WaterQ

Iowa Tap Water Quality Rankings 2026: 36th in Nation | WaterQ

Alex Carter
By Alex Carter
Water Quality Researcher ยท Published 2026-06-23

Iowa's public drinking water systems face notable challenges, ranking 36th out of 50 states for water quality. With an average score of 73, the state receives a grade of C overall. This grade reflects the monitoring and safety issues across its water infrastructure, which serves a population of over 2.7 million residents.

Key Findings for Iowa

Reviewing EPA SDWIS data for 2026, here's what defines Iowa's water quality landscape:

  • Due to intensive row-crop and livestock agriculture in the Midwest, runoff from fertilizer and manure can lead to elevated nitrate levels in groundwater source areas.
  • With 335 water systems across the state, monitoring compliance remains an issue, resulting in a total of 11,699 recorded violations.
  • Communities with older infrastructure or private wells in agricultural zones are particularly susceptible to regional groundwater contamination and localized delivery system issues.

Most Common Contaminants in Iowa

Here's what Iowa residents should know about the contaminants most relevant to their water:

Nitrate

Commonly associated with agricultural runoff from fertilizers and animal feeding operations, nitrates frequently affect groundwater systems in the Midwest region.

Disinfection Byproducts

Formed when chlorine used for water treatment reacts with naturally occurring organic matter, these chemicals can accumulate in public distribution networks.

Total Coliform

These bacteria serve as indicators of potential biological contamination, often entering systems through agricultural runoff or aging pipe infrastructure.

Iowa's Best and Worst Cities for Water Quality

To explore how these water quality patterns affect individual communities, please consult our detailed city-by-city breakdown on the Iowa state page. This data shows how local water treatment and testing results vary across different municipalities. Explore the full breakdown on our Iowa water systems page.

What Iowa Residents Should Do

Given Iowa's 36th place ranking, here's what matters most for residents:

  1. Search for your local public water system to review its recent testing and compliance history.
  2. If you rely on a private well in agricultural areas, test your water regularly for nitrates and bacteria.
  3. Consider using a certified water filtration system designed to target contaminants common to your region.
  4. Check the EPA violation database for history on your utility's monitoring and reporting compliance.

Frequently Asked Questions

How does Iowa water quality compare to other states?

Iowa ranks 36th out of 50 states, indicating below-average performance nationally. It has an average water quality score of 73, resulting in a C grade.

What are the most common contaminants in Iowa tap water?

Common regional issues include nitrates from agricultural runoff, disinfection byproducts from treatment processes, and total coliform bacteria. These contaminants are typical for Midwestern agricultural areas with vulnerable groundwater sources.

Is it safe to drink tap water in Iowa?

With a grade of C, Iowa's water meets federal standards in many areas but has experienced 11,699 violations across its 335 systems. Residents are advised to look up their specific local system's compliance record and consider additional home filtration if necessary.

Source: EPA SDWIS 2026 Compliance Data and WaterQ National Database. For more information on our ranking process, visit our state rankings page.