Hidden Valley Lake
Hidden Valley Lake in Lafayette County, Wisconsin has a water quality grade of D (Nutrient-rich). Water clarity: 5.2 ft visibility. Phosphorus: 44.7 µg/L. Maximum depth: 18 ft. Surface area: 26 acres.
- Clarity
- 5.2 ft
- Typical in August
- 78°F
- Max depth
- 18 ft
- Area
- 26 acres
- Type
- Eutrophic
- Trend
- ↓ Declining
Grade D measures nutrients and algae, not whether this is a good place for a cabin trip. Cabins and rentals near Hidden Valley Lake →
Next lake in Lafayette County
Hidden Valley Lake is a 26-acre productive, nutrient-rich eutrophic lake in Lafayette County, Wisconsin with a maximum depth of 18 feet. Water quality is graded D based on 1 sampling years through 2026. 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. Grade methodology: LakeGrade methodology.
Watch Hidden Valley Lake water quality
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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)
Murky, only visible to about 5.2 ft. Phosphorus level: 44.7 µg/L. Trophic State Index: 56.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 5.2 ft | Not graded |
| Phosphorus | 44.7 µg/L | Poor |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 56 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay 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 grade measures nutrients and algae, not lodging — cabins and rentals around Hidden Valley Lake are listed below.
Top-rated places to stay near Hidden Valley Lake
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Planning a whole trip? See where to stay at Wisconsin’s top lakes →
Water Temperature
Hidden Valley Lake typically sits around 78°F at the surface in August. 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.
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 →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 18 ft |
| Surface Area | 26 acres |
Fishing Hidden Valley Lake
WI DNR Lake Profile
Authoritative data from the Wisconsin DNR LakePages. Monitored by volunteers since 1993. 1 station on file (most recent sample 2026).
Water Quality Trend: ↓ Declining
Based on 7 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.429 m/yr | 7 |
| Phosphorus | ↓ Declining | +2.29 µg/L/yr | 7 |
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
Source: EPA ATTAINS assessment unit WI10040240 · Official waterbody report · Matched by proximity (0.04 km)
County Ranking
Ranked #1 of 2 lakes in Lafayette County
Nearby Lakes With Higher Grades
Hidden Valley Lake holds Grade D. One nearby lake has a higher nutrient-and-algae grade — useful for a swim day, not a reason to skip lodging here.
See full comparison →Nearby Lakes in Lafayette County
Frequently asked questions about Hidden Valley Lake
What is the water quality grade for Hidden Valley Lake?
- Hidden Valley Lake in Lafayette County, Wisconsin has a water quality grade of D (Nutrient-rich). 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?
- Nutrients and algae run higher than average — check local advisories before swimming, and skip the water if you see scum. Hidden Valley Lake has a water quality grade of D (Nutrient-rich). Always check local health department advisories before swimming.
What is the water temperature of Hidden Valley Lake?
- Hidden Valley Lake typically sits around 78°F at the surface in August, 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)
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
Fish and recreation data from Wisconsin DNR Lakes