Is Janesville, MI Tap Water Safe to Drink?
Graded A+ with no contaminants above EPA limits. Here's everything we tested and how Janesville ranks. What to do next ↓
96.1/100
waterverge.com Janesville, MI — Water Quality Report
Janesville's drinking water received a grade of A+ (96.1 out of 100), indicating excellent water quality. The city's 1 water system serves approximately 1,200 residents using groundwater.
Lead levels were measured at 0.7 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 8 violations on record, including 5 health-based violations. All violations have been resolved.
What to know about Janesville's water
Janesville ranks #9 out of 520 cities in Michigan for water quality, placing it one of the best in the state.
Janesville 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, Janesville may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
Water quality score
See methodology →Is Janesville, MI water safe to drink?
Based on EPA testing data, Janesville's tap water is generally safe to drink. The water system earned a grade of A+ (96.1/100), meeting federal drinking water standards across key contaminant categories. The city's 1 water system serves approximately 1,200 residents using groundwater (wells).
Recent water quality updates for Janesville
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Janesville's water quality assessment. Grade: A+ (96.1/100).
Federal disaster declaration (FEMA DR-4757). Flood event — may have impacted local water infrastructure.
Federal disaster declaration (FEMA DR-4195). Flood event — may have impacted local water infrastructure.
1 health-based. Contaminants: Coliform (TCR).
1 health-based. Contaminants: Coliform (TCR).
Contaminants: Coliform (TCR).
Key contaminant findings
Based on the most recent EPA sampling data for Janesville's water supply.
Well within EPA limits.
Violation history
Janesville's water system has 8 total violations on record, including 5 health-based violations. All violations have been resolved.
Flood & environmental risk
Oakland County has experienced 4 federally declared disasters since 1975. 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 River Rouge, Upper River Rouge, Johnson Creek, Middle River Rouge.
Where does Janesville's water come from?
Janesville's drinking water comes from groundwater (wells), supplied by 1 water system serving approximately 1,200 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate. Nearby water bodies include River Rouge (river), Upper River Rouge (river), Johnson Creek (river), Middle River Rouge (river).
What Janesville residents can do
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.
Janesville'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
Flood & disaster history
Oakland County has experienced 4 federally declared disasters since 1975. 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. | 0.7 | 15 | ppb | Inorganic | Safe |
Lead level trend (90th percentile)
See how Janesville compares by contaminant
Explore where Janesville ranks among all Michigan cities for specific contaminants.
Water source & infrastructure
Where Janesville's water comes from
Janesville'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 private ownership and serves approximately 1,200 people through 1 water system.
Water bodies near Janesville
Janesville is located near 4 notable water bodies. These water bodies contribute to the regional watershed and may indirectly affect groundwater quality.
Water systems serving Janesville
| System Name | PWSID | Population | Source |
|---|---|---|---|
| ROCKVALE MHP | WI1540126 | 1,200 | GW |
How Janesville compares
Full Michigan rankings →Janesville's score of 96.1/100 is above the average of 70/100 among major Michigan cities. It outscores 10 of 10 nearby cities.
Nearby cities
View Michigan rankings →About Janesville, MI
Wikipedia →Farmington Hills is a city in Oakland County in the U.S. state of Michigan. A northwestern suburb of Detroit, Farmington Hills is located roughly 22 miles (35.4 km) from downtown Detroit. As of the 2020 census, the city's population was 83,986, making it the second-largest community in Oakland County.
Learn more about your water
Guides and resources related to Janesville's water quality findings.
Explore water quality across Rock
Frequently asked questions
Is Janesville, MI tap water safe to drink?
Janesville's water quality earned a grade of A+ (96.1/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #9 out of 520 cities tested in Michigan.
What contaminants are in Janesville's water?
Lead was measured at 0.7 ppb (90th percentile). 8 violations are on record.
How is Janesville'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 Janesville?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Janesville's water come from?
Janesville's water is sourced from Groundwater. The city has 1 water system serving approximately 1,200 residents.
What health violations has Janesville's water system had?
Janesville has 5 health-based violations on record. The most recent violation was recorded in August 2010. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. All health violations have been resolved.
Is Janesville's groundwater at risk of contamination?
Janesville 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 8 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 Janesville's water compare to other cities?
Janesville ranks #9 out of 520 cities in Michigan (better than 98% of state cities) and #227 out of 15744 cities nationally (99th percentile). The grade of A+ reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.
Does Janesville's small water system affect quality?
Janesville's system serves approximately 1,200 residents. Small community water systems (under 3,300 people) may have fewer financial resources for infrastructure upgrades and advanced treatment technologies. However, they are held to the same EPA drinking water standards as larger systems. This system has 8 violations on record.