Mesa Water District
EPA ID: CA3010004 · 110,000 people served · 8 ZIP codes
Not yet resolved: 28 EPA violations at Mesa Water District, affecting about 110,000 residents.
Data: EPA SDWIS Last verified: 2026-04-02
Compliance Trajectory
Stable · Risk tier: High · 95% chance of violation in next 12 months
Violations went from 3 (2022) to 22 (2024). Violation counts have remained relatively steady.
Service Area Map
Coverage area for Mesa Water District Source: EPA SDWIS service area boundaries.
Service area boundary — Grade C
Service Area Demographics
The Mesa Water District serves a community with a median household income of $105,039 and an estimated 341,019 residents across its service area. Approximately 72% of housing stock was built before 1986, which increases the likelihood of lead service lines and older plumbing.
🌊 Where Does Your Water Come From?
Mesa Water District's water is drawn from rivers, lakes, or reservoirs. Surface water sources are more exposed to agricultural runoff, stormwater, and upstream discharges, but they typically receive more intensive treatment before reaching your tap.
About 2% of homes in Orange County, California rely on private wells rather than public water systems. Private well owners are responsible for their own water testing and treatment.
Superfund Proximity Note: This service area ranks in the 60th percentile nationally for proximity to Superfund (NPL) sites.
Infrastructure Risk
Detected Contaminants
How Mesa Water District compares to EPA limits
What This Means For You
Contaminant 1032 at 17 mg/L exceeds the EPA maximum of mg/L.
Contaminant 1028 at 11 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. 20 detections recorded. 4 exceed federal EPA limits (4 ppt for PFOA/PFOS). 4 exceed state limits.
Comparable Water Systems
Similar-sized systems in California
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
Mesa Water District (EPA ID: CA3010004) is a community water system in California that serves approximately 110,000 people from surface water sources.
This system provides water to 8 ZIP codes across 4 communities.
Average Home Safety Score: C (55/100)
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 |
|---|---|---|---|
| October 1, 2024 | Contaminant 1032 | Health-based | Unresolved |
| July 1, 2024 | Contaminant 1032 | Health-based | Unresolved |
| July 1, 2024 | Contaminant 1032 | Monitoring | Unresolved |
| April 1, 2024 | Contaminant 1032 | Health-based | Unresolved |
| January 1, 2024 | Contaminant 1032 | Health-based | Unresolved |
| January 1, 2024 | Contaminant 1028 | Monitoring | Unresolved |
| October 1, 2023 | Contaminant 1032 | Health-based | Unresolved |
| October 1, 2023 | Contaminant 1028 | Monitoring | Unresolved |
| July 1, 2023 | Contaminant 1032 | Health-based | Unresolved |
| July 1, 2023 | Contaminant 1028 | Monitoring | Unresolved |
| April 1, 2023 | Contaminant 1032 | Health-based | Unresolved |
| April 1, 2023 | Contaminant 1028 | Monitoring | Unresolved |
| January 1, 2023 | Contaminant 1032 | Health-based | Unresolved |
| January 1, 2023 | Contaminant 1028 | Monitoring | Unresolved |
Contaminants Detected
The following contaminants have been flagged in EPA records for this water system:
| Contaminant | Category | Violations | Health-Based |
|---|---|---|---|
| Contaminant 1032 | Other Violation | 17 | Yes |
| Contaminant 1028 | Other Violation | 11 | No |
Lead & Copper
No Lead and Copper Rule sampling data available for this water system.
Radon Risk in Service Area
Dominant radon zone for ZIP codes served by this system: Zone 3 (Low Risk)
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: 7 ZIP codes confirmed via EPA Community Water System Service Area Boundaries v3 plus 1 additional ZIP inferred from SDWIS registry data. The EPA-confirmed set is the most reliable; SDWIS-inferred entries may be narrower than the real deployment area.
- 92612 — Irvine
- 92626 — Costa Mesa
- 92627 — Costa Mesa
- 92628 — Costa Mesa
- 92660 — Newport Beach
- 92663 — Newport Beach
- 92704 — Santa Ana
- 92707 — Santa Ana
Data Sources
This report uses public data from the EPA Safe Drinking Water Information System (SDWIS). View the full compliance record for Mesa Water District (CA3010004) on EPA.gov.
Frequently Asked Questions
Is Mesa Water District water safe to drink?
Mesa Water District has recorded 16 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 Mesa Water District serve?
Mesa Water District serves approximately 110,000 people across 8 ZIP codes in California.
Where does Mesa Water District get its water?
The primary water source is surface water.
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 Mesa Water District 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: Mesa Water District Consumer Confidence Report.
ZipCheckup is not affiliated with this water utility. Treatment and source data are sourced from the utility's published CCR filings.
An assessment of the drinking water sources for Mesa Water was completed in December 2002 and was updated in 2022. The sources are considered most vulnerable to the following activities: dry cleaners, gas stations, known contaminant plumes, metal plating/finishing/fabricating, plastics/synthetics producers, bus maintenance, automobile body shops/repair shops, boat services/repair/refinishing, machine shops, electronic manufacturing, furniture repair/manufacturing, sewer collection systems (residential), and underground storage tanks (non-regulated tanks).
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.
Watershed exposure sources reported
Land-use and natural conditions identified in the utility's source-water assessment as potential contamination sources upstream of treatment.
Treatment classification and chemical list sourced from Mesa Water District 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 →
Mesa Water has determined it has no lead or galvanized services that require replacement in its distribution system.
Lead Service Line Replacement Tracker
This water utility's lead service line (LSL) replacement program is tracked from public Consumer Confidence Report filings. Email signup notifies subscribers when the utility files an updated replacement plan or progress milestone.
Mesa Water District
ZipCheckup is not affiliated with this water utility. LSL replacement-program data is sourced from public CCR filings published by the utility. Subscription notifications are based on automated parsing of subsequent CCR releases.
Learn more about Lead and Copper Rule replacement requirements →
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.
Aesthetic water quality
These measurements describe the look, taste, and feel of the water this utility delivers. They are not contaminant violations — they sit alongside federal Secondary Maximum Contaminant Levels (SMCLs) which the EPA publishes as non-enforceable guidance.
Aesthetic measurements from Mesa Water District Consumer Confidence Report.
Aesthetic measurements are reported by the utility from its annual sampling. EPA Secondary MCLs are advisory thresholds — values outside them indicate aesthetic concerns such as taste or appearance, not health violations. Federal contaminant testing is shown in the sections above.
Hard water detected in Mesa Water District
Your utility reported water hardness of 237 ppm CaCO₃ (14 grains per gallon) in its most recent Consumer Confidence Report. This is in the hard range and 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.
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
Mesa Water District (EPA ID: CA3010004) — request the latest Consumer Confidence Report or ask about specific contaminants.