Lower Phantom Lake
Lower Phantom Lake in Waukesha County, Wisconsin has a water quality grade of B (Good). Water clarity: 6.7 ft visibility. Phosphorus: 15.7 µg/L. Maximum depth: 12 ft. Surface area: 373 acres.
Wisconsin DNR lists Largemouth Bass as common on Lower Phantom Lake. DNR survey details →
- Clarity
- 6.7 ft
- Max depth
- 12 ft
- Area
- 373 acres
- Type
- Mesotrophic
- Trend
- ↑ Improving
- Public access
- Yes
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Lower Phantom Lake is a 373-acre mesotrophic lake in Waukesha County, Wisconsin with a maximum depth of 12 feet. Water quality is graded B based on 1 sampling years through 2026. Overall water quality is improving over recent sampling years. The lake supports 3 documented fish species including Panfish, Largemouth Bass, and Northern Pike. Public access is available with 1 public boat landing. Compared to the 34 other monitored lakes in Waukesha County, Lower Phantom Lake ranks #30 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-03-30. Grade methodology: LakeQuality methodology.
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Swimming Safety
Grade onlyLow algae
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.
Good for swimming, clear water with low algae levels
Water Quality Grade: B (Good)
Moderate clarity, visible to about 6.7 ft. Phosphorus level: 15.7 µg/L. Trophic State Index: 47.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 6.7 ft | Not graded |
| Phosphorus | 15.7 µg/L | Good |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 47 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Lower Phantom Lake
Compare lakeside cabins, hotels, and vacation rentals near Lower Phantom Lake in Waukesha 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.
Top-rated places to stay near Lower Phantom Lake
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Wisconsin DNR lists Largemouth Bass as common on Lower Phantom Lake.
A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades Lower Phantom Lake B from EPA Water Quality Portal chemistry, and the water-quality trend over 6 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
WI DNR Lake Profile
Authoritative data from the Wisconsin DNR LakePages. 1 station on file (most recent sample 2026).
Fish Species (DNR-rated)
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 12 ft |
| Surface Area | 373 acres |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Lower Phantom LakePublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Public campgrounds near Lower Phantom Lake
- Mukwonago Park Campground3.6 km
Nearest public campgrounds in the USGS National Map inventory, within about 3 miles. An empty list means USGS records no campground that close, which is not the same as camping being unavailable. Where the source gives an official reservation link, it is used; the cabin and hotel search does not cover campsites. More camping lakes
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Lower Phantom Lake
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 | +0.275 m/yr | 6 |
| Phosphorus | → Stable | -0.22 µg/L/yr | 6 |
Reservoir Info (USACE NID)
Lower Phantom Lake is a man-made reservoir impounded by the Mukwonago (completed 1848), built primarily for recreation on the MUKWONAGO; gravity-type dam, 10 ft tall and 250 ft long.
- Surface area
- 540 ac
- Normal storage
- 2,200 ac-ft
- Max storage
- 2,740 ac-ft
- Drainage area
- 60 sq mi
- Hazard class
- Low
- Owner
- Village Of Mukwonago
Source: USACE National Inventory of Dams, NID ID WI00334 · Operator website · Matched by proximity (0.79 km)
EPA Impairment Status
Lower Phantom 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 WI10000590 · Official waterbody report · Matched by proximity (1.25 km)
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Lower Phantom Lake under Clean Water Act (NPDES) discharge permits, including 1 classified by the EPA as major discharger. 1 facility has a reported Clean Water Act violation in the past three years.
- Mukwonago Wastewater Treatment PlantMukwonago · 1.3 mi away · NPDES WI0020265MajorRecent violation
Facilities permitted to discharge under the Clean Water Act within ~5 miles; proximity does not by itself mean a facility affects this lake. Source: EPA ECHO (ICIS-NPDES), as of 2026-07.
County Ranking
Ranked #30 of 35 lakes in Waukesha County
Nearby Lakes With Higher Grades
Lower Phantom Lake holds Grade B. 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 Waukesha County
Frequently asked questions about Lower Phantom Lake
Where is Lower Phantom Lake?
- Lower Phantom Lake is a lake in Waukesha County, Wisconsin. LakeQuality grades it B for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Lower Phantom Lake?
- Lower Phantom Lake in Waukesha County, Wisconsin has a water quality grade of B (Good). Water clarity: 6.7 ft visibility. Phosphorus: 15.7 µg/L. Maximum depth: 12 ft. Surface area: 373 acres.
Is Lower Phantom Lake safe to swim in?
- Good for swimming, clear water with low algae levels. Lower Phantom Lake has a water quality grade of B (Good). Always check local health department advisories before swimming.
How deep is Lower Phantom Lake?
- Lower Phantom Lake has a maximum depth of 12 feet. The lake covers 373 acres.
What fish are in Lower Phantom Lake?
- Fish species found in Lower Phantom Lake include Panfish, Largemouth Bass, Northern Pike. Lower Phantom Lake is located in Waukesha County, Wisconsin.
What did the DNR fisheries survey find at Lower Phantom Lake?
- Wisconsin DNR lists Largemouth Bass as common on Lower Phantom Lake. A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality grades Lower Phantom Lake B from EPA Water Quality Portal chemistry, and the water-quality trend over 6 years of monitoring is improving. Catch rate is not a swim clearance and is not a weekly bite report.
Are there boat ramps on Lower Phantom Lake?
- Lower Phantom Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Lower Phantom Lake. Public access is listed as yes.
Are there campgrounds on Lower Phantom Lake?
- Lower Phantom Lake has 1 public campground from USGS The National Map within 5 km, including Mukwonago Park Campground. This is a location join, not a booking. Cabins and hotels are listed separately; campsite reservations use the official link when the source provides one.
Explore Lower Phantom Lake across LakeQuality
Depth, room, public access, and the state wake-sport rules
Fish species and top-graded lakes across Wisconsin
Fish species and best lakes in Waukesha County
Species activity outlook by water temperature and season
Where to stay at Wisconsin's top lakes, each with its grade
Moderate nutrients, good water quality
Wisconsin's cleanest and most-polluted lakes, ranked
More Wisconsin Lake Rankings
State Parks Near Lower Phantom Lake
Other Grade B Lakes in Wisconsin
Mesotrophic Lakes in Wisconsin
Where this data comes from
47 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_WQX47 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
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Lake size & watershed from HydroLAKES (HydroSHEDS)
Fish and recreation data from Wisconsin DNR Lakes
Named boat-access points from the USGS National Boat Ramps inventory
Public campgrounds from USGS The National Map Structures, within about 3 miles