PlainWater
Counties → Wisconsin

Monroe County, Wisconsin

SDWIS compliance plate

Sheet WI081 · Monroe County 97 sys · 2,390 viol · #1133/3254

VIOL-SEVERE · HEALTH-MID · RANK-UPPER · PHOTO-FINISH · PFAS-MID · SRC-GW · SYS-MID · BOOK-FULL

  • VIOL-SEVERE 80.4% flagged
  • HEALTH-MID 34.6% health
  • RANK-UPPER #1133/3254
  • PHOTO-FINISH ±0.1 pp
  • PFAS-MID 33.3% detect
  • SRC-GW GW lead 100%
  • SYS-MID 97 systems
  • BOOK-FULL 7/7 fields

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

According to EPA SDWIS county population served used on /counties, Monroe County ranks #1,133 of 3,254 counties by people served, and #30 of 71 counties in Wisconsin. See methodology · corpus placement.

Monroe County standing, lower-flagged corpus third

Flagged-system rate 80.4% is at or below the corpus lower third (≤ 92.7% flagged) across 2,973 counties with ≥3 SDWIS systems . Health-based share 34.6% is health-based share above the upper third (> 24.5%) . UCMR5 detect rate 33.3% is UCMR5 detect rate in the tested-pool middle third (≤ 33.3%) . Population served ranks #1,133 of 3,254 · #30 of 71 in Wisconsin.

Flagged-rate neighbourhood around Monroe County

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

0% 20% 40% 60% 80% 100% Bayfield · lowest Monroe · this county Columbia · near Milwaukee · highest 52.1% 79.1% 80.4% 80.6% 80.9% 81% 95.3%

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

Water Systems

System Name Population Violations PFAS
Sparta Waterworks 10,025 24 Clean
Fort McCoy North Post 10,000 262 Clean
Tomah Waterworks 9,192 127 Detected
Cashton Waterworks 1,120 48 -
Brookwood High School 700 8 -
Norwalk Waterworks 653 32 -
Warrens Waterworks 540 75 -
Wilton Waterworks 490 40 -
Kendall Waterworks 458 79 -
WI DOT Rest Area 16 Sparta 440 91 -
Oakdale Waterworks 317 11 -
Fort McCoy South Post 250 104 -
Fort McCoy Range 34 200 26 -
Ambassador Baptist Church 200 42 -
St Michaels Catholic Church 150 7 -
Vpp Group LLC 150 13 -
Cortland Acres 145 12 -
Western Technical College-Sparta 135 2 -
Wyeville Elementary School 130 14 -
WI DNR Mill Bluff Beach 125 51 -
WI DNR Mill Bluff Office 125 55 -
Rockland Industrial Products 120 0 -
Fort McCoy Range 2 100 8 -
Monroe Co McMullen Park-Camping East 100 8 -
Hiawatha Golf Club 4 100 9 -
Monroe Co McMullen Park-Camping West 100 14 -
Monroe Co McMullen Park-Fish House 100 14 -
J&m Flying Wheels 100 11 -
Evergreen Supper Club 100 0 -
Fort McCoy Range 32 100 4 -
Monroe Co McMullen Park-Bathhouse 100 17 -
Fort McCoy Range 101 100 4 -
Fort McCoy Range 18 100 8 -
Smart Sand Inc - Main Office 97 0 -
Immanuel Lutheran Church 80 6 -
Ocean Spray Cranberry Inc 75 26 -
Almost Home Bar & Grill 75 31 -
St Matthews Lutheran Church 75 0 -
Monkeys Roost 75 32 -
Club Oasis 75 3 -
Covia Holdings Corporation 70 8 -
Big Dans Longbranch 60 42 -
Backwater Bar and Grill 50 148 -
Duffys Roadhouse 50 59 -
St Johns Lutheran Church 50 21 -
First Cong Ch of Leon 50 26 -
Leon Country Tavern 50 10 -
WI DNR Elroy Sparta Bike Trail - Sparta Campground W 50 28 -
Open Door Baptist Church 50 38 -
Cataract Methodist Church 40 21 -

Compare beyond Wisconsin

Lower-flagged peers for Monroe County

Cross-state counties nearest Monroe County on flagged-system share (80.4%) and cumulative violation count (2,390). 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.