Loading water data...
Not health advice. Contact your local water utility for concerns.
Data from EPA Water Quality Reports. For official information, contact your water utility or health department.
Water quality data for 5 cities serving 466,723 residents
Polk County in Iowa has an average water quality score of 100/100 (Grade A) based on analysis of 5 municipal water systems. The county's water systems serve approximately 466,723 residents.
Overall, Polk County demonstrates good water quality standards. 5 of 5 cities exceed the county average, with Johnston leading with a score of 100/100.
5 cities ranked by water quality score
| Rank | City | Score | Grade | Population |
|---|---|---|---|---|
| 1 | Des Moines | 100 | A | 246,055 |
| 2 | Ankeny | 100 | A | 76,207 |
| 3 | West Des Moines | 100 | A | 73,959 |
| 4 | Urbandale | 100 | A | 45,605 |
| 5 | Johnston | 100 | A | 24,897 |
Real EPA readings across county water systems (lead: latest 90th percentile; PFAS: UCMR5 2023–2026; others: 2012–2019 averages)
| Contaminant | Avg Level | Max Level | EPA Limit | % of Limit | Cities |
|---|---|---|---|---|---|
| TTHM (2012–2019 avg) | 50.8 ug/L | 60.75 ug/L | 80 ug/L | 63.5% | 2 |
| HAA5 (2012–2019 avg) | 10.5 ug/L | 11.75 ug/L | 60 ug/L | 17.5% | 2 |
| Arsenic (2012–2019 avg) | 1.5 ug/L | 1.5 ug/L | 10 ug/L | 15% | 1 |
| Lead (90th percentile) | 0 ppb | 0 ppb | 15 ppb | 0% | 5 |
| PFAS (PFOA/PFOS max, UCMR5) | 0 ppt | 0 ppt | 4 ppt | 0% | 5 |
Recent violations across county water systems
Health-based: Treatment technique — Treatment Technique (SWTR and GWR) - Surface Water Treatment Rule
4/30/2017
Monitoring & reporting — Monitoring of Treatment (SWTR-Filter) - Long Term 2 Enhanced Surface Water Treatment Rule
10/31/2018
Water quality in Polk County, Iowa reflects the region's unique combination of water sources, treatment infrastructure, and environmental factors. Our comprehensive analysis examines 5 municipal water systems serving a combined population of over 466,723 residents.
The county shows strong water quality performance, with scores ranging from 100/100 in Des Moines to 100/100 in Johnston. This 0-point spread indicates relatively consistent water quality standards across municipal systems.
The most prevalent contaminants detected across Polk County water systems include TTHM (2012–2019 avg), HAA5 (2012–2019 avg), Arsenic (2012–2019 avg). At least one reading averages above 50% of its EPA limit across the county's systems, worth attention from residents and utilities.
Polk County's water quality is generally good. Residents can feel confident in their tap water quality, though those with specific health concerns or sensitivity to certain contaminants may still benefit from filtration. Regular review of your city's annual Consumer Confidence Report is recommended.
Polk County has an average water quality score of 100/100 (Grade A) based on analysis of 5 municipal water systems serving 466,723 residents.
Johnston has the highest water quality score in Polk County at 100/100. View the detailed report for Johnston.
Most cities in Polk County have water that meets EPA standards. However, a water filter can provide additional protection and improve taste. The need depends on your specific city and any personal health considerations.
Click on any city in the rankings table above to view its detailed water quality report, including contaminant levels, EPA compliance history, and filter recommendations.