Lake Beulah
Walworth County, WisconsinMesotrophic
Lake Beulah sits at the top of the Wisconsin DNR grading rubric with an A, a mark reached by the cleanest lakes in Wisconsin. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.
Mesotrophic conditions dominate at Lake Beulah: enough nutrients for a healthy fishery, not so much that algal blooms become a chronic problem. Lake Beulah is unusually deep for Wisconsin at 58 ft, which buffers the lake against summer warming and helps the deep water stay oxygenated. The lake's 812 acres and partial shoreline records put it in the mid-range bucket — large enough for varied use, small enough that watershed inputs reach the whole basin. Lake Beulah ranks 5 of 35 in Walworth County, putting it in the upper tier of locally monitored lakes.
Lake Beulah is on the Wisconsin infested-waters list for zebra mussels — boaters should follow clean-drain-dry protocols when moving gear to or from the lake. Bass fishing is part of the appeal: the species list runs to 3, anchored by largemouth and/or smallmouth bass. A documented public access point at Lake Beulah makes the lake usable for shore fishing, paddle craft, and trailered boats. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2022-11-02. Grade methodology: LakeGrade methodology.
Watch Lake Beulah water quality
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Swimming Safety
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A, Excellent
Good clarity, visible to about 11 ft. Phosphorus level: 13 µg/L. Trophic State Index: 42.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 11 ft | B |
| Phosphorus | 13 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 | 58 ft |
| Surface Area | 812 acres |
| Public Access | Yes |
Fish Species
Click a species to see every graded lake where it is documented.
→ Best fishing times for Lake Beulah (14-day solunar calendar)
→ Is it safe to eat fish from Lake Beulah? (mercury & PFAS guide)
→ Lake Beulah 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: ↑ Improving
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.4 m/yr | 6 |
| Phosphorus | ↑ Improving | -0.49 µg/L/yr | 6 |
Recreation & Access
Location
County Ranking
Ranked #5 of 35 lakes in Walworth County
Nearby Lakes in Walworth County
More Wisconsin Lake Rankings
State Parks Near Lake Beulah
Other Grade A Lakes in Wisconsin
Washington County · Clarity: 11.8 ft
Washington County · Clarity: 12.6 ft
Waukesha County · Clarity: 11.3 ft
Kenosha County · Clarity: 10 ft
Sawyer County · Clarity: 12.2 ft
Waukesha County · Clarity: 10 ft
Mesotrophic Lakes in Wisconsin
Compare Lake Beulah With Nearby Lakes
WI DNR Lake Profile
Authoritative data from the Wisconsin DNR LakePages. Monitored by volunteers since 1991. 7 stations on file (most recent sample 2026).
Fish Species (DNR-rated)
Reservoir Info (USACE NID)
Lake Beulah is a man-made reservoir impounded by the Lake Beulah (completed 1840), built primarily for recreation on the Lake Beulah Outlet; gravity-type dam, 14 ft tall and 300 ft long.
- Surface area
- 834 ac
- Normal storage
- 5,000 ac-ft
- Max storage
- 7,000 ac-ft
- Drainage area
- 10 sq mi
- Hazard class
- High
- Owner
- Lake Beulah Management District;Walworth County
Source: USACE National Inventory of Dams, NID ID WI00699 · Operator website
EPA Impairment Status
Lake Beulah 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 WI10000591 · Official waterbody report
Data Sources
Water quality data from the EPA Water Quality Portal
Impairment status from EPA ATTAINS 303(d) database
Grading methodology based on Metropolitan Council standards
Fish and recreation data from Wisconsin DNR Lakes
Public boat-access points from the USGS National Boat Ramps inventory
Most recent sample: 2022-11-02
Monitoring stations: 1
Where to stay near Lake Beulah
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