Is Madison, CA Tap Water Safe to Drink?
Graded D+, with 5 unresolved violations on record. See what was cited — and what it means for your tap. What to do next ↓
52/100
waterverge.com Madison, CA — Water Quality Report
Madison's drinking water received a grade of D+ (52 out of 100), indicating poor water quality. The city's 1 water system serves approximately 876 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 153 violations on record, including 6 health-based violations. 5 remain unresolved.
What to know about Madison's water
Madison ranks #599 out of 694 cities in California for water quality, placing it among the lowest-rated in the state.
Madison 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, Madison may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
The system has seen 129 violations in the past five years, suggesting a pattern of compliance challenges that residents should monitor closely.
Water quality score
See methodology →Is Madison, CA water safe to drink?
Madison's drinking water has significant quality concerns based on EPA testing data. With a grade of D+ (52/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 1 water system serves approximately 876 residents using groundwater (wells).
Recent water quality updates for Madison
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Madison's water quality assessment. Grade: D+ (52/100).
Contaminants: p-Dichlorobenzene, Arsenic, Vinyl chloride.
1 health-based. Contaminants: LEAD AND COPPER RULE REVISIONS.
Contaminants: Revised Total Coliform Rule.
Federal disaster declaration (FEMA DR-4683). Flood event — may have impacted local water infrastructure.
Federal disaster declaration (FEMA DR-3591). Flood event — may have impacted local water infrastructure.
Key contaminant findings
Based on the most recent EPA sampling data for Madison's water supply.
Well within EPA limits.
Violation history
Madison's water system has 153 total violations on record, including 6 health-based violations. 5 remain unresolved. 129 violations were issued in the last 5 years.
Flood & environmental risk
Yolo County has experienced 8 federally declared disasters since 1964. 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 Madison's water come from?
Madison's drinking water comes from groundwater (wells), supplied by 1 water system serving approximately 876 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate.
What Madison residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in Madison'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.
Madison'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 Madison
Industrial polluters nearby
Reported releases to surface water by facilities near Madison, ranked by pounds discharged annually.
| Facility | Top chemical | To surface water (lbs/yr) | Distance |
|---|---|---|---|
WOODLAND PLANT WOODLAND, CA95695 | — | — | 5.7 mi |
PAVESTONE - WINTERS CA PLANT WINTERS, CA95694 | — | — | 9.4 mi |
Source: EPA Toxic Release Inventory (TRI) 2023
Flood & disaster history
Yolo County has experienced 8 federally declared disasters since 1964. 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 Madison compares by contaminant
Explore where Madison ranks among all California cities for specific contaminants.
Water source & infrastructure
Where Madison's water comes from
Madison'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 876 people through 1 water system.
Water systems serving Madison
| System Name | PWSID | Population | Source |
|---|---|---|---|
| MADISON SERVICE DIST | CA5700571 | 876 | GW |
How Madison compares
Full California rankings →Madison's score of 52/100 is on par with the average of 57/100 among major California cities. It outscores 5 of 10 nearby cities.
Nearby cities
View California rankings →Learn more about your water
Guides and resources related to Madison's water quality findings.
Explore water quality across Yolo
Frequently asked questions
Is Madison, CA tap water safe to drink?
Madison's water quality earned a grade of D+ (52/100). Significant issues have been found. A water filter is strongly recommended. The city ranks #599 out of 694 cities tested in California.
What contaminants are in Madison's water?
Lead was measured at 0.0 ppb (90th percentile). 153 violations are on record.
How is Madison'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 Madison?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Madison's water come from?
Madison's water is sourced from Groundwater. The city has 1 water system serving approximately 876 residents.
What health violations has Madison's water system had?
Madison has 6 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. 5 violations remain unresolved.
Is Madison's groundwater at risk of contamination?
Madison 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 153 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 Madison's water compare to other cities?
Madison ranks #599 out of 694 cities in California (better than 14% of state cities) and #12830 out of 15744 cities nationally (19th percentile). The grade of D+ reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.
Does Madison's small water system affect quality?
Madison's system serves approximately 876 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 153 violations on record.