States › New York › Suffolk County

Suffolk County, NY Water Quality

Water quality data for 3 public water systems serving Suffolk County, New York — based on EPA SDWIS enforcement records, lead testing results, and health-based violation history.

📅 2026 Report 🔄 Data updated 2026 Q2 📍 3 water systems · 19 cities
⚠️
Caution Advised — Some Systems Need Attention

Some systems have elevated lead levels or active violations. Check your specific city below.

C

Suffolk County Earns a C

Suffolk County: 19 communities across 3 water systems. 100.0% have no open violations.

  • Median lead where detected: 1.27 ppb
  • 19 communities with a lead detection, 0 reporting none detected
  • 16 communities with PFAS above the federal limit
  • 0 with significant inspection deficiencies
  • 100.0% of communities have no open violations
1.27 ppb
Median Lead Level
County-wide, 90th percentile
3
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
  • Riverhead
    2.15 ppb
    1 health-based violation since 2015
    A
  • Calverton
    2.15 ppb
    1 health-based violation since 2015
    A
  • Shelter Island
    1.33 ppb
    Copper above the 1,300 ppb action level
    B
  • Brookhaven
    1.27 ppb
    PFAS above the limit at 10 of 238 sampling points
    C
  • Islip
    1.27 ppb
    PFAS above the limit at 10 of 238 sampling points
    C
⚠ Needs Attention
  • Brookhaven
    1.27 ppb
    PFAS above the limit at 10 of 238 sampling points
    C
  • Islip
    1.27 ppb
    PFAS above the limit at 10 of 238 sampling points
    C
  • Babylon
    1.27 ppb
    PFAS above the limit at 10 of 238 sampling points
    C
  • Huntington
    1.27 ppb
    PFAS above the limit at 10 of 238 sampling points
    C
  • Smithtown
    1.27 ppb
    PFAS above the limit at 10 of 238 sampling points
    C
County Lead Level — Median 1.27 ppb
Based on most recent 90th percentile lead tests across all reporting systems
0 ppb5 ppb10 ppb15 ppb
County median: 1.27 ppb — 8.5% of the federal action level
Systems by Lead Level
Under 5 ppb
19

All Cities in Suffolk County

Brookhaven 1.27 ppb C
Islip 1.27 ppb C
Babylon 1.27 ppb C
Huntington 1.27 ppb C
Smithtown 1.27 ppb C
Southampton 1.27 ppb C
Riverhead 2.15 ppb A
Commack 1.27 ppb C
Holbrook 1.27 ppb C
Hauppauge 1.27 ppb C
East Hampton 1.27 ppb C
Lake Ronkonkoma 1.27 ppb C
Southold 1.27 ppb C
Fort Salonga 1.27 ppb C
Calverton 2.15 ppb A
Sag Harbor 1.27 ppb C
Eastport 1.27 ppb C
Fire Island 1.27 ppb C
Shelter Island 1.33 ppb B
Showing 19 cities
No active violations Active violations

About Suffolk County Drinking Water

Suffolk County is served by 3 water systems covering 19 communities. No community here has an open violation on record.

Of the communities reporting lead results, 19 recorded a detection, with a median of 1.27 ppb — 8% of the federal action level. 0 reported none detected, which means below the laboratory limit rather than an absence of lead.

16 of 19 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 Suffolk County tap water safe to drink?▼
No community in Suffolk County has an open violation on record. 16 of 19 have PFAS above the federal limit, which is the main open concern.
What is the lead level in Suffolk County?▼
Among communities with a detection the median is 1.27 ppb, 8% of the 15 ppb action level. 0 reported none detected and 0 reported no result.
How many water systems serve Suffolk County?▼
3 community water systems serve 19 communities here.
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