States › California › Merced County

Merced County, CA Water Quality

Water quality data for 15 public water systems serving Merced County, California — based on EPA SDWIS enforcement records, lead testing results, and health-based violation history.

📅 2026 Report 🔄 Data updated 2026 Q2 📍 15 water systems · 18 cities
✅
Generally Safe — Most Systems Performing Well

The majority of water systems have no active violations and lead levels well below the federal action level.

B

Merced County Earns a B

Merced County: 18 communities across 15 water systems. 72.2% have no open violations.

  • Median lead where detected: 6.00 ppb
  • 3 communities with a lead detection, 15 reporting none detected
  • 6 communities with PFAS above the federal limit
  • 0 with significant inspection deficiencies
  • 72.2% of communities have no open violations
6 ppb
Median Lead Level
County-wide, 90th percentile
15
Water Systems
Active CWS & NTNCWS
72%
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
  • Delhi
    Not detected
    No federal limits exceeded on record
    B
  • Santa Nella
    Not detected
    No federal limits exceeded on record
    B
  • El Nido
    Not detected
    No federal limits exceeded on record
    B
  • Los Banos
    Not detected
    1 health-based violation since 2015
    A
  • Dos Palos
    Not detected
    34 health-based violations since 2015
    B
⚠ Needs Attention
  • Planada
    Not detected
    PFAS above the limit at 1 of 6 sampling points
    F
  • Livingston
    Not detected
    1 violation currently open
    D
  • Winton
    Not detected
    1 violation currently open
    C
  • Gustine
    Not detected
    1 violation currently open
    C
  • Volta
    Not detected
    1 violation currently open
    C
County Lead Level — Median 6 ppb
Based on most recent 90th percentile lead tests across all reporting systems
0 ppb5 ppb10 ppb15 ppb
County median: 6 ppb — 40% of the federal action level
Systems by Lead Level
5 – 10 ppb
3
No Data
15

All Cities in Merced County

Merced Not detected B
Los Banos Not detected A
Atwater Not detected C
Livingston Not detected D
Winton Not detected C
Delhi Not detected B
Franklin 6.00 ppb C
Gustine Not detected C
Dos Palos Not detected B
Hilmar-Irwin Not detected B
Planada Not detected F
Santa Nella Not detected B
South Dos Palos Not detected B
McSwain 6.00 ppb C
Bear Creek Not detected B
Volta Not detected C
El Nido Not detected B
Ballico 7.40 ppb B
Showing 18 cities
No active violations Active violations

About Merced County Drinking Water

Merced County is served by 15 water systems covering 18 communities. 72% have no open violations.

Of the communities reporting lead results, 3 recorded a detection, with a median of 6.00 ppb — 40% of the federal action level. 15 reported none detected, which means below the laboratory limit rather than an absence of lead.

6 of 18 communities have PFAS above the limits EPA set in 2024, measured as a running annual average at each sampling point. State inspectors recorded no significant deficiencies.

Frequently Asked Questions

Is Merced County tap water safe to drink?▼
72% of communities have no open violation. 6 of 18 have PFAS above the federal limit, which is the main open concern.
What is the lead level in Merced County?▼
Among communities with a detection the median is 6.00 ppb, 40% of the 15 ppb action level. 15 reported none detected and 0 reported no result.
How many water systems serve Merced County?▼
15 community water systems serve 18 communities here.
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