Arsenic in Drinking Water in Iowa
What residents of Iowa need to know about arsenic in drinking water — including natural geological sources, private well risk, which utilities have documented violations, and how to remove arsenic from tap water.
Source: EPA SDWIS, Iowa Department of Natural Resources, USGS · Last reviewed: 2025-01-01
Quick Answer
Is arsenic in drinking water a concern in Iowa?
Yes. Iowa has documented arsenic in private well water from glacial aquifer geology and from the Cambrian-Ordovician aquifer system in eastern Iowa. Iowa's private wells — used by approximately 300,000 households — face arsenic risk from naturally occurring sources, and the state has one of the more active private well testing programs in the Midwest through the Iowa Well Private Water Supply Program.
Where does arsenic come from in Iowa's water?
Glacial drift aquifers in northern and western Iowa and the deep Cambrian-Ordovician sandstone aquifer in eastern Iowa are the primary arsenic pathways. Arsenic mobilizes from mineral sediments under reducing geochemical conditions common in Iowa's thick glacial deposits. The Dakota aquifer in northwest Iowa also has documented arsenic occurrence.
What should Iowa residents know?
Iowa DNR actively promotes private well testing for arsenic through its Well Water Testing Program. Counties in northern, northwestern, and eastern Iowa with glacial or deep sandstone aquifer dependencies have the highest documented occurrence rates. Iowa's large agricultural private well population should prioritize testing, as arsenic testing is not required and many wells have never been tested.
Key Facts
| EPA MCL | 10 µg/L (10 ppb) |
| MCLG | Zero |
| Primary source | Glacial drift aquifers (northern/northwestern Iowa); Cambrian-Ordovician sandstone (eastern Iowa); Dakota aquifer (NW Iowa) |
| State program | Iowa Well Private Water Supply Program — proactive private well testing with low-income subsidies |
| State regulator | Iowa Department of Natural Resources |
| Health effects | Bladder, lung, skin cancer; cardiovascular; diabetes |
| Effective treatment | Reverse osmosis (NSF/ANSI 58) or activated alumina |
Why Arsenic Matters in Iowa
Iowa has been proactive in private well testing compared to many Midwest states. The Iowa Well Private Water Supply Program has documented arsenic occurrence across multiple counties, particularly in glacial aquifer areas of northern and northwestern Iowa and in deep sandstone aquifer areas of eastern Iowa. Iowa's dense agricultural private well population — on hog, cattle, and row crop operations as well as rural residences — means a substantial number of people may be exposed without knowing it. Iowa DNR provides subsidized testing for low-income well owners.
Iowa Arsenic Program
Iowa DNR monitors arsenic under federal SDWIS. Iowa's glacial aquifer system has documented arsenic in some areas, and the state has an active small system compliance program. Private well owners — particularly in the Des Moines Lobe glacial area — should test for arsenic. Iowa's agricultural use of groundwater means well contamination can also result from legacy pesticide and herbicide applications.
Iowa Utilities With Arsenic Violation Records
The utilities listed below have at least one arsenic violation on record in EPA's SDWIS database. Violations may be open or resolved — see individual utility pages for current status and risk level.
How Does Arsenic Get Into Drinking Water?
Arsenic in drinking water is almost always naturally occurring — it leaches from arsenic-bearing rocks and minerals into groundwater over time. New England granite, Southwest volcanic geology, and Upper Midwest glacial aquifers are the primary high-risk formations. It has no taste, odor, or color.
Full arsenic overview — geology maps, health effects, all 50 statesWho Should Pay Closest Attention
Private well owners in northern Iowa (Kossuth, Palo Alto, Emmet, Pocahontas, Calhoun counties), northwestern Iowa (Sioux, Plymouth, Cherokee, Ida, Monona counties), and eastern Iowa along the Mississippi corridor in counties drawing from deep sandstone aquifers face the highest arsenic risk.
Private well owners near mining districts or agricultural areas
Residents in states with documented volcanic or geothermal geology
Long-term consumers of water from small groundwater systems
Households in homes built before 1960 with older well casings
Residents whose well water has never been tested for arsenic
Anyone living in a state where bedrock wells are common
How to Check Your Situation in Iowa
- 1
Identify your water source. If you use a public utility, use the ZIP lookup on this page to find your system and check its compliance record.
- 2
If on public water, review your utility's most recent Consumer Confidence Report (CCR) for arsenic monitoring data. The MCL is 10 ppb — your report should show recent test results.
- 3
If on a private well, order an arsenic test from a Iowa Department of Natural Resources-certified laboratory. A basic arsenic test costs $15–$40. The state agency website maintains a certified lab list.
- 4
Test your well at the tap — not just at the wellhead. The entire water distribution system within your home can affect water quality.
- 5
If your test shows arsenic above 5 ppb, install certified treatment immediately. If above 10 ppb, do not use the water for drinking or cooking until treatment is installed.
- 6
Retest after installing treatment to confirm it is working as certified. Replace filter media on the manufacturer's schedule — an exhausted filter may not perform as rated.
Treatment Options for Arsenic
Boiling does not remove arsenic — it concentrates it. Standard activated carbon filters (Brita, etc.) do not effectively remove arsenic. Certified treatment is required.
NSF/ANSI Standard 58 — Reverse Osmosis
RO systems certified to NSF/ANSI 58 remove 85–95% of arsenic. Under-sink installation. Most effective for removing multiple contaminants simultaneously. Replace membranes and pre-filters on schedule.
Activated Alumina Filters
Activated alumina is specifically designed for arsenic and fluoride removal. Point-of-use or whole-house options available. Must be certified by NSF International or WQA for arsenic reduction. Requires periodic media regeneration or replacement.
Iron/Manganese Oxidation Filters
Effective for arsenic in iron-rich well water, which is common in the Midwest and New England. Oxidation converts dissolved iron and arsenic to a form that can be filtered out. Best when arsenic is co-occurring with high iron levels.
What does NOT work for arsenic
Standard activated carbon filters (Brita, refrigerator filters, most pitcher filters) do NOT effectively remove arsenic. Boiling concentrates arsenic. Water softeners do not remove arsenic. Only use products with NSF certification specifically for arsenic reduction.
Take Action Now
If you use a private well in Iowa, test for arsenic — especially if you are in a region with granite, volcanic, or sedimentary geology. A basic arsenic test costs $15–$40 at a state-certified lab.
Public water users: check your utility's Consumer Confidence Report (CCR) for arsenic results. The EPA MCL is 10 ppb — any detection warrants attention.
If arsenic is detected above 10 ppb (or even below it, given MCLG is zero), install an NSF/ANSI 58-certified reverse osmosis system for drinking and cooking water.
Standard carbon filters do NOT remove arsenic — do not rely on a Brita or refrigerator filter for arsenic protection.
Frequently Asked Questions
Related Pages
Arsenic — National Overview
All U.S. utilities with arsenic records
Iowa State Overview
All utilities and water quality data
Iowa Well Water Guide
Testing, risks & certified labs for private wells
Reverse Osmosis Guide
Removes 85–95% of arsenic
Best Arsenic Filter Guide
What actually works (carbon doesn't)
PFAS in Drinking Water
The 'forever chemical' contamination overview
All Contaminants
Complete reference library
Data Sources & Provenance
All data on this page is sourced from official U.S. government or public datasets.
Find Your Utility
State Regulator
Iowa Department of Natural Resources ↗