Is Stockton, IL Tap Water Safe to Drink?
Graded A+, with 1 unresolved violation on record. See what was cited — and what it means for your tap. What to do next ↓
95.3/100
waterverge.com Stockton, IL — Water Quality Report
Stockton's drinking water received a grade of A+ (95.3 out of 100), indicating excellent water quality. The city's 1 water system serves approximately 1,728 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 22 violations on record, including 0 health-based violations. 1 remains unresolved.
What to know about Stockton's water
Stockton ranks #12 out of 891 cities in Illinois for water quality, placing it one of the best in the state.
Stockton 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, Stockton may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
Water quality score
See methodology →Is Stockton, IL water safe to drink?
Stockton's tap water meets most EPA standards but has areas that warrant attention. With a grade of A+ (95.3/100), some contaminant levels or compliance issues suggest that residents may benefit from additional filtration. The city's 1 water system serves approximately 1,728 residents using groundwater (wells).
Recent water quality updates for Stockton
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Stockton's water quality assessment. Grade: A+ (95.3/100).
Contaminants: Combined Radium (-226 and -228).
Federal disaster declaration (FEMA DR-3230). Hurricane event — may have impacted local water infrastructure.
Federal disaster declaration (FEMA DR-1368). Flood event — may have impacted local water infrastructure.
Contaminants: Coliform (TCR).
Contaminants: o-Dichlorobenzene, p-Dichlorobenzene, 1,1-Dichloroethylene.
Key contaminant findings
Based on the most recent EPA sampling data for Stockton's water supply.
Well within EPA limits.
Violation history
Stockton's water system has 22 total violations on record, including 0 health-based violations. 1 remain unresolved. 1 violation was issued in the last 5 years.
Flood & environmental risk
Jo Daviess County has experienced 7 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 Stockton's water come from?
Stockton's drinking water comes from groundwater (wells), supplied by 1 water system serving approximately 1,728 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate.
What Stockton 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.
Stockton'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 Stockton
Industrial polluters nearby
Reported releases to surface water by facilities near Stockton, ranked by pounds discharged annually.
| Facility | Top chemical | To surface water (lbs/yr) | Distance |
|---|---|---|---|
KOLB LENA CHEESE INC. LENA, IL61048 | — | — | 4.5 mi |
BREWSTER - STOCKTON PLANT STOCKTON, IL61085 | — | — | 0.5 mi |
Source: EPA Toxic Release Inventory (TRI) 2023
Flood & disaster history
Jo Daviess County has experienced 7 federally declared disasters since 1969. 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. | 0.0 | 15 | ppb | Inorganic | Safe |
Lead level trend (90th percentile)
See how Stockton compares by contaminant
Explore where Stockton ranks among all Illinois cities for specific contaminants.
Water source & infrastructure
Where Stockton's water comes from
Stockton'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 1,728 people through 1 water system.
Water systems serving Stockton
| System Name | PWSID | Population | Source |
|---|---|---|---|
| STOCKTON | IL0850450 | 1,728 | GW |
How Stockton compares
Full Illinois rankings →Stockton's score of 95.3/100 is above the average of 56/100 among major Illinois cities. It outscores 10 of 10 nearby cities.
Nearby cities
View Illinois rankings →About Stockton, IL
Learn more about your water
Guides and resources related to Stockton's water quality findings.
Explore water quality across Jo Daviess
Frequently asked questions
Is Stockton, IL tap water safe to drink?
Stockton's water quality earned a grade of A+ (95.3/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #12 out of 891 cities tested in Illinois.
What contaminants are in Stockton's water?
Lead was measured at 0.0 ppb (90th percentile). 22 violations are on record.
How is Stockton'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 Stockton?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Stockton's water come from?
Stockton's water is sourced from Groundwater. The city has 1 water system serving approximately 1,728 residents.
Is Stockton's groundwater at risk of contamination?
Stockton 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 22 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 Stockton's water compare to other cities?
Stockton ranks #12 out of 891 cities in Illinois (better than 99% of state cities) and #331 out of 15744 cities nationally (98th percentile). The grade of A+ reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.
Does Stockton's small water system affect quality?
Stockton's system serves approximately 1,728 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 22 violations on record.