Arsenic in Drinking Water in Mississippi
What residents of Mississippi 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, Mississippi Department of Health, USGS · Last reviewed: 2025-01-01
Quick Answer
Is arsenic in drinking water a concern in Mississippi?
Arsenic is a moderate concern in Mississippi, primarily from naturally occurring sources in the alluvial aquifer systems of the Mississippi Delta and Gulf Coastal Plain sedimentary aquifers. Reducing geochemical conditions in Louisiana and Mississippi's shared alluvial geology can mobilize arsenic from sediments. The Mississippi Delta region — Mississippi's most important agricultural area and a historically underserved community — faces some of the highest groundwater arsenic exposure risk in the state.
Where does arsenic come from in Mississippi's water?
Naturally occurring arsenic in the Mississippi River Alluvial Aquifer (which underlies the Delta) and Gulf Coastal Plain sedimentary aquifers is the primary pathway. Reducing geochemical conditions in the organic-rich alluvial sediments of the Delta mobilize arsenic from iron oxide minerals. Deep confined aquifer systems in southern Mississippi may also have elevated arsenic under reducing conditions.
What should Mississippi residents know?
Mississippi Delta private well owners and small water systems in the alluvial lowlands face the most direct arsenic risk. Mississippi DOH monitors public water systems, but the Delta's many small, resource-limited water systems may have challenges implementing arsenic treatment under the MCL. Private well owners — particularly in rural Delta counties — have no regulatory protection.
Key Facts
| EPA MCL | 10 µg/L (10 ppb) |
| MCLG | Zero |
| Primary source | Mississippi River Alluvial Aquifer (Delta region); Gulf Coastal Plain confined aquifers (southern MS) |
| Environmental justice concern | Delta region communities face multiple health disparities — arsenic adds water quality dimension |
| State regulator | Mississippi Department of Health |
| Health effects | Bladder, lung, skin cancer; cardiovascular; diabetes |
| Effective treatment | Reverse osmosis (NSF/ANSI 58) or activated alumina |
Why Arsenic Matters in Mississippi
The Mississippi Delta — home to significant African American farming and rural communities — faces arsenic exposure from alluvial groundwater that may be underdiagnosed due to limited testing resources. The region already faces multiple public health disparities, and arsenic adds a water quality dimension. Mississippi's many small community water systems — some of the smallest and most resource-constrained in the country — face real challenges in testing, treating, and reporting arsenic compliance. Mississippi DOH has provided technical assistance but resources are limited.
Mississippi Arsenic Program
Mississippi DH monitors arsenic under federal SDWIS. Mississippi's Coastal Plain geology generally produces low natural arsenic in groundwater. Arsenic is not a primary concern for most Mississippi residents, though private well owners should include it in a comprehensive baseline test.
Largest Mississippi Water Utilities
No arsenic violations on record in EPA SDWIS for Mississippi 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
Mississippi Delta county residents in Bolivar, Sunflower, Humphreys, Washington, Issaquena, Sharkey, and Warren counties drawing from alluvial aquifers face the highest arsenic risk. Gulf Coastal Plain counties in southern Mississippi with deep confined aquifer users also face some 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 Mississippi
- 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 Mississippi 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 Mississippi, 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
Mississippi State Overview
All utilities and water quality data
Mississippi 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
Mississippi Department of Health ↗