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Counties → Michigan

Washtenaw County, Michigan

SDWIS compliance plate

Sheet MI161 · Washtenaw County 264 sys · 6,092 viol · #168/3254

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

  • VIOL-SEVERE 90.2% flagged
  • HEALTH-LOW 18.5% health
  • RANK-TOP #168/3254
  • PHOTO-FINISH ±0.0 pp
  • PFAS-MID 30.0% detect
  • SRC-GW GW lead 97%
  • SYS-LARGE 264 systems
  • BOOK-FULL 7/7 fields

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

According to EPA SDWIS county population served used on /counties, Washtenaw County ranks #168 of 3,254 counties by people served, and #5 of 83 counties in Michigan. See methodology · corpus placement.

Washtenaw County standing, lower-flagged corpus third

Flagged-system rate 90.2% is at or below the corpus lower third (≤ 92.7% flagged) across 2,973 counties with ≥3 SDWIS systems . Health-based share 18.5% is health-based share in the middle third (≤ 24.5%) . UCMR5 detect rate 30.0% is UCMR5 detect rate in the tested-pool middle third (≤ 33.3%) . Population served ranks #168 of 3,254 · #5 of 83 in Michigan.

Flagged-rate neighbourhood around Washtenaw County

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

0% 20% 40% 60% 80% 100% Oscoda · lowest Roscommon · near Washtenaw · this county Menominee · highest 52.9% 89.8% 90% 90% 90.2% 90.2% 100%

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

Water Systems

System Name Population Violations PFAS
Ann Arbor 241,868 119 Detected
Ypsilanti Community Utility Authority 53,988 8 Clean
Pittsfield Township 24,500 21 Clean
Saline 9,158 26 Clean
Scio Township 8,500 20 Detected
Milan 7,363 40 Clean
Superior Township 6,830 9 Detected
Chelsea 5,474 24 Clean
Dexter 4,500 93 Clean
Augusta Township 3,907 11 Clean
Trinity Health Ann Arbor 2,500 0 -
Manchester 2,150 9 -
Mdot - Northfield Church, R814 2,008 2 -
Northville Crossing 1,890 36 -
Northfield Estates 1,620 9 -
Mdot - Chelsea Rest Area 1,614 20 -
Loch Alpine Sanitary Authority 1,506 16 -
Ann Arbor Township 1,338 12 -
Thornton Farms 1,188 17 -
Speedway #8876 1,001 35 -
Independence Lake County Park 930 6 -
DNR-Pinckney Rec Area/Silver Lake 900 5 -
DNR-Pinckney Rec Area/Halfmoon Beach 900 3 -
South Arbor Academy 850 74 -
Chestnut Hills 813 12 -
Fca US LLC/Chelsea Prov Grnds 800 22 -
Orchard Grove 725 11 -
River Ridge - Saline 720 0 -
DNR-Pinckney Rec Area/Bruin Lk Cg-Main W 660 3 -
DNR-Waterloo Rec Area-Sugarloaf Cg 660 3 -
Whitmore Lake Elementary 600 35 -
Calvary Bible Church - Ypsilanti 600 10 -
Blue Heron Bay Spray Zone 510 13 -
Whitmore Lake Hs 500 13 -
St. Joseph Catholic - Dexter 500 12 -
Barton Hills 450 46 -
Emerson School - Elementary 450 42 -
Emerson School - Middle 450 16 -
Salem Elementary School 430 15 -
Salem-South Lyon Dist Library 400 10 -
Knox Presbyterian Church 400 26 -
St. Nicholas Church 400 14 -
Christ Our King Lutheran Church-Addition 400 5 -
Christ Our King Lutheran Church - Church 400 0 -
Saline Valley Farms 375 7 -
Huron Valley Tennis Club 350 21 -
Keystone Church 334 22 -
Westbrook Apartments 330 21 -
Huron River Methodist Church - Church 300 60 -
Wide World Sports Center 300 52 -

Compare beyond Michigan

Lower-flagged peers for Washtenaw County

Cross-state counties nearest Washtenaw County on flagged-system share (90.2%) and cumulative violation count (6,092). 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.