PlainWater

Madison County, Montana

SDWIS compliance plate

Sheet MT057 · Madison County 45 sys · 4,771 viol · #2052/3254

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

  • VIOL-SEVERE 100.0% flagged
  • HEALTH-LOW 5.1% health
  • RANK-LOWER #2052/3254
  • PHOTO-FINISH ±0.0 pp
  • PFAS-HIGH 100.0% detect
  • SRC-GW GW lead 100%
  • SYS-MID 45 systems
  • BOOK-FULL 7/7 fields

Nearest flagged-rate peer: Silver Bow County (+ 0 pp flagged-rate)

According to EPA SDWIS county population served used on /counties, Madison County ranks #2,052 of 3,254 counties by people served, and #14 of 56 counties in Montana. See methodology · corpus placement.

Madison County standing, mid-flagged corpus third

Flagged-system rate 100.0% is in the corpus middle third (≤ 100.0% flagged) across 2,973 counties with ≥3 SDWIS systems . Health-based share 5.1% 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 #2,052 of 3,254 · #14 of 56 in Montana.

Flagged-rate neighbourhood around Madison County

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

0% 20% 40% 60% 80% 100% Powder River · lowest Petroleum · highest Mineral · near Custer · near 66.7% 100% 100% 100% 100% 100% 100%

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

Water Systems

System Name Population Violations PFAS
Big Sky County Water and Sewer Dist 363 4,132 97 Detected
Virginia City Water Dept 1,500 162 -
Ennis Town Of 1,400 175 -
Sheridan Town Of 632 123 -
Nevada City 621 68 -
Earthquake Lake Visitor Center 503 33 -
Ennis S Raynolds Pass Rest Area 500 45 -
Andesite Ridge Water System 450 34 -
Twin Bridges Town Of 424 18 -
Galloups Slide Inn Inc 365 145 -
Mt Moonlight Basin 355 55 -
Lower Pioneer Mountain Water System 350 168 -
Palisades Campground 300 38 -
Wade Lake Hilltop Cliff Point Cg 220 21 -
Ennis Hot Springs Business Park Inc 216 91 -
Norris Hot Springs 204 90 -
Valley Garden Golf Village HOA 195 169 -
Ruby Valley Campground 151 63 -
Red Mountain Campground 150 31 -
Madison Valley Baptist Church Unapproved 120 16 -
Madison County Golf Assoc 108 239 -
Town Haul Diner 107 290 -
Ruby Creek Campground 100 23 -
Harrison School District No 23 100 1,139 -
Encampment Trail 100 180 -
Chicks Bar 98 60 -
Indiana Univ Geologic Station 92 62 -
West Fork Cabin Camp 90 49 -
Lake Shore Lodge 75 101 -
Madison River Recreation Area 75 26 -
Lds Church Ennis 70 116 -
Driftwaters Resort 63 223 -
McAllister Lodging 63 47 -
Rainbow Valley Motel 52 138 -
El Western Resort 52 10 -
Lds Church Sheridan 50 7 -
Garnet USA 45 99 -
Madison Double R Ranch 45 21 -
Lone View Ridge Water System 37 7 -
Trapper Springs Campground and Day Use 35 50 -
Magris Talc USA, Inc Yellowstone Mine 32 62 -
Alder School 30 26 -
Dream Drift Flies 30 2 -
Mill Creek Campground 30 52 -
Elkhorn Trailer Court 25 100 -

Compare beyond Montana

Mid-flagged peers for Madison County

Cross-state counties nearest Madison County on flagged-system share (100.0%) and cumulative violation count (4,771). 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
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.