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Water system · PWSID CA3010004

MESA WATER DISTRICT

COSTA MESA, CA · ~110,000 people served

Check your exact address → COSTA MESA overview
100
Excellent
PurityRadar safety score

PWSID

CA3010004

State

California

City

COSTA MESA

Population served

110,000

Primary source

SWP

Score history

No change since tracking began Jun 18, 2026.

Jun 18, 2026 · score 100 Jun 18, 2026 · score 100

2 score updates logged since tracking began Jun 18, 2026. Each future EPA re-score adds a point.

PFAS & contaminant readings

Latest detections from EPA’s UCMR5 monitoring (through Dec 2023). Levels in parts per trillion (ppt).

Lithium

28,989 ppt

limit —

No federal limit

Violations & enforcement

2

Violations on record

0

Unaddressed

1

Health-based

4

Enforcement actions

From EPA ECHO (SDWIS), most recent enforcement Aug 2020. Official EPA record →

Monitoring & reporting · Combined radium-226/228 began Jan 2010 Resolved
Max contaminant level (MCL) · Total coliform health-based began Jul 2000 Resolved

Recent enforcement actions

  • State action · SFL Aug 2020
  • State action · SOX Aug 2020
  • State action · SFL Jul 2000
  • State action · SOX Jul 2000

Area water-quality monitoring

Environmental monitoring (rivers, wells, intakes) recorded in this system’s service area in the EPA/USGS Water Quality Portal since 2018 — source/ambient water, not finished tap water. Context for the watershed, not a reading from your tap.

ContaminantMedian · max · samples

Fluoride

2 stations · latest Jul 2020

0.585 · max 0.84 mg/l · 2

Lead

2 stations · latest Jul 2020

0.263 · max 0.449 ug/l · 2

Manganese

2 stations · latest Jul 2020

4.71 · max 8.34 ug/l · 2

Nitrate

1 station · latest Jul 2020

0.048 · max 0.048 mg/l as N · 2

Uranium

2 stations · latest Jul 2020

1 · max 1.78 ug/l · 2

Arsenic

1 station · latest Jul 2020

1.8 · max 1.8 ug/l · 1

Source: Water Quality Portal (EPA/USGS/state agencies). Values are as-reported and aren’t health thresholds.

This profile is built from EPA public records for system CA3010004 — SDWIS violations and UCMR5 PFAS sampling. The score is system-level and can’t account for your home’s plumbing (older pipes can add lead at the tap). For health decisions, check your exact address, read the utility’s Consumer Confidence Report, and confirm with your provider.