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Counties → Maryland

Frederick County, Maryland

SDWIS compliance plate

Sheet MD021 · Frederick County 220 sys · 3,555 viol · #317/3254

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

  • VIOL-SEVERE 71.4% flagged
  • HEALTH-MID 41.9% health
  • RANK-TOP #317/3254
  • PHOTO-FINISH ±0.5 pp
  • PFAS-HIGH 75.0% detect
  • SRC-GW GW lead 92%
  • SYS-LARGE 220 systems
  • BOOK-FULL 7/7 fields

Nearest flagged-rate peer: Caroline County (+ 0.5 pp flagged-rate)

According to EPA SDWIS county population served used on /counties, Frederick County ranks #317 of 3,254 counties by people served, and #6 of 24 counties in Maryland. See methodology · corpus placement.

Frederick County standing, lower-flagged corpus third

Flagged-system rate 71.4% is at or below the corpus lower third (≤ 92.7% flagged) across 2,973 counties with ≥3 SDWIS systems . Health-based share 41.9% 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 #317 of 3,254 · #6 of 24 in Maryland.

Flagged-rate neighbourhood around Frederick County

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

0% 20% 40% 60% 80% 100% Baltimore city · lowest Caroline · near Queen Anne's · near Kent · highest 38.5% 71.4% 71.9% 72.7% 77% 77.3% 96.6%

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

Water Systems

System Name Population Violations PFAS
New Design - Frederick County 74,911 28 Detected
City of Frederick 54,000 11 Detected
Town of Walkersville 8,440 34 Clean
Fort Detrick 7,900 109 Detected
City of Brunswick 7,312 17 Clean
Town of Thurmont 6,200 99 Detected
Town of Middletown 4,288 37 Detected
Fountaindale South 2,610 4 -
McDonalds 2,499 26 -
Town of Emmitsburg 2,400 66 -
I-70 Rest Areas (Eastside and Westside) 2,000 0 -
Mount Saint Marys University 1,900 166 -
Linganore High School 1,722 22 -
Knolls of Windsor 1,553 0 -
Town of Myersville 1,516 21 -
Waterside 1,509 0 -
Sam Hill Estates 1,036 2 -
Cambridge Farms 953 0 -
Dunkin Donuts -Jefferson 908 0 -
Cloverhill 3 - Consecutive to Md0100015 888 39 -
Town of Woodsboro 846 75 -
Mountaindale Convenience Store # 2 812 0 -
Mary Miller LLC 780 0 -
Catoctin Mountain Nat. Park-Misty Mount 668 1 -
Kemptown Elementary 623 31 -
Jefferson Market 606 13 -
Drcc-Damascus Road Community Church 600 0 -
Mountain View Community Church 600 16 -
Cunningham Falls - Houck Area 577 0 -
Catoctin Wildlife Preserve & Zoo 575 17 -
7- Eleven - (Gasmart of Frederick) 500 1 -
Urbana Convenience Shop (Exxon) 500 4 -
Yellow Springs Elementary 486 36 -
Liberty Elementary 466 20 -
St. Ignatius of Loyola Catholic Church 455 0 -
7-Eleven- Thurmont#28960 450 15 -
Bar T Mountainside 450 7 -
Christian Life Center 450 3 -
Green Meadows Petting Farm 400 0 -
Urbana Vfd 355 3 -
Carroll Fuel (Urbana Pike) 350 14 -
Copperfield 338 0 -
Summit Lake Camp 316 1 -
Glenn Ellen Farm 300 0 -
Country Meadows of Frederick 295 22 -
Camp Airy, Lil Strauss Found 294 0 -
Lewistown Elementary 267 23 -
Frederick Baptist Church & School 267 10 -
White Rock 256 7 -
Skycroft Baptist Conerence Center 250 7 -

Compare beyond Maryland

Lower-flagged peers for Frederick County

Cross-state counties nearest Frederick County on flagged-system share (71.4%) and cumulative violation count (3,555). 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.