373,875 people (2024 Census estimate, +0.5% since 2020)
706 square miles of land · 530 people per square mile
“Highest” and “lowest” are just order, not grades: a high rank for poverty or hazard losses means more of it. Each figure's source is in its section below.
32 active community water systems list Washtenaw County in the area they serve, reporting 263,484 people served in all (a system that crosses county lines counts its whole population).
| ANN ARBOR surface water · local government · MI0000220 | 123,851 served |
| YPSILANTI COMMUNITY UTILITY AUTHORITY buys surface water · local government · MI0007260 | 53,988 served |
| PITTSFIELD TOWNSHIP buys surface water · local government · MI0005360 | 24,500 served |
| SALINE groundwater · local government · MI0005900 | 9,158 served |
| SCIO TOWNSHIP buys surface water · local government · MI0005977 | 8,500 served |
| MILAN groundwater · local government · MI0004380 | 7,363 served |
| SUPERIOR TOWNSHIP buys surface water · local government · MI0006490 | 6,830 served |
| CHELSEA groundwater · local government · MI0001370 | 5,474 served |
Source: U.S. EPA Safe Drinking Water Information System (SDWIS), active community systems, . Look up any system's violations and test results with EPA's search using its ID.
About 318 people were held in Washtenaw County's jail, in Vera's latest figure (2023), or 126 per 100,000 residents ages 15–64. In 2018 it was about 370.
Source: Vera Institute of Justice, Incarceration Trends (built from federal Bureau of Justice Statistics jail surveys). Counties without their own jail, or that share one, may show no figure.
8 school districts have their office in Washtenaw County. School taxes are usually the largest part of a property tax bill.
Spent $433.3 million — $328.1 million to run schools, about $19,271 per student, plus $87.6 million on buildings and equipment. Money in: $231.3 million local (mostly property tax), $159.1 million state, $11.3 million federal. Long-term debt: $275.9 million.
Spent $95.5 million — $79.2 million to run schools, about $16,263 per student, plus $8.3 million on buildings and equipment. Money in: $50.8 million local (mostly property tax), $55.8 million state, $4.5 million federal. Long-term debt: $100.3 million.
Spent $83.3 million — $69.6 million to run schools, about $18,696 per student, plus $664,000 on buildings and equipment. Money in: $42.1 million local (mostly property tax), $40.2 million state, $16 million federal. Long-term debt: $91.1 million.
Spent $66.8 million — $58.2 million to run schools, about $16,330 per student, plus $1.3 million on buildings and equipment. Money in: $24.6 million local (mostly property tax), $40.1 million state, $7 million federal. Long-term debt: $124.4 million.
Spent $66.6 million — $57 million to run schools, about $16,827 per student, plus $3.7 million on buildings and equipment. Money in: $33.4 million local (mostly property tax), $37.8 million state, $3 million federal. Long-term debt: $95.4 million.
Spent $55.5 million — $37.5 million to run schools, about $16,298 per student, plus $14.2 million on buildings and equipment. Money in: $22.8 million local (mostly property tax), $24.4 million state, $2.3 million federal. Long-term debt: $30.7 million.
Spent $14.3 million — $12.2 million to run schools, about $15,715 per student, plus $248,000 on buildings and equipment. Money in: $10 million local (mostly property tax), $6.1 million state, $1.7 million federal. Long-term debt: $25.9 million.
Spent $17.7 million — $13.9 million to run schools, about $21,322 per student, plus $915,000 on buildings and equipment. Money in: $11.5 million local (mostly property tax), $6.7 million state, $1.7 million federal. Long-term debt: $45.9 million.
Source: U.S. Census Bureau, 2023 Annual Survey of School System Finances. Districts are listed by the county of their main office; some serve neighboring counties too.
Source: County Health Rankings & Roadmaps 2025 (University of Wisconsin Population Health Institute), which gathers federal data (CDC, Census, and others); measures cover different recent years. Blank lines aren't reported for small counties.
Overall risk: Relatively Moderate compared with other U.S. counties. FEMA estimates natural hazards cost Washtenaw County about $92.7 million a year on average in buildings, crops and lives. Ability to bounce back (community resilience): Very High; social vulnerability: Relatively Low.
Source: FEMA National Risk Index (December 2025), expected annual loss. Ratings compare counties nationwide; they're estimates, not predictions.
262 bridges in Washtenaw County: 64 in good condition, 151 fair, and 47 poor (17.9%). “Poor” means a main part — the deck, the beams, or the supports — is rated 4 or lower on the federal 0–9 scale. It doesn't mean unsafe to drive; unsafe bridges are closed.
| US-23NB I-94BL over PACKARD RD · built 1962 | 39,120 vehicles a day |
| US-23SB I-94BL over PACKARD RD · built 1962 | 39,120 vehicles a day |
| US-23 NB over US-23 BR · built 1962 | 39,120 vehicles a day |
| US-23 SB over US-23 BR · built 1962 | 39,120 vehicles a day |
| US-23 NB over HURON RIVER DRIVE · built 1962 | 37,373 vehicles a day |
| US-23 SB over HURON RIVER DRIVE · built 1962 | 37,373 vehicles a day |
Source: Federal Highway Administration, National Bridge Inventory (2025 submission). Includes state, county and city bridges.
Federal grants paid for $867.9 million of work in Washtenaw County in fiscal 2025, about $2,331 per resident — to the county, cities, schools, hospitals, nonprofits and others.
Source: USAspending.gov, grants by place of performance, fiscal 2025 (Oct. 2024 to Sept. 2025). Search it by county to see each award.
From Grants.gov: posted grants listing county governments as eligible, soonest deadline first; research-only and overseas programs left out; list updated 2026-10-13, refreshed weekly. 62 are open in all. Cities, towns, school districts and nonprofits have their own lists there.
Registration deadlines, early voting and polling places for Michigan are on the federal site vote.gov, which links to the state's official election office.
The budget, property tax rates, audits, local officials and offices for Washtenaw County come from the county's own records, which we haven't gathered — not gathered, never hidden. See what a full county site looks like, or ask to have Washtenaw County built: brayden.ozark@gmail.com.
More of Michigan: the state government and every county in Michigan.
Nearby counties: Livingston County (24 mi) · Lenawee County (27 mi) · Monroe County (29 mi) · Jackson County (29 mi) · Wayne County (30 mi) · Ingham County (36 mi).