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St. Tammany Parish, LA Water Quality

Water quality data for 11 public water systems serving St. Tammany Parish, Louisiana — based on EPA SDWIS enforcement records, lead testing results, and health-based violation history.

📅 2026 Report 🔄 Data updated 2026 Q2 📍 11 water systems · 11 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

St. Tammany Parish Earns a B

St. Tammany Parish: 11 communities across 11 water systems. 90.9% have no open violations.

  • Median lead where detected: 2.00 ppb
  • 3 communities with a lead detection, 8 reporting none detected
  • 0 communities with PFAS above the federal limit
  • 8 with significant inspection deficiencies
  • 90.9% of communities have no open violations
2 ppb
Median Lead Level
County-wide, 90th percentile
11
Water Systems
Active CWS & NTNCWS
90%
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
  • Pearl River
    Not detected
    No federal limits exceeded on record
    A
  • Madisonville
    Not detected
    No federal limits exceeded on record
    B
  • Mandeville
    Not detected
    1 health-based violation since 2015
    A
  • Lacombe
    Not detected
    2 significant inspection deficiencies
    B
  • Eden Isle
    1.00 ppb
    1 significant inspection deficiency
    B
⚠ Needs Attention
  • Covington
    Not detected
    1 violation currently open
    D
  • Sun
    2.00 ppb
    Copper above the 1,300 ppb action level
    C
  • Slidell
    Not detected
    1 significant inspection deficiency
    C
  • Folsom
    Not detected
    3 significant inspection deficiencies
    C
  • Lewisburg
    Not detected
    1 significant inspection deficiency
    C
County Lead Level — Median 2 ppb
Based on most recent 90th percentile lead tests across all reporting systems
0 ppb5 ppb10 ppb15 ppb
County median: 2 ppb — 13.3% of the federal action level
Systems by Lead Level
Under 5 ppb
3
No Data
8

All Cities in St. Tammany Parish

Slidell Not detected C
Mandeville Not detected A
Covington Not detected D
Eden Isle 1.00 ppb B
Abita Springs 2.00 ppb B
Pearl River Not detected A
Lacombe Not detected B
Madisonville Not detected B
Folsom Not detected C
Lewisburg Not detected C
Sun 2.00 ppb C
Showing 11 cities
No active violations Active violations

About St. Tammany Parish Drinking Water

St. Tammany Parish is served by 11 water systems covering 11 communities. 91% have no open violations.

Of the communities reporting lead results, 3 recorded a detection, with a median of 2.00 ppb — 13% of the federal action level. 8 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 significant deficiencies at 8 of them.

Frequently Asked Questions

Is St. Tammany Parish tap water safe to drink?▼
91% of communities have no open violation. No community has PFAS above the federal limit on record.
What is the lead level in St. Tammany Parish?▼
Among communities with a detection the median is 2.00 ppb, 13% of the 15 ppb action level. 8 reported none detected and 0 reported no result.
How many water systems serve St. Tammany Parish?▼
11 community water systems serve 11 communities here.
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