Is Mazon, IL Tap Water Safe to Drink?
Graded B+ — but Copper was detected above EPA limits. Here's what's in the water and how to remove it. What to do next ↓
83.6/100
waterverge.com Mazon, IL — Water Quality Report
Mazon's drinking water received a grade of B+ (83.6 out of 100), indicating good water quality. The city's 1 water system serves approximately 994 residents using groundwater.
Lead levels were measured at 0.0 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 1 health-based violation. 4 remain unresolved.
What to know about Mazon's water
Mazon ranks #435 out of 891 cities in Illinois for water quality, placing it mid-range in the state.
Mazon 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, Mazon may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
Water quality score
See methodology →Is Mazon, IL water safe to drink?
Mazon's drinking water has significant quality concerns based on EPA testing data. With a grade of B+ (83.6/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 1 water system serves approximately 994 residents using groundwater (wells).
Recent water quality updates for Mazon
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Mazon's water quality assessment. Grade: B+ (83.6/100).
Contaminants: Consumer Confidence Rule.
Contaminants: Lead and Copper Rule.
Contaminants: Lead and Copper Rule.
Federal disaster declaration (FEMA DR-4116). Flood event — may have impacted local water infrastructure.
Federal disaster declaration (FEMA DR-3230). Hurricane event — may have impacted local water infrastructure.
Key contaminant findings
Based on the most recent EPA sampling data for Mazon'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
Mazon's water system has 14 total violations on record, including 1 health-based violation. 4 remain unresolved. 1 violation was issued in the last 5 years.
Flood & environmental risk
Grundy County has experienced 5 federally declared disasters since 1972. 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 Mazon River, Illinois River, Hanson Gravel Pit.
Where does Mazon's water come from?
Mazon's drinking water comes from groundwater (wells), supplied by 1 water system serving approximately 994 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate. Nearby water bodies include Mazon River (river), Illinois River (river), Hanson Gravel Pit (river).
What Mazon residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in Mazon'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.
Mazon'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 Mazon
Industrial polluters nearby
Reported releases to surface water by facilities near Mazon, ranked by pounds discharged annually.
| Facility | Top chemical | To surface water (lbs/yr) | Distance |
|---|---|---|---|
H.B. FULLER CO MORRIS, IL60450 | — | — | 8.3 mi |
SPONGE CUSHION INC MORRIS, IL60450 | — | — | 8.6 mi |
Source: EPA Toxic Release Inventory (TRI) 2023
Flood & disaster history
Grundy County has experienced 5 federally declared disasters since 1972. Flooding and severe weather can compromise water treatment infrastructure and introduce contaminants into drinking water supplies.
Recommended water filters
Based on contaminants detected in Mazon'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. | 0.0 | 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. | 1.54 | 1.3 | mg/L | Inorganic | Over Limit |
Lead level trend (90th percentile)
Copper level trend (90th percentile)
See how Mazon compares by contaminant
Explore where Mazon ranks among all Illinois cities for specific contaminants.
Water source & infrastructure
Where Mazon's water comes from
Mazon'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 994 people through 1 water system.
Water bodies near Mazon
Mazon is located near 3 notable water bodies. These water bodies contribute to the regional watershed and may indirectly affect groundwater quality.
Water systems serving Mazon
| System Name | PWSID | Population | Source |
|---|---|---|---|
| MAZON | IL0630500 | 994 | GW |
How Mazon compares
Full Illinois rankings →Mazon's score of 83.6/100 is above the average of 56/100 among major Illinois cities. It outscores 9 of 10 nearby cities.
Nearby cities
View Illinois rankings →About Mazon, IL
Learn more about your water
Guides and resources related to Mazon's water quality findings.
Explore water quality across Grundy
Frequently asked questions
Is Mazon, IL tap water safe to drink?
Mazon's water quality earned a grade of B+ (83.6/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #435 out of 891 cities tested in Illinois.
What contaminants are in Mazon's water?
Lead was measured at 0.0 ppb (90th percentile). 14 violations are on record.
How is Mazon'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 Mazon?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Mazon's water come from?
Mazon's water is sourced from Groundwater. The city has 1 water system serving approximately 994 residents.
What health violations has Mazon's water system had?
Mazon has 1 health-based violation 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. 4 violations remain unresolved.
Is Mazon's groundwater at risk of contamination?
Mazon 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 Mazon's water compare to other cities?
Mazon ranks #435 out of 891 cities in Illinois (better than 51% of state cities) and #6345 out of 15744 cities nationally (60th percentile). The grade of B+ reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.
Does Mazon's small water system affect quality?
Mazon's system serves approximately 994 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 14 violations on record.