Quick answer: The most reliable ways to remove arsenic from drinking water are reverse osmosis and specialty adsorptive filters, such as iron-based or activated alumina media. Both work best on arsenic 5. Arsenic 3 usually needs to be oxidized first, for example with chlorine or an oxidizing filter. Test your water first so you know how much is present and which form.
Arsenic is one of the most common natural contaminants in well water, and it has no taste, color or smell. Long-term exposure raises health risks, so it’s important to know whether your water has it and how to remove it. While municipal systems are regulated, private wells are not, so testing and treatment are up to the homeowner.
Understanding Arsenic and Groundwater ContaminationArsenic is a naturally occurring metalloid that primarily enters groundwater through mineral deposits. Secondary sources include industrial activity and agricultural runoff. These types of groundwater contamination are a leading cause of arsenic in well water.
Because groundwater moves slowly, contaminants persist, so regular testing matters. The right treatment depends on your water chemistry, the arsenic level and which form of arsenic is present.
Well Water vs Municipal Water: Risk ComparisonMunicipal systems must meet EPA safe drinking water standards, but private wells rely on homeowner oversight.
- Municipal water: Must meet the EPA’s enforceable maximum contaminant level (MCL) of 10 ppb arsenic
- Well water: Not regulated; higher risk of arsenic in well water
- Monitoring: City water is routinely tested; well water is not
- Responsibility: Homeowners must manage water testing for arsenic and treatment
Learn more: Is tap water safe to drink?
Regulatory Limits and Public Health Guidelines
The EPA sets the maximum contaminant level for arsenic in drinking water at 10 parts per billion (ppb). While this supports drinking water safety, research continues to evaluate arsenic health risks at lower levels. This makes water testing for arsenic essential, even when levels appear compliant.
Testing Your Water for Arsenic: At-Home vs Laboratory
Water testing for arsenic can be done using home water testing kits or professional lab analysis. Reliable home water testing kits are a practical first step for homeowners. Home water testing kits offer quick screening but cannot distinguish between arsenic III and arsenic V, which impacts arsenic removal techniques.
- Collect a water sample
- Add testing reagents per kit instructions
- Wait for the reaction to develop
- Compare results to a reference chart
Testing for arsenic with a home test kit is important. If arsenic is present in your home test kit, find a certified drinking water lab that can determine the concentration of arsenic III and arsenic V, as effective treatment choices depend on this information.
Learn more: How to test water at home with a water test kit
Health Risks of Arsenic Exposure
Arsenic health risks are associated with long-term exposure, even at low concentrations. Understanding arsenic exposure symptoms is key when evaluating drinking water safety.
Common arsenic exposure symptoms include:
- Nausea and vomiting
- Digestive issues
- Numbness in extremities
- Skin irritation
- Increased risk of cancer and diabetes
Long-term exposure to arsenic in drinking water is linked to skin, bladder and lung cancer, according to the EPA. These risks are why testing and proper treatment matter.
There are several arsenic removal techniques available, and choosing the right method depends on water chemistry and arsenic type. Removing arsenic from water effectively often involves a combination of treatment technologies and appropriate filtration systems. Many of these methods require pretreatment to oxidize arsenic from As3 to As5. Oxidation can be accomplished with chlorine or an oxidizing filter.
Reverse Osmosis Systems
Reverse osmosis is one of the most widely used arsenic removal techniques and is highly effective at removing arsenic V (As5). Reverse osmosis is a leading solution for removing arsenic from water in residential applications, with many homeowners choosing dedicated reverse osmosis systems. Look for a system certified to NSF/ANSI 58 for arsenic reduction. However, arsenic III (As3) requires pretreatment to convert it into As5 for optimal removal efficiency.
Reverse osmosis systems are available as point-of-use systems for drinking water or whole-house systems for comprehensive filtration systems.
- Highly effective at removing arsenic V (As5)
- Requires pretreatment for arsenic III (As3)
- Available as point-of-use and whole-house filtration systems
Learn more: What is a Reverse Osmosis System and How Does It Work? | 5 of the Best Reverse Osmosis Systems
Adsorptive Media Filters
Adsorptive media, such as iron-based (ferric oxide) media and activated alumina, grab arsenic as water flows through a tank or cartridge. They’re a popular whole-house option because they don’t create wastewater. Like RO, they work best on arsenic V, so arsenic III should be oxidized first. The media is replaced when it’s used up, and pH, phosphate and silica in your water can shorten its life.
- Good whole-house option with no wastewater
- Works best on arsenic V
- Media must be replaced periodically
Learn more: Shop filter media
Ion Exchange Systems
Ion exchange systems use anion exchange resin to remove arsenic by exchanging arsenic ions with harmless ions. These systems are effective for arsenic V but less effective for arsenic III without pretreatment.
Ion exchange systems may have limitations in high pH water and water with sulfates. Either issue can significantly reduce arsenic removal efficiency.
- Uses anion resin to remove arsenic V (As5)
- Less effective for arsenic III (As3) without pretreatment
- Performance may decline in high pH water
Distillation
Distillation is another method for removing arsenic from water by separating contaminants through evaporation. In some treatment setups, pre-filtration such as activated carbon may be used alongside distillation to improve overall water quality—learn more about activated carbon filters. Distillation is technically effective but not always practical for homes.
- Effective for heavy metal contamination
- Produces high-purity water
- Limited by slow production and energy use
Learn more: What is a Water Distiller and How Does it Work? | Is Distilled Water Safe to Drink?
What Does Arsenic Removal Cost?Arsenic removal cost varies depending on testing and filtration systems.
- Home water testing kits: $20–$150 (2026 prices)
- Under-sink reverse osmosis systems: $150–$600 (2026 prices)
- Whole-house filtration systems: $1,000–$5,000+ (2026 prices)
- Professional lab testing: $50–$300 (2026 prices)
Does boiling water remove arsenic? No—boiling water does not remove arsenic and may increase concentration.
Bottled water may still contain arsenic depending on the source, so removing arsenic from water at home is often more reliable.
Frequently Asked QuestionsWhat are the symptoms of high arsenic in water?
Common arsenic exposure symptoms include nausea, digestive issues, and long-term health risks.
Will a Brita filter remove arsenic?
Most standard filters do not effectively remove arsenic.
How effective are home filtration systems for arsenic?
Reverse osmosis is one of the most effective arsenic removal techniques.
How often should well water be tested?
Water testing for arsenic should be done at least annually.
What is the EPA limit for arsenic in drinking water?
The EPA sets an enforceable maximum contaminant level (MCL) of 10 ppb for arsenic in public drinking water. Private wells aren't regulated, so well owners should test regularly and treat water above that level.
Will my refrigerator filter remove arsenic?
Probably not. Most refrigerator filters are carbon filters certified for chlorine taste and odor, and sometimes lead, but not arsenic. Check the filter's performance data sheet; if arsenic isn't listed, assume it isn't removed. For arsenic, use a reverse osmosis system or a dedicated arsenic filter.
Protecting Your Water Supply Long-TermTo maintain drinking water safety, test regularly, understand contamination levels, and implement the right filtration systems. Arsenic treatment is an ongoing process, especially for well water: keep up with filter changes and retest after installing a system to make sure it’s working.
If you have any further questions about which filtration method is right for you, please don’t hesitate to contact our experts.
