516,185 people (2024 Census estimate, +4.7% since 2020)
573 square miles of land · 901 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.
38 active community water systems list Polk County in the area they serve, reporting 565,553 people served in all (a system that crosses county lines counts its whole population).
| DES MOINES WATER WORKS buys surface water · local government · IA7727031 | 246,055 served |
| ANKENY, CITY OF buys surface water · local government · IA7709053 | 76,207 served |
| WEST DES MOINES WATER WORKS buys surface water · local government · IA7785007 | 73,959 served |
| URBANDALE WATER UTILITY buys surface water · local government · IA7780042 | 45,605 served |
| JOHNSTON MUNICIPAL WATER SUPPLY buys surface water · local government · IA7740011 | 24,897 served |
| ALTOONA WATER SUPPLY groundwater · local government · IA7707030 | 22,436 served |
| CLIVE WATER DEPARTMENT buys surface water · local government · IA7720051 | 20,277 served |
| GRIMES WATER SUPPLY groundwater · local government · IA7736011 | 17,997 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 952 people were held in Polk County's jail, in Vera's latest figure (2024), or 286 per 100,000 residents ages 15–64. In 2019 it was about 1,027.
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.
10 school districts have their office in Polk County. School taxes are usually the largest part of a property tax bill.
Spent $562.6 million — $469.9 million to run schools, about $15,286 per student, plus $52.8 million on buildings and equipment. Money in: $176.2 million local (mostly property tax), $316.5 million state, $91.1 million federal. Long-term debt: $138.1 million.
Spent $199.8 million — $154.6 million to run schools, about $12,127 per student, plus $36 million on buildings and equipment. Money in: $95.3 million local (mostly property tax), $105.3 million state, $7.6 million federal. Long-term debt: $139.1 million.
Spent $195.9 million — $128.4 million to run schools, about $13,914 per student, plus $56.3 million on buildings and equipment. Money in: $91 million local (mostly property tax), $66.4 million state, $12 million federal. Long-term debt: $73.7 million.
Spent $104.4 million — $92 million to run schools, about $12,286 per student, plus $3.2 million on buildings and equipment. Money in: $66.4 million local (mostly property tax), $60.1 million state, $5.3 million federal. Long-term debt: $55.5 million.
Spent $148 million — $93.1 million to run schools, about $12,583 per student, plus $48.5 million on buildings and equipment. Money in: $50.2 million local (mostly property tax), $65.3 million state, $7.6 million federal. Long-term debt: $116.8 million.
Spent $84.1 million — $54 million to run schools, about $12,546 per student, plus $23.9 million on buildings and equipment. Money in: $41 million local (mostly property tax), $29.2 million state, $4.1 million federal. Long-term debt: $101.5 million.
Spent $41 million — $31.3 million to run schools, about $11,454 per student, plus $7.4 million on buildings and equipment. Money in: $17 million local (mostly property tax), $22.1 million state, $1.9 million federal. Long-term debt: $52.1 million.
Spent $37.2 million — $25.8 million to run schools, about $11,506 per student, plus $9 million on buildings and equipment. Money in: $15.1 million local (mostly property tax), $17.3 million state, $1.4 million federal. Long-term debt: $46.5 million.
And 2 more.
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 Polk County about $137.6 million a year on average in buildings, crops and lives. Ability to bounce back (community resilience): Very High; social vulnerability: Very Low.
Source: FEMA National Risk Index (December 2025), expected annual loss. Ratings compare counties nationwide; they're estimates, not predictions.
548 bridges in Polk County: 319 in good condition, 195 fair, and 34 poor (6.2%). “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.
| FLEUR DR over OLD UP RR & SW 22ND · built 1936 | 15,634 vehicles a day |
| SW 9TH ST over CHERRY RR MLK PKWY · built 1967 | 14,108 vehicles a day |
| SW 9TH ST over RACCOON RIVER & TRAIL · built 1967 | 12,809 vehicles a day |
| SE 6TH ST over DES MOINES RIVER · built 1976 | 7,911 vehicles a day |
| SW 8TH ST over RR CHERRY MLK JR PKWY · built 1967 | 6,875 vehicles a day |
| SE 5TH ST over YEADER CREEK · built 1976 | 4,717 vehicles a day |
Source: Federal Highway Administration, National Bridge Inventory (2025 submission). Includes state, county and city bridges.
Federal grants paid for $1.5 billion of work in Polk County in fiscal 2025, about $3,113 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 Iowa 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 Polk 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 Polk County built: brayden.ozark@gmail.com.
More of Iowa: the state government and every county in Iowa.
Nearby counties: Dallas County (24 mi) · Warren County (24 mi) · Story County (25 mi) · Jasper County (27 mi) · Boone County (31 mi) · Madison County (34 mi).