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Counties → Montana

Yellowstone County, Montana

SDWIS compliance plate

Sheet MT111 · Yellowstone County 116 sys · 16,006 viol · #382/3254

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

  • VIOL-SEVERE 93.1% flagged
  • HEALTH-LOW 6.7% health
  • RANK-TOP #382/3254
  • PHOTO-FINISH ±0.0 pp
  • PFAS-CLEAN 0.0% detect
  • SRC-SW SW lead 55%
  • SYS-MID 116 systems
  • BOOK-FULL 7/7 fields

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

According to EPA SDWIS county population served used on /counties, Yellowstone County ranks #382 of 3,254 counties by people served, and #1 of 56 counties in Montana. See methodology · corpus placement.

Yellowstone County standing, mid-flagged corpus third

Flagged-system rate 93.1% is in the corpus middle third (≤ 100.0% flagged) across 2,973 counties with ≥3 SDWIS systems . Health-based share 6.7% is health-based share at or below the lower third (≤ 10.3%) . UCMR5 detect rate 0.0% is UCMR5 detect rate at or below the tested-pool lower third (≤ 0.0%) . Population served ranks #382 of 3,254 · #1 of 56 in Montana.

Flagged-rate neighbourhood around Yellowstone County

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

0% 20% 40% 60% 80% 100% Powder River · lowest Yellowstone · this county Rosebud · near Petroleum · highest 66.7% 93% 93.1% 93.1% 93.3% 93.5% 100%

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

Water Systems

System Name Population Violations PFAS
Billings City Of 114,000 4 Clean
Co Water Dist of Billings Heights 12,000 11 Clean
Laurel Municipal Water System 6,339 141 Clean
Lockwood Water and Sewer District 5,900 12 Clean
Rocky Mountain College 5,700 9 Clean
Montana State University Billings 2,999 0 Clean
Pioneer Water Service 900 42 -
Worden Ballantine Yellowstone 800 403 -
Meadowlark of Billings LLC 800 52 -
Shepherd Schools 800 42 -
Golden Meadows Subdivision 772 2 -
Fisher Water Service 750 75 -
Hillside Village 650 143 -
Travel Centers of America Truck Plaza 600 17 -
Cherry Creek Estates LLC 600 62 -
Elder Grove Middle School Bldg 6 600 26 -
Windsor Estates 530 126 -
Pryor Creek Water Assn 475 166 -
Elder Grove School Buildings 1 & 2 420 13 -
Custer Rest Area Eastbound 400 31 -
Custer Rest Area Westbound 400 43 -
Sundance Subdivision 378 0 -
Stone Creek Subdivision 378 0 -
Hidden Lake Yellowstone County W and S D 350 643 -
Zoomontana Inc 324 42 -
Emerald View Park 320 31 -
Shiloh Road Development 315 3 -
Shepherd Dollar General Water System 303 0 -
Northwest Water Conditioning Culligan W 300 21 -
Peter Yegen JR Golf Club 300 81 -
Town and Country Dba Market Basket 300 70 -
Camelot Ranch Event Center 300 33 -
New Life Church 250 185 -
Pictograph Cave State Park 250 31 -
Precision Water 250 17 -
Granite Park Water Association 250 50 -
Golden Meadows Subdivision 2nd Cc 245 2 -
Yellowstone Boys and Girls Ranch 240 691 -
Wells Garden Estates 240 280 -
Huntley Yellowstone Co Water and Sewer 230 51 -
Crystal Springs Water System 225 683 -
The Nines Subdivision 220 6 -
Western Ranch Supply 215 33 -
Broadview Town Of 200 358 -
Canyon Creek School District 4 200 66 -
Elder Grove School Building Five 200 35 -
Oak Ridge Estates 200 373 -
Eagle Rock Golf Course 200 151 -
Yellowstone Drag Strip 200 151 -
Go 2 U Water Delivery 200 13 -

Compare beyond Montana

Mid-flagged peers for Yellowstone County

Cross-state counties nearest Yellowstone County on flagged-system share (93.1%) and cumulative violation count (16,006). 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.