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WaterSafeCheck

Costa Mesa, CA Tap Water Quality

Water safety reports for all 3 ZIP codes in Costa Mesa, California

Average Score

55/100

Health Violations

48

ZIP Codes

3

High Lead Risk

2

of 3 ZIP codes

C

About Tap Water in Costa Mesa, CA

Water quality in Costa Mesa, CA is currently rated with a moderate C grade (average score: 55/100 across 3 ZIP codes). This rating indicates that while the water provided by Mesa Water District is treated and regulated, there have been notable compliance issues or contaminant detections recently. Residents should stay informed about the specific challenges affecting their local supply.

The accumulation of 48 health-based violations over the past 5 years highlights systemic challenges within Costa Mesa's water infrastructure. When violations occur, it means that drinking water tests revealed contaminant levels exceeding safe limits, triggering mandatory corrective actions by California State Water Resources Control Board. The city relies on surface water, which may require significant treatment upgrades to address these recurring issues.

Additionally, lead exposure risk remains a critical issue for certain neighborhoods. EPA data indicates that 2 out of 3 ZIP codes in Costa Mesa are rated as High or Very High risk for lead. This risk is often driven by aging homes with pre-1986 plumbing containing lead solder or service lines. Families in these areas should test their tap water and consider NSF/ANSI 53 certified filters.

⚠ Lead Risk Alert: Some ZIP codes in Costa Mesa are rated High or Very High for lead exposure risk based on EPA data. Search your specific ZIP code for a detailed lead level report.

Health-Based Contaminant Violations in Costa Mesa

EPA records indicate that the following contaminants have exceeded Safe Drinking Water Act Maximum Contaminant Levels (MCLs) in Costa Mesa water systems over the past 5 years.

Contaminant 1032

Note: The presence of a past violation does not necessarily mean current water is unsafe. Utilities are required to take corrective action. Review your Consumer Confidence Report for the latest status.

Water Quality by ZIP Code — Costa Mesa, CA

Click any ZIP code for the full water quality report

C
92627

Costa Mesa, CA

Score: 57/10016 violations
C
92628

Costa Mesa, CA

Score: 55/10016 violations
D
92626

Costa Mesa, CA

Score: 52/10016 violations

Frequently Asked Questions — Costa Mesa Water Quality

Is tap water safe to drink in Costa Mesa, CA?+
Tap water in Costa Mesa has a grade of C, indicating compliance concerns in recent years. Families with young children or pregnant women should consider using a certified NSF/ANSI 53 water filter for drinking and cooking.
What is the water quality score for Costa Mesa?+
The average water quality score across 3 ZIP codes in Costa Mesa, CA is 55/100. Scores are derived from EPA violation history, lead levels, enforcement actions, and infrastructure risk indicators. Individual ZIP codes may vary — search your specific ZIP above for a personalized report.
Does Costa Mesa have lead in its tap water?+
2 out of 3 ZIP codes in Costa Mesa are rated High or Very High for lead exposure risk. Older homes built before 1986 may have lead service lines or plumbing fixtures. Residents should run their tap for 30 seconds before use and consider a certified NSF/ANSI 53 lead filter.
How do I get the water quality report for Costa Mesa?+
Each ZIP code in Costa Mesa has a full water quality report on this site — click any ZIP code below. You can also get the annual Consumer Confidence Report (CCR) from your local water utility. The CCR is required to be published every year by July 1 and contains actual contaminant measurements and violation history.
Where does Costa Mesa's tap water come from?+
Tap water in Costa Mesa, CA primarily comes from surface water. Surface water systems treat water from rivers, lakes, or reservoirs using filtration, sedimentation, and disinfection before it reaches your tap.

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