Is Hillsboro, WI Tap Water Safe to Drink?
Graded C+ — but Copper was detected above EPA limits. Here's what's in the water and how to remove it. What to do next ↓
66/100
waterverge.com Hillsboro, WI — Water Quality Report
Hillsboro's drinking water received a grade of C+ (66 out of 100), indicating fair water quality. The city's 2 water systems serve approximately 1,385 residents using groundwater.
Lead levels were measured at 3.2 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 53 violations on record, including 13 health-based violations. 21 remain unresolved.
What to know about Hillsboro's water
Hillsboro ranks #369 out of 446 cities in Wisconsin for water quality, placing it among the lowest-rated in the state.
Hillsboro 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, Hillsboro may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
Water quality score
See methodology →Is Hillsboro, WI water safe to drink?
Hillsboro's drinking water has significant quality concerns based on EPA testing data. With a grade of C+ (66/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 2 water systems serve approximately 1,385 residents using groundwater (wells).
Recent water quality updates for Hillsboro
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Hillsboro's water quality assessment. Grade: C+ (66/100).
Contaminants: Consumer Confidence Rule.
1 health-based. Contaminants: Lead and Copper Rule.
1 health-based. Contaminants: Lead and Copper Rule.
Federal disaster declaration (FEMA DR-4459). Flood event — may have impacted local water infrastructure.
Federal disaster declaration (FEMA DR-4402). Flood event — may have impacted local water infrastructure.
Key contaminant findings
Based on the most recent EPA sampling data for Hillsboro's water supply.
Well within EPA limits.
Exceeds EPA action level. Copper can leach from household plumbing — flush taps for 30 seconds before drinking.
Violation history
Hillsboro's water system has 53 total violations on record, including 13 health-based violations. 21 remain unresolved. 4 violations were issued in the last 5 years.
Flood & environmental risk
Vernon County has experienced 8 federally declared disasters since 1969. Flooding and severe storms can overwhelm water treatment plants, cause sewage overflows, and introduce agricultural runoff, bacteria, and sediment into drinking water supplies.
Where does Hillsboro's water come from?
Hillsboro's drinking water comes from groundwater (wells), supplied by 2 water systems serving approximately 1,385 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate.
What Hillsboro residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in Hillsboro'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.
Run cold water for 30 seconds before drinking, especially in the morning. Lead and copper leach from household plumbing when water sits in pipes.
Hillsboro'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 Hillsboro
Industrial polluters nearby
Reported releases to surface water by facilities near Hillsboro, ranked by pounds discharged annually.
| Facility | Top chemical | To surface water (lbs/yr) | Distance |
|---|---|---|---|
SPRINKMAN MANUFACTURING ELROY, WI53929 | — | — | 7.0 mi |
WABASH (WALKER STAINLESS EQUIPMENT CO) ELROY, WI53929 | — | — | 6.8 mi |
LAND O'LAKES INC. - HILLSBORO HILLSBORO, WI54634 | — | — | 0.2 mi |
Source: EPA Toxic Release Inventory (TRI) 2023
Flood & disaster history
Vernon County has experienced 8 federally declared disasters since 1969. Flooding and severe weather can compromise water treatment infrastructure and introduce contaminants into drinking water supplies.
Recommended water filters
Based on contaminants detected in Hillsboro's water supply, we recommend the following filter types.
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. | 3.2 | 15 | ppb | Inorganic | Safe |
| Copper (90th percentile) CopperInorganic A metal that enters drinking water mainly through corrosion of copper plumbing. Small amounts are essential for health, but excess levels are harmful. Health EffectsGastrointestinal distress (nausea, vomiting, diarrhea) at short-term high levels; liver and kidney damage from long-term exposure. EPA Limit1.3 mg/L action level Common SourcesCorrosion of copper household plumbing, erosion of natural deposits. | 1.45 | 1.3 | mg/L | Inorganic | Over Limit |
Lead level trend (90th percentile)
Copper level trend (90th percentile)
See how Hillsboro compares by contaminant
Explore where Hillsboro ranks among all Wisconsin cities for specific contaminants.
Water source & infrastructure
Where Hillsboro's water comes from
Hillsboro'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 1,385 people through 2 water systems.
Water systems serving Hillsboro
| System Name | PWSID | Population | Source |
|---|---|---|---|
| HILLSBORO WATERWORKS | WI6630257 | 1,325 | GW |
| MARELL COURTS AND RENTALS LLC | WI6630256 | 60 | GW |
How Hillsboro compares
Full Wisconsin rankings →Hillsboro's score of 66/100 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 Hillsboro, WI
Learn more about your water
Guides and resources related to Hillsboro's water quality findings.
Explore water quality across Vernon
Frequently asked questions
Is Hillsboro, WI tap water safe to drink?
Hillsboro's water quality earned a grade of C+ (66/100). Some concerns have been identified. Consider a water filter for an extra layer of protection. The city ranks #369 out of 446 cities tested in Wisconsin.
What contaminants are in Hillsboro's water?
Lead was measured at 3.2 ppb (90th percentile). 53 violations are on record.
How is Hillsboro'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 Hillsboro?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Hillsboro's water come from?
Hillsboro's water is sourced from Groundwater. The city has 2 water systems serving approximately 1,385 residents.
What health violations has Hillsboro's water system had?
Hillsboro has 13 health-based violations on record. The most recent violation was recorded in July 2023. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 21 violations remain unresolved.
Is Hillsboro's groundwater at risk of contamination?
Hillsboro 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 53 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 Hillsboro's water compare to other cities?
Hillsboro ranks #369 out of 446 cities in Wisconsin (better than 17% of state cities) and #11441 out of 15744 cities nationally (27th percentile). The grade of C+ reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.