Is Johnson Creek, WI Tap Water Safe to Drink?
Graded C, with 28 unresolved violations on record. See what was cited — and what it means for your tap. What to do next ↓
61.6/100
waterverge.com Johnson Creek, WI — Water Quality Report
Johnson Creek's drinking water received a grade of C (61.6 out of 100), indicating fair water quality. The city's 2 water systems serve approximately 3,348 residents using groundwater.
Lead levels were measured at 0.8 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 66 violations on record, including 7 health-based violations. 28 remain unresolved.
What to know about Johnson Creek's water
Johnson Creek ranks #381 out of 446 cities in Wisconsin for water quality, placing it among the lowest-rated in the state.
Johnson Creek 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.
The system has seen 18 violations in the past five years, suggesting a pattern of compliance challenges that residents should monitor closely.
Water quality score
See methodology →Is Johnson Creek, WI water safe to drink?
Johnson Creek's drinking water has significant quality concerns based on EPA testing data. With a grade of C (61.6/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 2 water systems serve approximately 3,348 residents using groundwater (wells).
Recent water quality updates for Johnson Creek
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Johnson Creek's water quality assessment. Grade: C (61.6/100).
Contaminants: Lead and Copper Rule.
Contaminants: Public Notice.
Contaminants: Revised Total Coliform Rule.
Federal disaster declaration (FEMA DR-3249). Hurricane event — may have impacted local water infrastructure.
Federal disaster declaration (FEMA DR-496). Flood event — may have impacted local water infrastructure.
Key contaminant findings
Based on the most recent EPA sampling data for Johnson Creek's water supply.
Well within EPA limits.
Violation history
Johnson Creek's water system has 66 total violations on record, including 7 health-based violations. 28 remain unresolved. 18 violations were issued in the last 5 years.
Flood & environmental risk
Jefferson County has experienced 3 federally declared disasters since 1973. 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 Rock River, Crawfish River, Bark River.
Where does Johnson Creek's water come from?
Johnson Creek's drinking water comes from groundwater (wells), supplied by 2 water systems serving approximately 3,348 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate. Nearby water bodies include Rock River (river), Crawfish River (river), Bark River (river).
What Johnson Creek residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in Johnson Creek'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.
Johnson Creek'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 Johnson Creek
Industrial polluters nearby
Reported releases to surface water by facilities near Johnson Creek, ranked by pounds discharged annually.
Total reported releases to surface water: 0 lbs
| Facility | Top chemical | To surface water (lbs/yr) | Distance |
|---|---|---|---|
WISCONSIN INVESTCAST WATERTOWN, WI53094 | Nickel | 0 | 7.7 mi |
MILKRITE INTERPULS INC JOHNSON CREEK, WI53038 | — | — | 0.2 mi |
MASTERMOLD LLC JOHNSON CREEK, WI53038 | — | — | 0.2 mi |
AZTALAN BIO JOHNSON CREEK, WI53038 | — | — | 0.4 mi |
FISHER-BARTON SPECIALTY PRODUCTS WATERTOWN, WI53094 | — | — | 7.0 mi |
Source: EPA Toxic Release Inventory (TRI) 2023
Flood & disaster history
Jefferson County has experienced 3 federally declared disasters since 1973. 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. | 0.8 | 15 | ppb | Inorganic | Safe |
Lead level trend (90th percentile)
See how Johnson Creek compares by contaminant
Explore where Johnson Creek ranks among all Wisconsin cities for specific contaminants.
Water source & infrastructure
Where Johnson Creek's water comes from
Johnson Creek'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 3,348 people through 2 water systems.
Water bodies near Johnson Creek
Johnson Creek is located near 3 notable water bodies. These water bodies contribute to the regional watershed and may indirectly affect groundwater quality.
Water systems serving Johnson Creek
| System Name | PWSID | Population | Source |
|---|---|---|---|
| JOHNSON CREEK WATERWORKS | WI1280107 | 3,318 | GW |
| ROCK RIVER MOBILE HOME PARK | WI1280106 | 30 | GW |
How Johnson Creek compares
Full Wisconsin rankings →Johnson Creek's score of 61.6/100 is on par with the average of 65/100 among major Wisconsin cities. It outscores 5 of 10 nearby cities.
Nearby cities
View Wisconsin rankings →About Johnson Creek, WI
Learn more about your water
Guides and resources related to Johnson Creek's water quality findings.
Explore water quality across Jefferson
Frequently asked questions
Is Johnson Creek, WI tap water safe to drink?
Johnson Creek's water quality earned a grade of C (61.6/100). Some concerns have been identified. Consider a water filter for an extra layer of protection. The city ranks #381 out of 446 cities tested in Wisconsin.
What contaminants are in Johnson Creek's water?
Lead was measured at 0.8 ppb (90th percentile). 66 violations are on record.
How is Johnson Creek'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 Johnson Creek?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Johnson Creek's water come from?
Johnson Creek's water is sourced from Groundwater. The city has 2 water systems serving approximately 3,348 residents.
What health violations has Johnson Creek's water system had?
Johnson Creek has 7 health-based violations on record. The most recent violation was recorded in January 2025. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 28 violations remain unresolved.
Is Johnson Creek's groundwater at risk of contamination?
Johnson Creek 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 66 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 Johnson Creek's water compare to other cities?
Johnson Creek ranks #381 out of 446 cities in Wisconsin (better than 15% of state cities) and #11970 out of 15744 cities nationally (24th percentile). The grade of C reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.