Is Lake Delton, WI Tap Water Safe to Drink?
Graded A-, with 5 unresolved violations on record. See what was cited — and what it means for your tap. What to do next ↓
86.7/100
waterverge.com Lake Delton, WI — Water Quality Report
Lake Delton's drinking water received a grade of A- (86.7 out of 100), indicating good water quality. The city's 3 water systems serve approximately 3,295 residents using groundwater.
Lead levels were measured at 2.1 ppb (90th percentile), well within EPA limits. This system has not yet been tested for PFAS under the EPA UCMR 5 program.
The system has 14 violations on record, including 2 health-based violations. 5 remain unresolved.
What to know about Lake Delton's water
Lake Delton ranks #141 out of 446 cities in Wisconsin for water quality, placing it mid-range in the state.
Lake Delton relies on groundwater, which is generally less vulnerable to surface contamination but can be affected by naturally occurring minerals like arsenic and nitrate, as well as agricultural and industrial runoff.
As a small community water system, Lake Delton may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
Water quality score
See methodology →Is Lake Delton, WI water safe to drink?
Lake Delton's drinking water has significant quality concerns based on EPA testing data. With a grade of A- (86.7/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 3 water systems serve approximately 3,295 residents using groundwater (wells).
Recent water quality updates for Lake Delton
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Lake Delton's water quality assessment. Grade: A- (86.7/100).
Contaminants: Consumer Confidence Rule.
Federal disaster declaration (FEMA DR-4402). Flood event — may have impacted local water infrastructure.
Contaminants: Combined Uranium, Radium-228, Combined Radium (-226 and -228).
Federal disaster declaration (FEMA DR-3249). Hurricane event — may have impacted local water infrastructure.
Contaminants: Coliform (TCR).
Key contaminant findings
Based on the most recent EPA sampling data for Lake Delton's water supply.
Well within EPA limits.
Violation history
Lake Delton's water system has 14 total violations on record, including 2 health-based violations. 5 remain unresolved. 2 violations were issued in the last 5 years.
Flood & environmental risk
Sauk County has experienced 4 federally declared disasters since 1976. Flooding and severe storms can overwhelm water treatment plants, cause sewage overflows, and introduce agricultural runoff, bacteria, and sediment into drinking water supplies. Local water sources include Wisconsin River.
Where does Lake Delton's water come from?
Lake Delton's drinking water comes from groundwater (wells), supplied by 3 water systems serving approximately 3,295 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate. Nearby water bodies include Wisconsin River (river).
What Lake Delton residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in Lake Delton's water.
Your water utility is required to publish an annual Consumer Confidence Report (CCR) with detailed testing results. Ask for the latest copy or check your utility's website.
Lake Delton's area has a history of flooding. After severe weather, watch for boil water advisories from your local utility.
Data: EPA SDWIS, UCMR 5 (PFAS), FEMA, NOAA. Last updated May 2026.
Top contaminants to know
View all ↓Violation summary
Violations & advisories
Top industrial polluters within 10 miles of Lake Delton
Industrial polluters nearby
Reported releases to surface water by facilities near Lake Delton, ranked by pounds discharged annually.
| Facility | Top chemical | To surface water (lbs/yr) | Distance |
|---|---|---|---|
SENECA FOODS CORP BARABOO, WI53913 | — | — | 9.1 mi |
TEEL PIPE LLC BARABOO, WI53913 | — | — | 8.8 mi |
Source: EPA Toxic Release Inventory (TRI) 2023
Superfund sites within 10 miles of Lake Delton
Superfund sites nearby
Federally tracked hazardous-waste sites on the EPA National Priorities List. Proximity does not necessarily indicate tap-water contamination — the connection depends on hydrology and treatment.
- SAUK COUNTY LANDFILL7.1 mi
Source: EPA Superfund National Priorities List
Flood & disaster history
Sauk County has experienced 4 federally declared disasters since 1976. Flooding and severe weather can compromise water treatment infrastructure and introduce contaminants into drinking water supplies.
Full contaminants report
| Contaminant | Detected Level | EPA Limit | Unit | Category | Status |
|---|---|---|---|---|---|
| Lead (90th percentile) LeadHeavy Metal A toxic heavy metal that can leach into drinking water from older pipes, solder, and fixtures. No amount of lead in water is considered safe. Health EffectsBrain and nervous system damage in children, kidney damage, high blood pressure, and reproductive problems in adults. EPA Limit15 ppb action level Common SourcesCorrosion of lead pipes, lead solder, brass faucets, and household plumbing. | 2.1 | 15 | ppb | Inorganic | Safe |
Lead level trend (90th percentile)
See how Lake Delton compares by contaminant
Explore where Lake Delton ranks among all Wisconsin cities for specific contaminants.
Water source & infrastructure
Where Lake Delton's water comes from
Lake Delton's drinking water is drawn from underground aquifers through wells.
Groundwater is naturally filtered through rock and soil layers, generally requiring less treatment than surface water. However, it can contain naturally occurring contaminants like arsenic, radon, and minerals.
Agricultural activity, septic systems, and industrial operations near well fields can introduce nitrates, pesticides, and volatile organic compounds.
The system is operated by local government ownership and serves approximately 3,295 people through 3 water systems.
Water bodies near Lake Delton
Lake Delton is located near 1 notable water body. These water bodies contribute to the regional watershed and may indirectly affect groundwater quality.
Water systems serving Lake Delton
| System Name | PWSID | Population | Source |
|---|---|---|---|
| LAKE DELTON WATERWORKS | WI1570664 | 2,914 | GW |
| IRH BIG CEDAR | MO5066376 | 306 | GW |
| LOWER DELLS MHC | WI1570086 | 75 | GW |
How Lake Delton compares
Full Wisconsin rankings →Lake Delton's score of 86.7/100 is above the average of 65/100 among major Wisconsin cities. It outscores 8 of 10 nearby cities.
Nearby cities
View Wisconsin rankings →About Lake Delton, WI
Wikipedia →Lake Delton is a village in Sauk County, Wisconsin, United States. The population was 3,501 at the 2020 census. Located on the Wisconsin River and Lake Delton reservoir, the village forms a resort area and tourism destination along with nearby Wisconsin Dells. Lake Delton is included in the Baraboo micropolitan area about 40 miles (64 km) northwest of the state capital, Madison.
Learn more about your water
Guides and resources related to Lake Delton's water quality findings.
Explore water quality across Sauk
Frequently asked questions
Is Lake Delton, WI tap water safe to drink?
Lake Delton's water quality earned a grade of A- (86.7/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #141 out of 446 cities tested in Wisconsin.
What contaminants are in Lake Delton's water?
Lead was measured at 2.1 ppb (90th percentile). 14 violations are on record.
How is Lake Delton's water quality grade calculated?
The grade is based on four factors: violation history (40%), lead and copper levels (25%), PFAS contamination (25%), and regulatory compliance (10%). The score is also adjusted based on how complete the available data is. See our methodology page for full details.
Do I need a water filter in Lake Delton?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Lake Delton's water come from?
Lake Delton's water is sourced from Groundwater. The city has 3 water systems serving approximately 3,295 residents.
What health violations has Lake Delton's water system had?
Lake Delton has 2 health-based violations on record. The most recent violation was recorded in July 2025. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 5 violations remain unresolved.
Is Lake Delton's groundwater at risk of contamination?
Lake Delton uses groundwater, which can be affected by naturally occurring contaminants like arsenic, radon, and nitrate, as well as agricultural runoff and industrial activity. The system has 14 violations on record that may relate to groundwater quality. Groundwater systems are generally less susceptible to surface contamination but should be monitored for emerging contaminants like PFAS.
How does Lake Delton's water compare to other cities?
Lake Delton ranks #141 out of 446 cities in Wisconsin (better than 68% of state cities) and #4514 out of 15744 cities nationally (71th percentile). The grade of A- reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.