Lake Delton
Sauk County, Wisconsin249 acresView mapDirections
Wisconsin DNR publishes the water-quality measurements for Lake Delton. Here is what has been measured.
- Impaired · Nutrients (phosphorus, nitrogen)
- 3 aquatic invasives
- 16 ft max depth
- Public access
- Limited data
Lake Delton in Sauk County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. 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 →
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 2 public boat landings.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2024-10-10. Methodology: how these readings are compared.
Lake Delton covers about 250 acres in Sauk County. It has 2 public boat landings, so a lakefront rental is not the only way to get a boat on the water. For a place on the water, look through cabin and lake-house rentals near Lake Delton on Vrbo. For a hotel or motel room, Booking.com and Expedia both search around the lake.
What Lake Delton is good for
From access and monitoring records, not editorial picks.
- Boat launch2 documented ramps
- Fishing5 species recorded
Swimming conditions
No readingRecreation use not supported
Nutrient and algae readings are not a swimming clearance. Lake Delton is listed impaired under Clean Water Act §303(d) (IR 4A) for nutrients (phosphorus, nitrogen). Check local advisories before you swim.
Whether Lake Delton is safe to swim in today is a call for the Wisconsin Department of Natural Resources and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Lake Delton
These are the measurements Wisconsin DNR publishes for Lake Delton, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Very murky, less than 2.5 ft of visibility. TSI 64.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 2.5ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | No reading The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. | |
| Chlorophyll-a (algae) | No reading The green pigment in algae — a direct measure of how much algae is in the water. | |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 64 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Lake Delton
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Lake Delton typically sits around 63°F at the surface in October. 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.
Column height runs from this lake’s coldest month (63°F) to its warmest (76°F).
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 water quality. LakeQuality shows Lake Delton’s water-quality measurements separately, 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
Max depth
16 ft
Surface area
249 acres
Public access
Yes
Listed by Wisconsin DNR
Lake Size & Watershed
Watershed (drainage) area
75 sq mi
HydroLAKES / HydroSHEDS
Shoreline
4.1 mi
HydroLAKES / HydroSHEDS
Elevation
830 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Canyon RoadPublic
- Newport ParkPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays 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
Prices for Oct 9–11, 4 adults. Change dates on the map below.
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
Planning a whole trip? See where to stay at Wisconsin’s top lakes →
Follow Lake Delton’s readings
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Fish Species
Click a species to see every 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: Worsening
Based on 4 years of monitoring (2021–2024).
Water clarity
Worsening4 years
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
Designated uses not supporting: Aquatic life, Recreation.
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.
Nearby Lakes in Sauk County
Frequently asked questions about Lake Delton
Where is Lake Delton?
- Lake Delton is a lake in Sauk County, Wisconsin. Its water-quality measurements are published by Wisconsin DNR and shown on this page as reported.
What is the water quality of Lake Delton?
- Lake Delton in Sauk County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 2.5 ft visibility. Maximum depth: 16 ft. Surface area: 249 acres.
Is Lake Delton safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Lake Delton is listed impaired under Clean Water Act §303(d) (IR 4A) for nutrients (phosphorus, nitrogen). Check local advisories before you swim.
What is the water temperature of Lake Delton?
- Lake Delton typically sits around 63°F at the surface in October, 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 water quality. LakeQuality shows Lake Delton’s water-quality measurements separately, 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 2 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Canyon Road, Newport Park. Public access is listed as yes.
Can I fish at Lake Delton?
- Lake Delton has 2 documented boat landings in the USGS National Boat Ramps inventory. Seasons, size and bag limits, and whether you need a license are set by Wisconsin's fish and wildlife agency, so check its current regulations before you go.
Explore Lake Delton across LakeQuality
Depth, room, public access, and the state wake-sport rules
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Species activity outlook by water temperature and season
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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)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from 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