Lake Five
Washington County, WisconsinMesotrophic
On the LakeGrade rubric, Lake Five pulls an A: clarity at 12.0 ft and 15 µg/L of phosphorus put it in the top bracket for Wisconsin. The three sub-grades — clarity, phosphorus, and chlorophyll-a — track close together, so no single parameter is dragging the average.
The lake sits in the mesotrophic zone — the band where most well-managed Wisconsin lakes fall. Lake Five reaches 23 ft at its deepest point — typical for Wisconsin mid-sized lakes, with seasonal stratification but limited cold-water refuge. Lake Five covers 104 acres alongside partial shoreline records — a mid-sized water that supports a working fishery without being so large that conditions diverge between basins. Among the 15 graded lakes in Washington County, Lake Five sits at rank 5, above the county median.
Eurasian watermilfoil has been documented at Lake Five, requiring shoreline management to keep dense mats from crowding native vegetation. Bass fishing is part of the appeal: the species list runs to 3, anchored by largemouth and/or smallmouth bass. Monitoring depth is thin here: the LakeGrade rubric is applied to a small number of sample years, and the grade will be revised as more data accumulates.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-06-21. Grade methodology: LakeGrade methodology.
Watch Lake Five water quality
Subscribe for LakeQuality updates by email. No spam, unsubscribe anytime.
Swimming Safety
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A, Excellent
Good clarity, visible to about 12 ft. Phosphorus level: 14.7 µg/L. Trophic State Index: 42.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 12 ft | B |
| Phosphorus | 14.7 µg/L | A |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 42 | Mesotrophic |
Moderate nutrients, good water quality
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 23 ft |
| Surface Area | 104 acres |
Fish Species
Click a species to see every graded lake where it is documented.
→ Best fishing times for Lake Five (14-day solunar calendar)
→ Is it safe to eat fish from Lake Five? (mercury & PFAS guide)
→ Lake Five fishing regulations (limits, seasons, special rules)
Invasive & Introduced Species
Red chips are ecologically harmful invasive species. Gray chips are stocked or introduced fish that aren't a current ecological concern.
Water Quality Trend: ↓ Declining
Based on 7 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.527 m/yr | 7 |
| Phosphorus | → Stable | -0.21 µg/L/yr | 6 |
Location
County Ranking
Ranked #5 of 15 lakes in Washington County
Nearby Lakes in Washington County
More Wisconsin Lake Rankings
State Parks Near Lake Five
Other Grade A Lakes in Wisconsin
Mesotrophic Lakes in Wisconsin
WI DNR Lake Profile
Authoritative data from the Wisconsin DNR LakePages. Monitored by volunteers since 1990. 1 station on file (most recent sample 2025).
Fish Species (DNR-rated)
Data Sources
Water quality data from the EPA Water Quality Portal
Grading methodology based on Metropolitan Council standards
Fish and recreation data from Wisconsin DNR Lakes
Most recent sample: 2026-06-21
Monitoring stations: 1
Where to stay near Lake Five
Compare lakeside cabins, hotels, and vacation rentals near Lake Five in Washington County, Wisconsin — live availability and prices for your trip.
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.