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Counties → New Jersey

Mercer County, New Jersey

SDWIS compliance plate

Sheet NJ021 · Mercer County 97 sys · 7,431 viol · #217/3254

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

  • VIOL-SEVERE 94.8% flagged
  • HEALTH-LOW 9.9% health
  • RANK-TOP #217/3254
  • PHOTO-FINISH ±0.3 pp
  • PFAS-HIGH 57.1% detect
  • SRC-GW GW lead 95%
  • SYS-MID 97 systems
  • BOOK-FULL 7/7 fields

Nearest flagged-rate peer: Warren County (+ 0.3 pp flagged-rate)

According to EPA SDWIS county population served used on /counties, Mercer County ranks #217 of 3,254 counties by people served, and #13 of 21 counties in New Jersey. See methodology · corpus placement.

Mercer County standing, mid-flagged corpus third

Flagged-system rate 94.8% is in the corpus middle third (≤ 100.0% flagged) across 2,973 counties with ≥3 SDWIS systems . Health-based share 9.9% is health-based share at or below the lower third (≤ 10.3%) . UCMR5 detect rate 57.1% is UCMR5 detect rate above the tested-pool upper third (> 33.3%) . Population served ranks #217 of 3,254 · #13 of 21 in New Jersey.

Flagged-rate neighbourhood around Mercer County

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

0% 20% 40% 60% 80% 100% Ocean · lowest Gloucester · near Warren · near Hudson · highest 91.1% 94.3% 94.5% 94.8% 95.1% 95.6% 100%

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

Water Systems

System Name Population Violations PFAS
Trenton Water Works 217,000 412 Clean
Aqua NJ - Hamilton Square 39,128 84 Detected
East Windsor Mua 25,000 92 Clean
Aqua NJ - Lawrence 8,655 346 Detected
Hightstown Water Department 5,400 129 Clean
Pennington Shop-Rite 3,663 36 Detected
Pennington W Dept 2,600 648 -
Hopewell Boro W Dept 2,035 478 -
Bent Iron Brewery 1,201 3 -
Lawrenceville School 1,200 162 -
Terhune Orchards 1,025 168 -
Corner Stone Court 940 26 -
Timberlane Middle School 901 213 -
Mercer County Correctional Center 860 308 -
Stacys Cream King 800 66 -
Washington Crossing Sp-Interpretive Ctr 720 54 -
Washington Crossing Sp Knox Grove 720 98 -
Washington Cross Sp Green Grove Pic Area 720 96 -
Washington Crossing Sp Visitors Center 720 45 -
Washington Crossing State Pk Stone Barn 720 80 -
Washington Crossing State Pk Day Use Trl 720 53 -
The Pennington School 565 113 -
Bear Tavern School 555 73 Detected
Hopewell Valley Golf Clu 548 36 -
Hamilton YMCA at Sawmill Road 498 8 -
Wildflowers 362 18 -
Washington Crossing Park Estates 356 120 -
Princeton Community Church 305 10 -
Robbinsville Twp - Newtown Village 300 14 -
Unitarian Universalist C 271 17 -
Tree Farm Village 230 58 -
Pennington Cleaners 215 30 -
Golden Nugget Antique Flea Mkt 205 28 -
Little League of Hopewell Twp 200 35 -
Princeton RD Professiona 165 6 -
Professor's Hard Cider 162 2 -
Goddard School - West Windsor 155 2 -
Kooltronic Inc 140 97 -
Titusville Marketplace 135 0 -
Pennington Montessori School 133 28 -
Saint Peter Lutheran Church 125 21 -
Offices at Pennington Point 125 117 -
Its Nutts 120 6 -
Titusville Academy Princeton 116 32 -
Patriots Crossing Restaurant 112 53 -
Princeton Child Developmnt Ins 110 63 -
Marcos Pizza 104 43 -
Hillbilly Hall, Inc. 104 68 -
Revere Restaurant 100 27 -
Mercer Professional Center @ Penn 100 39 -

Compare beyond New Jersey

Mid-flagged peers for Mercer County

Cross-state counties nearest Mercer County on flagged-system share (94.8%) and cumulative violation count (7,431). 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.