City of Williams
EPA ID: AZ0403026 · 3,145 people served · 1 ZIP code
With 6 unresolved EPA violations, City of Williams is currently out of full compliance — approximately 3,145 people in its service area.
Data: EPA SDWIS Last verified: 2026-04-02
Compliance Trajectory
Worsening · Risk tier: High · 95% chance of violation in next 12 months
Violations went from 3 (2022) to 2 (2025). The pattern suggests growing compliance challenges.
Service Area Map
Coverage area for City of Williams Source: EPA SDWIS service area boundaries.
Service area boundary — Grade B
Service Area Demographics
The City of Williams serves a community with a median household income of $74,583 and an estimated 6,669 residents across its service area.
Environmental Justice Note: 39% of the population in this service area is classified as disadvantaged under EPA's EJScreen criteria. Communities with higher disadvantaged populations often face disproportionate environmental and health burdens, including aging water infrastructure and limited resources for remediation.
💧 Where Does Your Water Come From?
City of Williams's water is pumped from underground aquifers. Groundwater is naturally filtered through rock and soil, but it can be vulnerable to PFAS contamination, nitrates from agriculture, and industrial chemicals that seep into the water table.
About 6% of homes in Coconino County, Arizona rely on private wells rather than public water systems. Private well owners are responsible for their own water testing and treatment.
Wastewater Proximity Note: This service area ranks in the 60th percentile nationally for proximity to wastewater discharge points.
Infrastructure Risk
Detected Contaminants
How City of Williams compares to EPA limits
What This Means For You
Total Trihalomethanes (TTHM) at 2 mg/L exceeds the EPA maximum of 0.08 mg/L. Bladder & rectal cancer risk; reproductive concerns. Consider granular activated carbon (GAC) filtration.
Chlorite at 5 mg/L exceeds the EPA maximum of 1 mg/L. Anemia and nervous system effects in infants and children. Consider ferrous sulfate reduction filtration.
Fecal Coliform at 5 presence exceeds the EPA maximum of presence.
E. coli at 4 Zero tolerance (any positive sample triggers immediate action) exceeds the EPA maximum of Zero tolerance (any positive sample triggers immediate action). Severe GI illness; potentially fatal kidney failure in children. Consider UV disinfection (99.99%) filtration.
Surface Water Treatment Rule at 3 mg/L exceeds the EPA maximum of mg/L.
Total Trihalomethanes (TTHM) was detected in this water system. granular activated carbon (GAC) filtration can reduce exposure.
Find a certified water filter →Comparable Water Systems
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Estimated Remediation Costs
Average estimated costs across ZIP codes served by this system
Based on national averages for common remediation projects. Actual costs vary by property. Only issues flagged by EPA, FEMA, or state data for each ZIP code are included.
System Overview
City of Williams (EPA ID: AZ0403026) is a community water system in Arizona that serves approximately 3,145 people from groundwater sources.
This system serves ZIP code 86046 in Williams.
Average Home Safety Score: B (74/100)
Based on water quality violations, lead levels, and radon risk across all ZIP codes served by this system.
Violation History
Recent Violations
| Date | Contaminant | Type | Status |
|---|---|---|---|
| July 1, 2025 | Surface Water Treatment Rule | Monitoring | Resolved |
| May 28, 2025 | Total Coliform | Monitoring | Resolved |
| May 1, 2025 | Revised Total Coliform Rule | Monitoring | Resolved |
| April 13, 2025 | Consumer Confidence Report Rule | Health-based | Resolved |
| January 1, 2025 | Total Trihalomethanes (TTHM) | Monitoring | Unresolved |
| December 1, 2024 | Consumer Confidence Report Rule | Monitoring | Resolved |
| January 1, 2024 | Total Trihalomethanes (TTHM) | Monitoring | Resolved |
| October 2, 2023 | Surface Water Treatment Rule | Monitoring | Resolved |
| July 1, 2023 | Chlorite | Monitoring | Unresolved |
| May 1, 2023 | Fecal Coliform | Health-based | Resolved |
| April 1, 2023 | Fecal Coliform | Health-based | Resolved |
| January 31, 2023 | Lead and Copper Rule | Monitoring | Resolved |
| January 1, 2023 | Chlorite | Monitoring | Unresolved |
Contaminants Detected
The following contaminants have been flagged in EPA records for this water system:
| Contaminant | Category | Violations | Health-Based |
|---|---|---|---|
| Chlorite | Disinfection Byproducts | 5 | Yes |
| Fecal Coliform | Microbiological | 5 | Yes |
| E. coli | Microbiological | 4 | No |
| Surface Water Treatment Rule | Treatment Failure | 3 | No |
| Consumer Confidence Report Rule | Reporting Failure | 3 | Yes |
| Total Trihalomethanes (TTHM) | Disinfection Byproducts | 2 | No |
| Stage 1 DBP Rule | Treatment Failure | 2 | No |
| Revised Total Coliform Rule | Microbiological | 2 | No |
| Barium | Inorganic | 1 | Yes |
| Total Coliform | Microbiological | 1 | No |
| Lead and Copper Rule | Treatment Failure | 1 | No |
Health Risk Details
Chlorite (EPA limit: 1 mg/L)
Anemia and nervous system effects in infants and children At-risk groups: infants, developing fetuses, people with G6PD deficiency.
Removal methods: ferrous sulfate reduction, activated carbon, reverse osmosis. Find the right filter →
Lead & Copper
EPA Lead and Copper Rule sampling data for ZIP codes served by this system:
| ZIP Code | Lead Level | Exceeds Limit | Sample Date |
|---|---|---|---|
| 86046 | 0.0017 mg/L | No | N/A |
Radon Risk in Service Area
Dominant radon zone for ZIP codes served by this system: Zone 2 (Moderate Risk)
The EPA recommends testing homes in Zone 1 and Zone 2 areas for radon.
Need help with your water quality?
Typical cost: Water test: typically $20–$50 (DIY kit) · Professional inspection: $150–$400
Find the Right Water FilterFree tip: Let cold water run for 2 minutes before drinking — this helps flush lead from your pipes.
ZIP Codes Served
Coverage: Service area ZIP codes sourced from EPA Community Water System Service Area Boundaries v3 (March 2026 release). These ZIPs reflect the actual deployment footprint recorded by AZ or modeled from parcel and building-footprint data.
- 86046 — Williams
Data Sources
This report uses public data from the EPA Safe Drinking Water Information System (SDWIS). View the full compliance record for City of Williams (AZ0403026) on EPA.gov.
Frequently Asked Questions
Is City of Williams water safe to drink?
City of Williams has recorded 6 health-based violations in the past 5 years. While the system is required to treat water to meet federal standards, you may want to consider additional precautions such as a certified water filter.
How many people does City of Williams serve?
City of Williams serves approximately 3,145 people across 1 ZIP code in Arizona.
Where does City of Williams get its water?
The primary water source is groundwater.
Lead Service Line Inventory
Service line breakdown reported under the federal Lead and Copper Rule Improvements (LCRI) inventory requirement:
This system reports zero confirmed lead service lines in its inventory. Unknown-material counts may still warrant verification.
Federal LCRI rule (effective October 2024) requires every public water system to inventory its service lines and complete lead-line replacement within 10 years.
Source: EPA SDWIS Federal Service Line Inventory (Phase 2) · Submitted 2026
ZipCheckup is not affiliated with the utility or state agency. Inventory figures render verbatim from the public LCRI submission cited above; ZipCheckup does not perform inspections or replacements.
Frequently Asked Questions
What You Can Do
Test your water
Home test kits can detect lead, bacteria, and other contaminants at your tap. Find the right filter →
Check your specific ZIP code
Water quality can vary within a system. View nearest ZIP report →
Contact your utility
City of Williams (EPA ID: AZ0403026) — request the latest Consumer Confidence Report or ask about specific contaminants.