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Counties → Pennsylvania

Chester County, Pennsylvania

SDWIS compliance plate

Sheet PA029 · Chester County 276 sys · 47,248 viol · #232/3254

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

  • VIOL-SEVERE 98.6% flagged
  • HEALTH-LOW 5.0% health
  • RANK-TOP #232/3254
  • PHOTO-FINISH ±0.1 pp
  • PFAS-HIGH 100.0% detect
  • SRC-GW GW lead 93%
  • SYS-LARGE 276 systems
  • BOOK-FULL 7/7 fields

Nearest flagged-rate peer: Dauphin County (+ 0.1 pp flagged-rate)

According to EPA SDWIS county population served used on /counties, Chester County ranks #232 of 3,254 counties by people served, and #11 of 68 counties in Pennsylvania. See methodology · corpus placement.

Chester County standing, mid-flagged corpus third

Flagged-system rate 98.6% is in the corpus middle third (≤ 100.0% flagged) across 2,973 counties with ≥3 SDWIS systems . Health-based share 5.0% is health-based share at or below the lower third (≤ 10.3%) . UCMR5 detect rate 100.0% is UCMR5 detect rate above the tested-pool upper third (> 33.3%) . Population served ranks #232 of 3,254 · #11 of 68 in Pennsylvania.

Flagged-rate neighbourhood around Chester County

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

0% 20% 40% 60% 80% 100% Greene · lowest Chester · this county Westmoreland · near Sullivan · highest 66.7% 98.3% 98.6% 98.6% 98.8% 98.8% 100%

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

Water Systems

System Name Population Violations PFAS
Aqua PA West Chester 48,600 188 Detected
PA American Royersford 46,847 146 Detected
PA American Coatesville 36,960 81 Detected
Aqua PA Uwchlan 35,518 237 Detected
Phoenixville Water Dept 16,599 502 Detected
Downingtown Water Authority 9,900 248 Detected
Aqua PA Friendship 8,800 216 Detected
Aqua PA Spring Run 8,151 395 Detected
Kennett Square Mun Water Works 6,328 653 Detected
Oxford Borough 5,280 349 Detected
London Grove Twp Mun Auth 4,770 117 Detected
Octorara Area School District 3,100 205 -
Wawa Food Market 289 2,925 18 -
North Coventry Water System 2,907 132 -
Honey Brook Boro Water 2,892 520 -
West Grove Borough 2,873 429 -
PA American Phoenixville 2,661 7 -
Coatesville Veterans Adm Hosp 2,000 292 -
Ojrsd Owen J Roberts MS and Hs 1,750 196 -
Elverson Water Company 1,641 322 -
Marsh Creek State Park 1,630 108 -
Aqua PA Honeybrook 1,600 39 -
Wawa Food Store #88 1,425 38 -
Borough of Atglen 1,406 146 -
Turkey Hill Minit Market #82 1,400 89 -
Borough of Avondale 1,108 420 -
Peter J. Camiel Service Plaza 1,100 247 -
Loch Nairn Farm 1,000 114 -
Tel Hai Retirement Community 930 118 -
Ridglea 900 367 -
Turkey Hill #168 900 48 -
Westtown School 900 651 -
Ojrsd French Creek Elem Sch 700 357 -
Aqua PA East Pikeland 675 0 -
Brandywine Wallace Elem 600 264 -
Springton Manor Elementary 600 75 -
Indian Run Village MHP 550 121 -
Avon Grove Charter School 549 128 -
Ojrsd E Vincent Elem School 538 12 -
Ojrsd N Coventry Elem School 530 9 -
Camp Saginaw 530 47 -
Casd Kings Highway Elem Sch 521 268 -
Turkey Hill Minit Market #177 500 2 -
Aqua PA Superior Suburbia Ctr 500 1,174 -
Willowdale Town Center 500 166 -
Chadds Ford Elementary School 500 278 -
Chaddsford Winery 500 12 -
Nottingham Manor M H Court 473 3,266 -
Appleville Mobile Home Park 461 899 -
Spring Run Estates WTP 450 87 -

Compare beyond Pennsylvania

Mid-flagged peers for Chester County

Cross-state counties nearest Chester County on flagged-system share (98.6%) and cumulative violation count (47,248). 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.