Arsenic in Drinking Water in Arkansas
What residents of Arkansas 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, Arkansas Department of Health, USGS · Last reviewed: 2025-01-01
Quick Answer
Is arsenic in drinking water a concern in Arkansas?
Arsenic is a moderate concern in Arkansas, particularly in the Ouachita Mountains and Ozark Plateau regions where arsenic-bearing rocks contribute to elevated groundwater concentrations. The Arkansas River Valley and areas with sulfide mineral deposits in the Ouachita Mountains can have elevated naturally occurring arsenic in groundwater.
Where does arsenic come from in Arkansas's water?
Naturally occurring arsenic from Ouachita Mountain sulfide deposits and Ozark Plateau carbonate formations is the primary pathway. Small groundwater systems and private wells in these regions face the highest risk. Arsenic in mining-affected areas of the Ouachita Mountains — where historical gold and silver prospects occurred — can be elevated above background levels.
What should Arkansas residents know?
Private well owners and small water systems in Polk, Montgomery, Scott, and Yell counties in the Ouachita Mountain region, and in the Ozark counties of Benton, Carroll, and Madison, should test for arsenic. Arkansas DOH monitors public water systems but private well owners have no regulatory protection.
Key Facts
| EPA MCL | 10 µg/L (10 ppb) |
| MCLG | Zero |
| Primary source | Sulfide mineral deposits in Ouachita Mountains; carbonate geology in Ozark Plateau |
| State regulator | Arkansas Department of Health — Engineering Section |
| Private well risk | Ouachita Mountain and Ozark Plateau counties — test independently |
| Health effects | Bladder, lung, skin cancer; cardiovascular; diabetes |
| Effective treatment | Reverse osmosis (NSF/ANSI 58) or activated alumina |
Why Arsenic Matters in Arkansas
Arkansas has localized arsenic concerns in its mountainous western and northwestern regions, where geology creates conditions for arsenic occurrence in groundwater. The Ouachita Mountains contain sulfide mineral deposits that contribute arsenic naturally. Arkansas's significant rural private well population in these areas faces unregulated exposure. The state's generally good surface water quality in the Mississippi Alluvial Plain region means public systems drawing from the Arkansas and White rivers tend to have lower arsenic levels.
Arkansas Arsenic Program
Arkansas DH monitors arsenic under the federal SDWIS framework. Arsenic is a secondary concern in Arkansas compared to other states, though some groundwater in the Mississippi Alluvial Plain aquifer in eastern Arkansas has documented arsenic. Private well owners in alluvial areas of eastern Arkansas should test for arsenic.
Largest Arkansas Water Utilities
No arsenic violations on record in EPA SDWIS for Arkansas utilities in our database. Browse the largest utilities to review their full water quality record.
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 and small system users in the Ouachita Mountain counties (Polk, Montgomery, Scott, Yell, Pike) and Ozark Plateau counties (Benton, Carroll, Madison, Newton) in western and northwestern Arkansas 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 Arkansas
- 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 Arkansas Department of Health-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 Arkansas, 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
Arkansas State Overview
All utilities and water quality data
Arkansas 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.
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Arkansas Department of Health ↗