States › California › Alameda County

Alameda County, CA Water Quality

Water quality data for 4 public water systems serving Alameda County, California — based on EPA SDWIS enforcement records, lead testing results, and health-based violation history.

📅 2026 Report 🔄 Data updated 2026 Q2 📍 4 water systems · 20 cities
✅
Excellent — All Systems Performing Well

Water quality across the county is outstanding with minimal violations and very low lead levels.

A

Alameda County Earns a A

Alameda County: 20 communities across 4 water systems. 100.0% have no open violations.

  • Median lead where detected: 6.70 ppb
  • 4 communities with a lead detection, 16 reporting none detected
  • 0 communities with PFAS above the federal limit
  • 0 with significant inspection deficiencies
  • 100.0% of communities have no open violations
6.7 ppb
Median Lead Level
County-wide, 90th percentile
4
Water Systems
Active CWS & NTNCWS
100%
Violation-Free
No active violations on record
How we grade counties: MyWaterIQ uses EPA SDWIS enforcement data — actual MCL violations and lead test results — not the aspirational MCLG targets used by some sites. A grade reflects real compliance history, not theoretical risk. Learn more →

Cities by Water Quality

⭐ Best Performing
  • Oakland
    Not detected
    No federal limits exceeded on record
    A
  • Hayward
    Not detected
    No federal limits exceeded on record
    B
  • Berkeley
    Not detected
    No federal limits exceeded on record
    A
  • San Leandro
    Not detected
    No federal limits exceeded on record
    A
  • Alameda
    Not detected
    No federal limits exceeded on record
    A
⚠ Needs Attention
  • Fremont
    Not detected
    Copper above the 1,300 ppb action level
    A
  • Union City
    Not detected
    Copper above the 1,300 ppb action level
    A
  • Newark
    Not detected
    Copper above the 1,300 ppb action level
    A
  • Pleasanton
    6.70 ppb
    Lead at 6.70 ppb, above a third of the action level
    B
  • Dublin
    6.70 ppb
    Lead at 6.70 ppb, above a third of the action level
    B
County Lead Level — Median 6.7 ppb
Based on most recent 90th percentile lead tests across all reporting systems
0 ppb5 ppb10 ppb15 ppb
County median: 6.7 ppb — 44.7% of the federal action level
Systems by Lead Level
5 – 10 ppb
4
No Data
16

All Cities in Alameda County

Oakland Not detected A
Fremont Not detected A
Hayward Not detected B
Berkeley Not detected A
San Leandro Not detected A
Alameda Not detected A
Union City Not detected A
Castro Valley Not detected A
Newark Not detected A
Pleasanton 6.70 ppb B
Dublin 6.70 ppb B
Livermore 6.70 ppb B
San Lorenzo Not detected A
Ashland Not detected A
Albany Not detected A
Emeryville Not detected A
Piedmont Not detected A
Cherryland Not detected A
Fairview Not detected B
Sunol 6.70 ppb B
Showing 20 cities
No active violations Active violations

About Alameda County Drinking Water

Alameda County is served by 4 water systems covering 20 communities. No community here has an open violation on record.

Of the communities reporting lead results, 4 recorded a detection, with a median of 6.70 ppb — 45% of the federal action level. 16 reported none detected, which means below the laboratory limit rather than an absence of lead.

No community here has PFAS above the federal limit on record. State inspectors recorded no significant deficiencies.

Frequently Asked Questions

Is Alameda County tap water safe to drink?▼
No community in Alameda County has an open violation on record. No community has PFAS above the federal limit on record.
What is the lead level in Alameda County?▼
Among communities with a detection the median is 6.70 ppb, 45% of the 15 ppb action level. 16 reported none detected and 0 reported no result.
How many water systems serve Alameda County?▼
4 community water systems serve 20 communities here.
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