PlainWater

Jefferson County, Montana

SDWIS compliance plate

Sheet MT043 · Jefferson County 42 sys · 6,871 viol · #2347/3254

VIOL-SEVERE · HEALTH-LOW · RANK-LOWER · BELOW-PEER · PFAS-NONE · SRC-GW · SYS-MID · BOOK-MOST

  • VIOL-SEVERE 97.6% flagged
  • HEALTH-LOW 18.8% health
  • RANK-LOWER #2347/3254
  • BELOW-PEER 1.3 pp cleaner
  • PFAS-NONE No UCMR5 set
  • SRC-GW GW lead 95%
  • SYS-MID 42 systems
  • BOOK-MOST 6/7 fields

Nearest flagged-rate peer: Lincoln County (+ 1.3 pp flagged-rate)

According to EPA SDWIS county population served used on /counties, Jefferson County ranks #2,347 of 3,254 counties by people served, and #20 of 56 counties in Montana. See methodology · corpus placement.

Jefferson County standing, mid-flagged corpus third

Flagged-system rate 97.6% is in the corpus middle third (≤ 100.0% flagged) across 2,973 counties with ≥3 SDWIS systems . Health-based share 18.8% is health-based share in the middle third (≤ 24.5%) . No UCMR5 tests in this extract for Jefferson County . Population served ranks #2,347 of 3,254 · #20 of 56 in Montana.

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% Powder River · lowest Big Horn · near Jefferson · this county Petroleum · highest 66.7% 95.6% 95.7% 96.3% 97.6% 98.9% 100%

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

Water Systems

System Name Population Violations PFAS
Whitehall Town Of 1,500 689 -
Boulder City Of 1,400 376 -
Jefferson Hills Wua 780 170 -
Lewis and Clark Caverns Visitor Center 615 42 -
Jefferson City South Rest Stop 600 51 -
Montana City School Dist 27 534 66 -
Saddle Mountain Corp Clancy 350 58 -
Clancy Elementary School Dist 01 333 338 -
Forest Park Water Users Association 323 119 -
Pipestone RV Park 286 2 -
Blue Sky Heights Wua Clancy 250 244 -
Montana City Grill and Saloon 250 52 -
Chubbys Bar and Grill 211 361 -
Basin County Water and Sewer Dist 200 754 -
Park Lake Campground 200 59 -
Elkhorn Congregation of Jehovahs Witness 180 3 -
Golden Sunlight Mines Inc 160 536 -
Hangmans Tree Wua 158 55 -
Stoney Brook Village Condominium Assoc 142 125 -
Papa Rays Casino and Hugos Pizza 118 57 -
Jackson Creek Bar and Grille 115 279 -
L and C Caverns State Park Cg 114 15 -
Discovery Kid Zone Montessori 110 0 -
Lewis and Clark Caverns Visitor Contact 106 16 -
Jefferson City North Rest Stop 100 46 -
Lahood Park Cardwell 94 115 -
Elkhorn Health and Rehabilitation LLC 89 257 -
Jefferson Tracts Assoc Inc 80 185 -
Ash Grove Cement Company 75 360 -
Lds Church Whitehall 75 49 -
Cardwell School Dist 16 and 31 63 125 -
Montana City Mercantile Hardware Cafe 56 58 -
Boulder Hot Springs 55 36 -
City Lights Comm Subdi 55 337 -
Merry Widow Health Mine Unapproved 52 14 -
Sunnybrook Acres HOA 50 15 -
Cardwell Campground LLC 50 150 -
Red Cliff Estates HOA 48 119 -
Rocky Mountain Wua 30 177 -
Free Enterprise Radon Health Mine 27 34 -
Alhambra RV Park 27 15 -
Tings Bar 25 312 -

Compare beyond Montana

Mid-flagged peers for Jefferson County

Cross-state counties nearest Jefferson County on flagged-system share (97.6%) and cumulative violation count (6,871). 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.