fish species and top-graded lakes across Wisconsin
Fish species and best lakes in Eau Claire County
Species activity outlook by water temperature and season
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Lakes in the Chippewa River Watershed, ranked by water quality
High nutrients, frequent algae, reduced clarity
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Where this data comes from
214 measurements from 2 monitoring stations, 2020–2026. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX214 samples · 2020–2026
Analytical methods
- Phosphorus by Colorimetry
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
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Lake size & watershed from HydroLAKES (HydroSHEDS)
Fish and recreation data from Wisconsin DNR Lakes
Named boat-access points from the USGS National Boat Ramps inventory