Water in Iowa.
Iowa's intensive corn and soy agriculture drives the worst nitrate exposure in the country. Des Moines Water Works has sued upstream agricultural drainage districts over nitrate runoff. Groundwater wells across rural Iowa frequently exceed EWG nitrate guidelines.
Des Moines Water Works' nitrate lawsuit against upstream farms remains a landmark in U.S. agricultural water policy.
How Iowa regulates drinking water.
Federal SDWA primacy. No state MCLs stricter than federal for nitrate (remains 10 ppm federal MCL). State has been politically resistant to enforceable agricultural runoff limits.
Iowa Department of Natural Resources — Water Supply Engineering
Iowa's water history, in order.
The contamination events, regulatory shifts, and major settlements that define how this state thinks about drinking water today.
- 2015
Des Moines Water Works sues three upstream drainage districts over nitrate runoff.
- 2017
Federal court dismisses Des Moines lawsuit, citing agricultural exemption.
- 2022
Nitrate-related drinking-water complaints reach record levels in Cedar Rapids and Des Moines.
The actual water you drink.
The physical rivers, aquifers, lakes, and reservoirs that feed Iowa's public water systems. Source quality is the foundation of tap quality — and where the long-term protection fights happen.
- riverDes Moines River
Des Moines metro.
- riverIowa + Cedar Rivers
Cedar Rapids.
- aquiferJordan Aquifer System
Eastern IA bedrock aquifer.
- riverMississippi River
Quad Cities.
Source-water mix
~80% groundwater, ~20% surface water
Major cities served
Des Moines · Cedar Rapids · Davenport · Sioux City · Iowa City
Who actually serves the water.
The largest public water systems in Iowa by population served. Click your ZIP after to see the full live EWG report for your specific utility.
- Des Moines Water WorksDes Moines500Kserved
- Cedar Rapids Water DepartmentCedar Rapids135Kserved
- Iowa American Water — DavenportDavenport130Kserved
Where the contamination comes from.
Every state has a different industrial fingerprint. The industries below are the dominant historical and active contamination sources in Iowa's drinking water systems.
Iowa's corn-soy agriculture is the dominant U.S. nitrate-exposure driver. Manure-spread operations (dairy and hog confinement) drive bacterial and nitrate contamination in NE Iowa karst zones. Limited heavy industry compared to neighboring states.
What state data flags most consistently.
Drawn from EPA SDWIS sampling records, EWG state summaries, and regional regulatory action over the past five years. Read the full deep dive on each.
Nitrate
Fertilizer and animal waste runoff. Acutely dangerous for infants under 6 months.
Trihalomethanes (TTHMs)
Byproducts of chlorinating water. Linked to bladder cancer at chronic exposure.
Arsenic
A naturally occurring carcinogen. Highest in private wells and the rural Southwest.
Risk isn't evenly distributed.
Infants on formula prepared with nitrate-contaminated well water face the highest acute risk (methemoglobinemia). Pregnant women face thyroid-disruption concerns.
~12% on private wells. Northeast Iowa karst region has the most-documented nitrate and bacterial risk.
What's coming for Iowa's water.
Intensifying spring rainfall events overwhelm nitrate-removal treatment capacity (Des Moines documented). More-frequent extreme weather destabilizes well-water quality on private wells. Karst regions face increasing bacterial contamination risk.
Voluntary statewide
Iowa DNR provides voluntary screening. Several urban districts have voluntarily tested.
Five questions for your next Consumer Confidence Report.
Your utility is required to send you a Consumer Confidence Report annually. Most are dense and procedural. These are the questions worth following up on for Iowa specifically.
- 1
What is my system's nitrate running annual average?
- 2
Does my utility have nitrate-removal treatment capacity, and what is its threshold trigger?
- 3
If I'm in NE Iowa karst country, when was my private well last tested for bacteria?
Most state regulators allow public records requests for the underlying lab reports behind your CCR — your utility should be able to provide them on request.
For nitrate, NSF/ANSI 58 reverse osmosis or ion exchange. Standard carbon filters do NOT remove nitrate.
We don't recommend brands — the NSF/ANSI certification number matters more than the name on the box.
This is the state. Your address is the answer.
State-level patterns don't tell you about your specific tap. Run your ZIP for the live EWG contaminant report on your utility — or build a personalized Water File for your household.
Source-water mix, utility counts, lead-service-line estimates, and private-well shares are approximate, drawn from EPA SDWIS public data and state primacy-agency summaries. Contaminant rankings reflect EWG state-level monitoring data and regional regulatory action — they are not exhaustive. Timeline events are publicly documented. See methodology for the full sourcing. Search EPA SDWIS for Iowa