Epcor - San Tan
EPA ID: AZ0411128 · 87,435 people served · 4 ZIP codes
Epcor - San Tan shows 8 open EPA violations in current federal records for approximately 87,435 people.
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 2 (2021) to 3 (2025). The pattern suggests growing compliance challenges.
Service Area Map
Coverage area for Epcor - San Tan Source: EPA SDWIS service area boundaries.
Service area boundary — Grade C
Service Area Demographics
The Epcor - San Tan serves a community with a median household income of $94,085 and an estimated 218,605 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?
Epcor - San Tan'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 1% of homes in Pinal County, Arizona rely on private wells rather than public water systems. Private well owners are responsible for their own water testing and treatment.
Infrastructure Risk
Detected Contaminants
How Epcor - San Tan compares to EPA limits
What This Means For You
Lead at 4 mg/L (action level) exceeds the EPA maximum of 0.015 mg/L (action level). Brain damage in children, kidney & blood pressure in adults. Consider reverse osmosis filtration.
Total Trihalomethanes (TTHM) at 1 mg/L exceeds the EPA maximum of 0.08 mg/L. Bladder & rectal cancer risk; reproductive concerns. Consider granular activated carbon (GAC) filtration.
Revised Total Coliform Rule at 11 presence exceeds the EPA maximum of presence.
Surface Water Treatment Rule at 5 mg/L exceeds the EPA maximum of mg/L.
Consumer Confidence Report Rule at 5 mg/L exceeds the EPA maximum of mg/L.
PFAS Detected in Service Area
PFAS ("forever chemicals") have been detected in water serving this system's area. 13 detections recorded. 3 exceed federal EPA limits (4 ppt for PFOA/PFOS). 1 exceeds state limits.
Lead was detected in this water system. reverse osmosis 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
Epcor - San Tan (EPA ID: AZ0411128) is a community water system in Arizona that serves approximately 87,435 people from groundwater sources.
This system provides water to 4 ZIP codes across 3 communities.
Average Home Safety Score: C (69/100)
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 | Unresolved |
| July 1, 2025 | Lead | Monitoring | Unresolved |
| March 1, 2025 | Revised Total Coliform Rule | Monitoring | Unresolved |
| February 1, 2025 | Revised Total Coliform Rule | Monitoring | Unresolved |
| January 1, 2025 | Revised Total Coliform Rule | Monitoring | Unresolved |
| December 1, 2024 | Revised Total Coliform Rule | Monitoring | Resolved |
| October 1, 2024 | Revised Total Coliform Rule | Monitoring | Resolved |
| September 1, 2024 | Revised Total Coliform Rule | Monitoring | Resolved |
| April 1, 2024 | Revised Total Coliform Rule | Monitoring | Resolved |
| January 1, 2024 | Lead | Monitoring | Resolved |
| November 10, 2023 | Lead and Copper Rule | Monitoring | Resolved |
| November 1, 2023 | Consumer Confidence Report Rule | Monitoring | Resolved |
| October 2, 2023 | Surface Water Treatment Rule | Monitoring | Resolved |
| July 1, 2023 | Surface Water Treatment Rule | Monitoring | Resolved |
| January 1, 2023 | Lead | Monitoring | Unresolved |
| January 1, 2023 | Stage 1 DBP Rule | Monitoring | Unresolved |
Contaminants Detected
The following contaminants have been flagged in EPA records for this water system:
| Contaminant | Category | Violations | Health-Based |
|---|---|---|---|
| Revised Total Coliform Rule | Microbiological | 11 | No |
| Surface Water Treatment Rule | Treatment Failure | 5 | No |
| Consumer Confidence Report Rule | Reporting Failure | 5 | No |
| Lead | Inorganic | 4 | No |
| Lead and Copper Rule | Treatment Failure | 3 | No |
| Stage 1 DBP Rule | Treatment Failure | 2 | No |
| Total Trihalomethanes (TTHM) | Disinfection Byproducts | 1 | No |
Lead & Copper
EPA Lead and Copper Rule sampling data for ZIP codes served by this system:
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.
Data Sources
This report uses public data from the EPA Safe Drinking Water Information System (SDWIS). View the full compliance record for Epcor - San Tan (AZ0411128) on EPA.gov.
Frequently Asked Questions
Is Epcor - San Tan water safe to drink?
Epcor - San Tan has only monitoring/reporting violations, which are procedural in nature. The system meets federal health-based standards.
How many people does Epcor - San Tan serve?
Epcor - San Tan serves approximately 87,435 people across 4 ZIP codes in Arizona.
Where does Epcor - San Tan get its water?
The primary water source is groundwater.
Contact Your Water Utility
Public-record contact information for the water utility serving this system. Use these channels to request water quality reports, ask about service, or report issues directly.
Contact information from SAN TAN Consumer Confidence Report.
ZipCheckup is not affiliated with this water utility, does not act as its agent, and does not provide customer support for it. Contact details shown are public-record information from CCR filings. For service issues, contact the utility directly using the information above.
Water Source & Treatment
Where this water originates and how it's treated before reaching your tap.
Source: SAN TAN Consumer Confidence Report.
ZipCheckup is not affiliated with this water utility. Treatment and source data are sourced from the utility's published CCR filings.
A Source Water Assessment is on file with the Arizona Department of Environmental Quality (ADEQ) and a copy of it can be obtained by contacting ADEQ’s Record Center. The Source Water Assessment Report concluded with a low risk designation for our water system.
Treatment regime
How this utility classifies its treatment process and what each reported treatment chemical does.
Treatment chemicals and what each one does
Chemical names are reported verbatim by the utility. Purpose categories are ZipCheckup annotations based on standard drinking-water treatment practice.
Treatment classification and chemical list sourced from SAN TAN Consumer Confidence Report.
Treatment intensity is a ZipCheckup-derived classification based on the chemicals and processes the utility reports. Chemicals and contamination sources are taken verbatim from the utility's CCR filing. Routine federal monitoring and contaminant testing shown elsewhere on this page determine whether the water meets safety standards, not the treatment classification.
Federal UCMR5 PFAS Monitoring: Tested Clean
This water system was tested under the federal EPA Unregulated Contaminant Monitoring Rule (UCMR5). No PFAS compounds were detected.
Current MCL reflects the lowest state-enforceable limit (NYS 10 ppt for PFOA/PFOS, effective August 2020). The federal final MCL of 4 ppt for PFOA/PFOS (EPA April 2024 rule) is not enforceable until April 2029. Detections above 4 ppt but below 10 ppt are below current MCL but above the future federal limit.
Source: U.S. EPA UCMR5 (Unregulated Contaminant Monitoring Rule, 5th cycle) — per-system federal sampling, 2023–2025. EPA UCMR5 monitoring program →
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.
Hard water detected in SAN TAN
Your utility's most recent Consumer Confidence Report flagged water hardness above EPA's secondary maximum contaminant level (120 ppm CaCO₃). This may cause scale buildup, reduced appliance lifespan, and dry skin or hair.
There are three common approaches to treating hard water: salt-based ion-exchange softeners (most effective, require salt refills), salt-free conditioners (lower maintenance, scale prevention only), and reverse osmosis at the kitchen sink (cooking and drinking water only). Aquasana, EcoWater, Pelican, and SpringWell are among the major US brands.
Paid Partner. ZipCheckup earns commission on Aquasana purchases. We do not test water or verify product effectiveness for specific hardness levels — manufacturer claims are theirs alone. Consult a certified water-quality professional for personalized advice.
Hardness data parsed from this utility's most recent Consumer Confidence Report. Severity bands per USGS hard water classification.
Notable events and violations
This section summarizes events the utility chose to disclose in its most recent Consumer Confidence Report, plus any federal compliance violations the utility recorded against itself. Both lists are utility-authored — ZipCheckup does not audit, judge, or reorder them.
Notable events from the utility's CCR
These bullet entries are the utility's own narration of operational, regulatory, or infrastructure events during the reporting period.
- EPCOR failed to test our drinking water at Entry Point to the Distribution System #008, Sierra Vista Water Plant, for Volatile Organic Chemicals (VOCs) in 2024.
ZipCheckup note: items above reflect what the utility published in its most recent CCR. Federal violation records are also tracked separately by the EPA Safe Drinking Water Information System (SDWIS) — the SDWIS record is the authoritative federal source for any specific regulatory action.
How Water Systems Appear in Rankings
Water systems are evaluated by violation history, contaminant detections, and service population. Larger systems with more service connections appear in more rankings.
- #25 / 50 Highest Exposure Burden (Arizona)
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
Epcor - San Tan (EPA ID: AZ0411128) — request the latest Consumer Confidence Report or ask about specific contaminants.