Lake Delton
Lake Delton in Sauk County, Wisconsin is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 2.5 ft visibility. Maximum depth: 16 ft. Surface area: 249 acres.
Wisconsin DNR lists Largemouth Bass as common on Lake Delton. DNR survey details →
- Clarity
- 2.5 ft
- Typical in August
- 75°F
- Max depth
- 16 ft
- Area
- 249 acres
- Trend
- ↓ Declining
- Public access
- Yes
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Why Lake Delton has no grade
We grade a lake only when the monitoring record supports a letter: at least three phosphorus or chlorophyll-a samples in the last ten years, scored against EPA National Lakes Assessment thresholds for this lake’s ecoregion. For Lake Delton, the only measurement available is water clarity, which is not a water-quality indicator on its own — EPA's National Lakes Assessment does not grade clarity. Sampling here has recorded water clarity, but not phosphorus and algae (chlorophyll-a).
Not Rated is not an F. It is EPA Integrated Reporting Category 3 — insufficient information. The water here may be excellent or poor; nobody has measured enough of it to say. Everything below that has been measured is still reported on this page.
Sampling is run by WI DNR and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
Lake Delton is a 249-acre lake in Sauk County, Wisconsin with a maximum depth of 16 feet. Overall water quality is declining over recent sampling years. The lake supports 5 documented fish species including Panfish, Largemouth Bass, and Northern Pike. Public access is available with 5 public boat landings.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2024-10-10. Grade methodology: LakeQuality methodology.
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Swimming Safety
Not ratedLimited data
Not rated for swimming — there is not enough monitoring data to judge this lake
Water quality measurements for Lake Delton
These readings exist but are not enough for an A–F grade — see why.
Very murky, less than 2.5 ft of visibility. Trophic State Index: 64.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 2.5 ft | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 64 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Lake Delton
Compare lakeside cabins, hotels, and vacation rentals near Lake Delton in Sauk 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 Lake Delton
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Planning a whole trip? See where to stay at Wisconsin’s top lakes →
Water Temperature
Lake Delton typically sits around 75°F at the surface in August. Summer average is about 74°F. Usually warmest in Jul (about 76°F) and coldest in Oct (about 63°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 19 field readings (2024–2024) via the EPA Water Quality Portal. See the full Lake Delton water temperature breakdown →
Wisconsin DNR lists Largemouth Bass as common on Lake Delton.
A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality does not assign an A–F grade on Lake Delton — official chemistry is on file, not a letter, and the water-quality trend over 4 years of monitoring is declining. 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. 3 stations on file (most recent sample 2024).
Fish Species (DNR-rated)
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 16 ft |
| Surface Area | 249 acres |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Norway DrivePublic
- Canyon RoadPublic
- Indian TrailPublic
- Wisconsin Dells - Crandalls BayPublic
- Newport ParkPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Lake Delton
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 4 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.089 m/yr | 4 |
Reservoir Info (USACE NID)
Lake Delton is a man-made reservoir impounded by the Dell Creek (completed 1927), built primarily for recreation on the Dell Creek; gravity-type dam, 30 ft tall and 400 ft long.
- Surface area
- 267 ac
- Normal storage
- 1,420 ac-ft
- Max storage
- 2,500 ac-ft
- Drainage area
- 80 sq mi
- Hazard class
- Low
- Owner
- Village Of Lake Delton
Source: USACE National Inventory of Dams, NID ID WI00055 · Operator website
EPA Impairment Status
Lake Delton is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit WI10002737 · Official waterbody report
Regulated Pollution Sources Nearby
2 EPA-permitted facilities operate within about 5 miles of Lake Delton 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.
- Wi Dells Lake Delton Sew CommLake Delton · 0.9 mi away · NPDES WI0031402MajorRecent violation
- Chula Vista CheeseWisconsin Dells · 1.9 mi away · NPDES WI0053244
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.
Graded lakes near Lake Delton
Lake Delton has no grade, but these lakes within a short drive do.
Nearby Lakes in Sauk County
Frequently asked questions about Lake Delton
Where is Lake Delton?
- Lake Delton is a lake in Sauk County, Wisconsin. LakeQuality has not rated this lake (UNRATED) — there is not enough recent sampling to assign a letter.
What is the water quality grade for Lake Delton?
- Lake Delton in Sauk County, Wisconsin is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 2.5 ft visibility. Maximum depth: 16 ft. Surface area: 249 acres.
Is Lake Delton safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Lake Delton is not rated for water quality — its monitoring record does not meet the evidence bar. Always check local health department advisories before swimming.
What is the water temperature of Lake Delton?
- Lake Delton typically sits around 75°F at the surface in August, from 19 EPA Water Quality Portal field readings (2024–2024). That is a typical value for the month, not a live reading.
How deep is Lake Delton?
- Lake Delton has a maximum depth of 16 feet. The lake covers 249 acres.
What fish are in Lake Delton?
- Fish species found in Lake Delton include Panfish, Largemouth Bass, Northern Pike, Walleye, Catfish. Lake Delton is located in Sauk County, Wisconsin.
What did the DNR fisheries survey find at Lake Delton?
- Wisconsin DNR lists Largemouth Bass as common on Lake Delton. A DNR fisheries survey reports fish abundance and catch rates, not a water-quality grade. LakeQuality does not assign an A–F grade on Lake Delton — official chemistry is on file, not a letter, and the water-quality trend over 4 years of monitoring is declining. Catch rate is not a swim clearance and is not a weekly bite report.
Are there boat ramps on Lake Delton?
- Lake Delton has 5 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Norway Drive, Canyon Road, Indian Trail, Wisconsin Dells - Crandalls Bay, among others. Public access is listed as yes.
Explore Lake Delton 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 Sauk County
Species activity outlook by water temperature and season
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State Parks Near Lake Delton
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Where this data comes from
49 measurements from 1 monitoring station, 2021–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX49 samples · 2021–2024
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