Hidden Valley Lake
Lafayette County, Wisconsin26 acresView mapDirections
Wisconsin DNR publishes the water-quality measurements for Hidden Valley Lake. Here is what has been measured.
- Eutrophic
- Impaired · Nutrients (phosphorus, nitrogen)
- 18 ft max depth
Hidden Valley Lake in Lafayette County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 5.2 ft visibility. Phosphorus: 44.7 µg/L. Maximum depth: 18 ft. Surface area: 26 acres.
Hidden Valley Lake is a 26-acre productive, nutrient-rich eutrophic lake in Lafayette County, Wisconsin with a maximum depth of 18 feet. Overall water quality is declining over recent sampling years. Compared to the 1 other monitored lakes in Lafayette County, Hidden Valley Lake ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-06-27. Methodology: how these readings are compared.
Swimming conditions
Readings onlyRecreation use not supported
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Hidden Valley Lake is listed impaired under Clean Water Act §303(d) (IR 5) for nutrients (phosphorus, nitrogen). Check local advisories before you swim.
Whether Hidden Valley Lake is safe to swim in today is a call for the Wisconsin Department of Natural Resources and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Hidden Valley Lake
These are the measurements Wisconsin DNR publishes for Hidden Valley Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Murky, only visible to about 5.2 ft. Phosphorus 44.7 µg/L. TSI 56.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 5.2ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 44.7µg/L | Poor GoodFairPoor |
| Chlorophyll-a (algae) | No reading The green pigment in algae — a direct measure of how much algae is in the water. | |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 56 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Hidden Valley Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Hidden Valley Lake typically sits around 59°F at the surface in October. Summer average is about 78°F. Usually warmest in Jul (about 80°F) and coldest in Oct (about 59°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (59°F) to its warmest (80°F).
Typical surface water temperature by month, from 26 field readings (2024–2026) via the EPA Water Quality Portal. See the full Hidden Valley Lake water temperature breakdown →
WI DNR Lake Profile
Authoritative data from the Wisconsin DNR LakePages. Monitored by volunteers since 1993. 1 station on file (most recent sample 2026).
Lake Details
Max depth
18 ft
Surface area
26 acres
Stays via Stay22
Stays near Hidden Valley Lake
Compare lakeside cabins, hotels, and vacation rentals near Hidden Valley Lake in Lafayette 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 readings cover nutrients and algae, not lodging. Cabins and rentals around Hidden Valley Lake are listed below.
Top-rated places to stay near Hidden Valley Lake
Prices for Oct 9–11, 4 adults. Change dates on the map below.
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Fishing Hidden Valley Lake
Water Quality Trend: Worsening
Based on 7 years of monitoring (2020–2026).
Water clarity
Worsening7 years
Phosphorus
Worsening+2.29 µg/L/yr7 years
Reservoir Info (USACE NID)
Hidden Valley Lake is a man-made reservoir impounded by the Hidden Valley Lake (completed 1975), built primarily for recreation on the VAN METER CREEK; earth-type dam, 35 ft tall and 720 ft long.
- Surface area
- 22 ac
- Normal storage
- 247 ac-ft
- Max storage
- 500 ac-ft
- Drainage area
- 1 sq mi
- Hazard class
- Low
- Owner
- Hidden Valley Homeowners Association
Source: USACE National Inventory of Dams, NID ID WI00855 · Operator website
EPA Impairment Status
Hidden Valley Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Designated uses not supporting: Aquatic life, Recreation.
Source: EPA ATTAINS assessment unit WI10040240 · Official waterbody report
Nearby Lakes in Lafayette County
Frequently asked questions about Hidden Valley Lake
Where is Hidden Valley Lake?
- Hidden Valley Lake is a lake in Lafayette County, Wisconsin. Its water-quality measurements are published by Wisconsin DNR and shown on this page as reported.
What is the water quality of Hidden Valley Lake?
- Hidden Valley Lake in Lafayette County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 5.2 ft visibility. Phosphorus: 44.7 µg/L. Maximum depth: 18 ft. Surface area: 26 acres.
Is Hidden Valley Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Hidden Valley Lake is listed impaired under Clean Water Act §303(d) (IR 5) for nutrients (phosphorus, nitrogen). Check local advisories before you swim.
What is the water temperature of Hidden Valley Lake?
- Hidden Valley Lake typically sits around 59°F at the surface in October, from 26 EPA Water Quality Portal field readings (2024–2026). That is a typical value for the month, not a live reading.
How deep is Hidden Valley Lake?
- Hidden Valley Lake has a maximum depth of 18 feet. The lake covers 26 acres.
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Where this data comes from
110 measurements from 1 monitoring station, 2020–2026. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX110 samples · 2020–2026
Analytical methods
- Phosphorus by Colorimetry
Monitoring station identifiers (1)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database
Fish and recreation data from Wisconsin DNR Lakes