States → Iowa
State profile · EPA SDWIS + UCMR5
Iowa Drinking Water Quality
1,795 public water systems serve 3,114,444 people across Iowa, with every Safe Drinking Water Act violation and UCMR5 PFAS result on record.
- 1,795
- Water systems
- 138,271
- Total violations
- 95.2%
- Systems w/ a violation
- 83.6%
- PFAS detection rate
The verdict
Across Iowa, 1,708 of 1,795 water systems (95.2%) carry at least one EPA violation, and 127 of 152 UCMR5-tested systems show PFAS.
- 138,271
- Total EPA violations on record
- 20%
- Health-based (MCL / treatment)
- 95.2%
- Systems with ≥1 violation
- 83.6%
- UCMR5 PFAS detection rate
Water Systems
1,795
Total Violations
138,271
Violation Rate
95.2%
PFAS Detection
83.6%
127 of 152 tested
Violation Composition
How Iowa's 138,271 violations break down by type, per EPA SDWIS classification.
Health-based (27,946) Monitoring/Reporting (110,325)
| Metric | Value | Share |
|---|---|---|
| Public water systems | 1,795 | - |
| Population served | 3,114,444 | - |
| Total violations | 138,271 | 100% |
| Health-based violations | 27,946 | 20.2% |
| Systems with violations | 1,708 | 95.2% |
| PFAS detection rate | 127 of 152 | 83.6% |
Health-based violations indicate the contaminant exceeded an EPA Maximum Contaminant Level (MCL) or treatment-technique requirement. Monitoring/reporting violations indicate procedural issues (missed tests, late reports) - not necessarily a contamination event.
Largest Water Systems
Des Moines Water Works
Des Moines, IA · 246,055 served
Iowa-American Wtr Co-Davenport
Davenport, IA · 147,720 served
Cedar Rapids Water Department
Cedar Rapids, IA · 141,831 served
Sioux City Water Supply
Sioux City, IA · 85,791 served
Ankeny, City Of
Ankeny, IA · 76,207 served
Waterloo Water Works
Waterloo, IA · 69,504 served
Iowa City Water Department
Iowa City, IA · 68,753 served
West Des Moines Water Works
West Des Moines, IA · 68,723 served
Council Bluffs Water Works
Council Bluffs, IA · 64,447 served
Dubuque Water Works
Dubuque, IA · 59,667 served
Ames Water Treatment Plant
Ames, IA · 55,177 served
Urbandale Water Utility
Urbandale, IA · 45,605 served
Isu
Ames, IA · 42,000 served
Marion Municipal Water Dept
Marion, IA · 41,623 served
Cedar Falls Municipal Water Utilities
Cedar Falls, IA · 40,713 served
IA Regional Utilities Assoc (Waverly)
Newton, IA · 37,820 served
Rathbun Regional Water Assn (Rathbun)
Centerville, IA · 33,000 served
Waukee Water Supply
Waukee, IA · 31,823 served
Marshalltown Water Works
Marshalltown, IA · 27,591 served
Mason City Water Department
Mason City, IA · 27,338 served
Most Violations
#1 Corydon Water Supply Corydon
1,441 #2 Montipark LLC Seattle
931 #3 Corning Muni Water Department Corning
893 #4 Churdan Water Supply Churdan
875 #5 Midway Water and Lighting Hiawatha
841 #6 Aunt Dharma's Sandbar on the Wapsi LLC Troy Mills
832 #7 Bloomfield Muni Water Dept Bloomfield
793 #8 Gallery Acres West Tipton
679 #9 Stockyard Garnavillo
678 #10 Mason City Water Department Mason City
647 #11 Mount Ayr Water Treatment Plant Mount Ayr
611 #12 Big Rock Country Club Fayette
598 #13 Chariton Municipal Water Works Chariton
590 #14 Prairie View Estates Assoc Johnson Cnty Iowa City
544 #15 Cliffs Place Inc Waverly
540 Counties in Iowa
Polk
38 systems · 552,627 served
· 1,563 violations
Linn
83 systems · 224,711 served
· 8,540 violations
Scott
77 systems · 178,285 served
· 5,956 violations
Johnson
125 systems · 167,742 served
· 10,912 violations
Black Hawk
19 systems · 161,225 served
· 824 violations
Story
21 systems · 121,108 served
· 1,299 violations
Woodbury
32 systems · 99,461 served
· 1,715 violations
Dubuque
75 systems · 92,945 served
· 5,981 violations
Pottawattamie
33 systems · 85,108 served
· 2,294 violations
Dallas
22 systems · 73,706 served
· 1,211 violations
Decatur
6 systems · 59,279 served
· 574 violations
Warren
12 systems · 57,255 served
· 571 violations
Des Moines
11 systems · 43,192 served
· 768 violations
Clinton
28 systems · 40,325 served
· 1,996 violations
Cerro Gordo
34 systems · 39,879 served
· 3,147 violations
Muscatine
38 systems · 39,113 served
· 2,700 violations
Sioux
16 systems · 38,650 served
· 698 violations
Lee
7 systems · 35,911 served
· 708 violations
Marshall
12 systems · 33,539 served
· 591 violations
Washington
25 systems · 33,305 served
· 2,007 violations
Boone
13 systems · 32,746 served
· 824 violations
Webster
30 systems · 32,620 served
· 2,274 violations
Marion
14 systems · 30,305 served
· 760 violations
Wapello
5 systems · 27,531 served
· 214 violations
Jasper
11 systems · 26,205 served
· 526 violations
Tama
13 systems · 25,305 served
· 733 violations
Mahaska
4 systems · 24,159 served
· 390 violations
Carroll
13 systems · 19,807 served
· 1,060 violations
Clay
6 systems · 19,361 served
· 324 violations
Benton
24 systems · 19,032 served
· 1,562 violations
Showing top 30 of 99 counties.
Drinking Water Guides
Frequently Asked Questions
How many water systems are in Iowa? ▼
Iowa has 1,795 public water systems serving approximately 3,114,444 people. These include community water systems, non-transient non-community systems, and transient non-community systems regulated under the Safe Drinking Water Act.
How many drinking water violations are in Iowa? ▼
Iowa has 138,271 total drinking water violations on record, with 27,946 classified as health-based violations. 95.2% of water systems in the state have at least one violation.
Has PFAS been found in Iowa drinking water? ▼
Of 152 water systems tested for PFAS in Iowa, 127 had PFAS detected, a 83.6% detection rate. PFAS are persistent "forever chemicals" that do not break down in the environment.
What is the violation rate for Iowa water systems? ▼
Iowa's violation rate is 95.2%. This measures the percentage of public water systems that have at least one recorded violation in the EPA SDWIS database, including both health-based and monitoring/reporting violations.
Where does this Iowa water data come from? ▼
All drinking water data comes from the EPA Safe Drinking Water Information System (SDWIS) and the UCMR5 PFAS monitoring program. SDWIS is the federal database that tracks compliance for all public water systems regulated under the Safe Drinking Water Act.
Data Sources & Methodology
Drinking water violation data from the EPA Safe Drinking Water Information System (SDWIS). PFAS testing data from the UCMR5 monitoring program. SDWIS tracks all public water systems regulated under the Safe Drinking Water Act.
Read our methodology - how this data is sourced, computed, and verified.
Related
Data sourced from EPA SDWIS and UCMR5 PFAS monitoring data. See our methodology for details. Retrieved and formatted by PlainWater Editorial
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.