Jones Slough Lake
Jones Slough Lake in Grant County, Wisconsin has a water quality grade of C (Fair). Water clarity: 4.9 ft visibility. Phosphorus: 31 µg/L.
- Clarity
- 4.9 ft
- Type
- Eutrophic
- Trend
- ↓ Declining
- Public access
- Yes
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Jones Slough Lake is a productive, nutrient-rich eutrophic lake in Grant County, Wisconsin. Water quality is graded C based on 1 sampling years through 2023. Overall water quality is declining over recent sampling years. Limited fish-species data available. Public access is available with 1 public boat landing. Compared to the 2 other monitored lakes in Grant County, Jones Slough Lake ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2023-10-30. Grade methodology: LakeQuality methodology.
Watch Jones Slough Lake water quality
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Swimming Safety
Grade onlyLimited data
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.
Generally safe for swimming, moderate water quality
Water Quality Grade: C (Fair)
Murky, only visible to about 4.9 ft. Phosphorus level: 31 µg/L. Trophic State Index: 54.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 4.9 ft | Not graded |
| Phosphorus | 31 µg/L | Fair |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 54 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Jones Slough Lake
Compare lakeside cabins, hotels, and vacation rentals near Jones Slough Lake in Grant 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 Jones Slough Lake
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Recreation & Access
- Port AndrewsPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Fishing Jones Slough Lake
Water Quality Trend: ↓ Declining
Based on 2 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.3 m/yr | 2 |
| Phosphorus | ↓ Declining | +35.6 µg/L/yr | 2 |
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Jones Slough Lake under Clean Water Act (NPDES) discharge permits. 1 facility has a reported Clean Water Act violation in the past three years.
- Blue River Wastewater Treatment FacilityBlue River · 1.4 mi away · NPDES WI0023418Recent 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 #1 of 3 lakes in Grant County
Nearby Lakes With Higher Grades
Jones Slough Lake holds Grade C. One nearby lake has a higher nutrient-and-algae grade — useful for a swim day, not a reason to skip lodging here.
Nearby Lakes in Grant County
Frequently asked questions about Jones Slough Lake
Where is Jones Slough Lake?
- Jones Slough Lake is a lake in Grant County, Wisconsin. LakeQuality grades it C for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Jones Slough Lake?
- Jones Slough Lake in Grant County, Wisconsin has a water quality grade of C (Fair). Water clarity: 4.9 ft visibility. Phosphorus: 31 µg/L.
Is Jones Slough Lake safe to swim in?
- Generally safe for swimming, moderate water quality. Jones Slough Lake has a water quality grade of C (Fair). Always check local health department advisories before swimming.
Are there boat ramps on Jones Slough Lake?
- Jones Slough Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Port Andrews. Public access is listed as yes.
Explore Jones Slough Lake across LakeQuality
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Species activity outlook by water temperature and season
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High nutrients, frequent algae, reduced clarity
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Other Grade C Lakes in Wisconsin
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Where this data comes from
12 measurements from 1 monitoring station, 2023. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX12 samples · 2023
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
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Fish and recreation data from Wisconsin DNR Lakes
Named boat-access points from the USGS National Boat Ramps inventory