Big Cedar Lake
Washington County, WisconsinMesotrophic
Big Cedar Lake comes in at a B on the grading rubric — a respectable showing for a Wisconsin lake of its size and depth. The lake's weakest score is on Secchi depth — the water looks more turbid than its phosphorus number alone would predict.
A TSI near 44 places Big Cedar Lake in the mesotrophic band — moderate productivity, with seasonal swings between clearer spring water and richer late-summer conditions. Big Cedar Lake is unusually deep for Wisconsin at 105 ft, which buffers the lake against summer warming and helps the deep water stay oxygenated. The lake's 937 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. Big Cedar Lake sits at rank 9 of 15 in Washington County, in the lower half of the local distribution.
Big Cedar Lake 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. The fishery includes walleye alongside the lake's other 4 documented species — a notable draw for Wisconsin anglers. Public access is available — the lake is on the Wisconsin DNR public-access list. 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 2026-04-20. Grade methodology: LakeGrade methodology.
Watch Big Cedar Lake water quality
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Swimming Safety
Good for swimming, clear water with low algae levels
Water Quality Grade: B, Good
Moderate clarity, visible to about 9.8 ft. Phosphorus level: 15.5 µg/L. Trophic State Index: 44.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 9.8 ft | C |
| Phosphorus | 15.5 µg/L | A |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 44 | Mesotrophic |
Moderate nutrients, good water quality
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 105 ft |
| Surface Area | 937 acres |
| Public Access | Yes |
Fish Species
Click a species to see every graded lake where it is documented.
→ Best fishing times for Big Cedar Lake (14-day solunar calendar)
→ Is it safe to eat fish from Big Cedar Lake? (mercury & PFAS guide)
→ Big Cedar Lake 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 | +0.379 m/yr | 6 |
| Phosphorus | ↑ Improving | -1.06 µg/L/yr | 6 |
Recreation & Access
Location
County Ranking
Ranked #9 of 15 lakes in Washington County
Cleaner Lakes Within 30 Miles
Big Cedar Lake holds Grade B. 4 nearby lakes hold higher grades.
- ABig Cedar LakeWashington County · mi · Higher grade (B → A)
- ABig Cedar Lake-South Site-Near West BendWashington County · mi · Higher grade (B → A)
- ALittle Cedar LakeWashington County · mi · Higher grade (B → A)
- ABig Cedar Lake-North Site-Near West BendWashington County · mi · Higher grade (B → A)
Nearby Lakes in Washington County
More Wisconsin Lake Rankings
State Parks Near Big Cedar Lake
Other Grade B Lakes in Wisconsin
Mesotrophic Lakes in Wisconsin
Compare Big Cedar Lake With Nearby Lakes
Washington County · Grade A
Washington County · Grade A
Washington County · Grade A
Washington County · Grade B
WI DNR Lake Profile
Authoritative data from the Wisconsin DNR LakePages. 3 stations on file (most recent sample 2025).
Fish Species (DNR-rated)
EPA Impairment Status
Big Cedar 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 WI10008013 · Official waterbody report · Matched by proximity (2.78 km)
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: 2026-04-20
Monitoring stations: 1
Where to stay near Big Cedar Lake
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