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Counties → New York

Jefferson County, New York

SDWIS compliance plate

Sheet NY045 · Jefferson County 154 sys · 2,971 viol · #484/3254

VIOL-SEVERE · HEALTH-MID · RANK-TOP · PHOTO-FINISH · PFAS-HIGH · SRC-GW · SYS-LARGE · BOOK-FULL

  • VIOL-SEVERE 90.3% flagged
  • HEALTH-MID 29.2% health
  • RANK-TOP #484/3254
  • PHOTO-FINISH ±0.8 pp
  • PFAS-HIGH 75.0% detect
  • SRC-GW GW lead 61%
  • SYS-LARGE 154 systems
  • BOOK-FULL 7/7 fields

Nearest flagged-rate peer: Schoharie County (+ 0.8 pp flagged-rate)

According to EPA SDWIS county population served used on /counties, Jefferson County ranks #484 of 3,254 counties by people served, and #20 of 58 counties in New York. See methodology · corpus placement.

Jefferson County standing, lower-flagged corpus third

Flagged-system rate 90.3% is at or below the corpus lower third (≤ 92.7% flagged) across 2,973 counties with ≥3 SDWIS systems . Health-based share 29.2% is health-based share above the upper third (> 24.5%) . UCMR5 detect rate 75.0% is UCMR5 detect rate above the tested-pool upper third (> 33.3%) . Population served ranks #484 of 3,254 · #20 of 58 in New York.

Flagged-rate neighbourhood around Jefferson County

Lowest/highest poles plus in-state counties nearest Jefferson County on % of SDWIS systems with ≥1 violation. Full ladder: /counties.

0% 20% 40% 60% 80% 100% Niagara · lowest Jefferson · this county Cattaraugus · near Cortland · highest 38.1% 89.3% 90.3% 91% 91.2% 91.8% 100%

Source: EPA SDWIS (county aggregates) As of 2026-05-15

Water Systems

System Name Population Violations PFAS
Fort Drum 34,000 19 Detected
Watertown City 27,861 66 Detected
Leray Town WD 1, 2, 4 7,140 3 Detected
Carthage Village 3,600 56 Clean
Cape Vincent Town WD 1 & 5 2,600 0 -
Sackets Harbor Village 2,200 8 -
Clayton Village 2,100 2 -
Adams Village 2,000 20 -
Can-Am Speedway 2,000 93 -
Alexandria Bay Village 1,900 0 -
Philadelphia Village 1,800 3 -
West Carthage Village 1,734 39 -
Black River Village 1,600 1 -
Cape Vincent Village 1,500 5 -
Stone Mills Museum 1,500 10 -
Ellisburg WD 1, 2 & 3 1,500 4 -
Rutland Town WD 1 1,500 7 -
Brownville Village 1,200 30 -
Dexter Village 1,100 53 -
Adams T WD 1,2,3 (Adams Center) 1,000 6 -
Tiba - Boldt Castle 1,000 0 -
Wellesley Island State Park 1,000 1 -
Pamelia Town WD 4 & 5 1,000 263 -
Theresa Village 950 12 -
Antwerp Village 900 30 -
Thousand Island Park Corp. 900 4 -
Cape Vincent Town WD 3, 4, & 6 770 0 -
Watertown Town WD 3 & 4 & 5 750 27 -
Orleans Town WD 1 (Lafargeville) 750 12 -
Hounsfield WD 2 725 62 -
Henderson Town WD 1,2 700 12 -
Orleans Town WD 2 (Rt 12) 690 0 -
Champion WD 2, 4 & 5 650 11 -
Evans Mills Village 644 22 -
Chaumont Village 625 31 -
Watertown Town WD 1 & 2 600 7 -
Kring Point State Park 600 8 -
Brownville (T) WD #1 600 21 -
Wellesley Island Water Corp. 548 15 -
Northland Estates 540 29 -
Southwick Beach State Park 520 3 -
Glen Park Village 500 19 -
Alexandria Town WD #2 - Redwood 500 12 -
Hounsfield WD 1, 5 480 55 -
Leray Town WD 3 480 0 -
Mannsville Village 450 5 -
Deferiet Village 420 15 -
Champion WD 1 (Great Bend) 400 0 -
Creekstone Farms 400 0 -
Lyme Town WD 2 400 2 -

Compare beyond New York

Lower-flagged peers for Jefferson County

Cross-state counties nearest Jefferson County on flagged-system share (90.3%) and cumulative violation count (2,971). In-state neighbours stay on the compliance plate above.

Similar flagged-system rate

Nearest cross-state counties by % of SDWIS systems with at least one violation on record.

4 peers

Similar violation load

Nearest cross-state counties by cumulative SDWIS violation count (all systems in the county).

4 peers

Read our methodology · Check your water system - how this data is sourced, computed, and verified.

Data sourced from EPA SDWIS and UCMR5 PFAS monitoring data. See our methodology for details. Retrieved and formatted by PlainWater

Every figure on PlainWater is rendered directly from EPA SDWIS drinking-water data, no number is typed in by an editor. This page draws directly on EPA SDWIS data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.