We’ve extensively researched and compared the top arsenic removal filters available today and compiled a list of the most effective systems. We ranked the following products based on their ability to remove arsenic from water, their quality of build, filter lifespan, and customer satisfaction.
US Water Systems Defender Whole House RO System
Crystal Quest Arsenic Whole House Water Filter
Waterdrop G3P800
📌 Things You Need to Know
- You’re probably struggling to find a good arsenic removal system because arsenic is typically not removed by common filtration processes like activated carbon adsorption.
- Other buyer’s guides might point you towards products that remove small amounts of arsenic, but not enough to be worthy of your money.
- We’ve focused on the tap water filters that remove more arsenic than any other water filters available today. We know that you’re looking for the best arsenic removal system, so you expect at least 95%+ arsenic reduction.
- When choosing between water filters for arsenic removal, consider your budget, your water quality, your preferred installation and maintenance, and more.
Table of Contents
- 🥇 Best Arsenic Removal Systems
- 📊 Comparison Chart of Arsenic Removal Systems
- ⭐ Reviews – Best Water Filter for Arsenic
- 🧾 Arsenic Water Filter Buyer’s Guide
- 🤔 What is Arsenic?
- ❔ How Does Arsenic Get Into Water?
- ☠️ What Are the Risks of Arsenic in Drinking Water?
- 🧪 How to Test For Arsenic in Water
- 🚰 Water Treatment Methods For Arsenic Removal
- 📋 Considerations When Looking For an Arsenic Removal System
- 🙋 Frequently Asked Questions
🥇 Best Arsenic Removal Systems
- Best Overall Protection US Water Systems Defender Whole House RO System
- Top Non-RO Whole House System: Crystal Quest Arsenic Whole House Water Filter
- Best Point of Use System: Waterdrop G3P800
- Best Non-RO POU Filter: Clearly Filtered Under Sink Filtration System
- Great for Renters: AquaTru
- Best Pitcher:
Clearly Filtered Water Pitcher
📊 Comparison Chart of Arsenic Removal Systems
| System | US Water Systems Defender | Crystal Quest Arsenic Filter System | Waterdrop G3P800 | Clearly Filtered Under Sink Filtration System | AquaTru | Clearly Filtered Water Pitcher |
|---|---|---|---|---|---|---|
| Ranking | 1st | 2nd | 3rd | 4th | 5th | 6th |
| Ratings | 5/5 | 5/5 | 5/5 | 4.5/5 | 4.5/5 | 4.5/5 |
| Price | $8,595+ | $2,389+ | $999.00 | $550.00 | $449.00+ | $90.00+ |
| As Reduction Rate | 99% | 99% | 99% | 94.3% | >98% | 99.9% |
| Contaminants Reduced | 1,000+ | 10+ | 1,000+ | 232+ | 83+ | 365+ |
| Certifications or Testing | NSF certified components | - | NSF 58, 372 | NSF 42, 53, 401 | NSF 42, 53, 58, 401, P473 | NSF 42, 53, 401 & 473 |
| Process | RO | Adsorption | RO | Carbon + Ion Exchange | Mechanical + RO + Carbon | Carbon + Ion Exchange |
| Filter Life | 2 years (RO), 6 to 12 months (pre-filter) | 750K or 1M gallons | 6, 12, 24 months | 2,000 gallons | 600 – 1,200 gallons | 100 gallons |
| Annual Cost | $200 – $800 | ~$30 | ~$145 | $396-$440 | ~$80 | ~$150 |
| Warranty | Lifetime (Tanks) 2 years (RO System Components) | 1 year | 1 year | Lifetime | 1 year | Lifetime |
⭐ Reviews – Best Water Filter for Arsenic
US Water Systems Defender Whole House RO System
In our opinion, the US Water Systems Defender Whole House Reverse Osmosis System is the best overall water filter to remove arsenic. We love this filter because it uses six thorough stages of filtration – more filter stages than any other product on this list – to remove virtually all arsenic and the majority of other dissolved solids in your entire home’s water supply.
Key Features:
- Arsenic-free whole home water – Using a reverse osmosis system like the Defender means that your whole home’s water supply will benefit from water that’s free of arsenic, lead, PFAS, PFOAs, chlorine, bacteria, sediment, and much more.
- 4 thorough filtration stages – There are 4 comprehensive stages to this system: a pre-filter, a reverse osmosis membrane, optional pH neutralization and remineralization, and UV treatment.
- Reassuring warranty – As you’d expect when you’re spending so much money on a water treatment system, the Defender is backed by a lifetime warranty on tanks and two years on all other parts.
Best For:
Folks with the biggest budgets who want the very best arsenic removal water filtration system that money can buy. For the amount of arsenic it can remove and the quality of purified water it produces, many homeowners see this system as a worthy investment.
| USWS Defender Options | Price (140 Gallons) | Price (250 Gallons) |
|---|---|---|
| 2,000 GPD | $8,595 | $8,895 |
| 4,000 GPD | $9,195 | $9,495 |
| 6,000 GPD | $9,795 | $10,095 |
| 8,000 GPD | $10,395 | $10,695 |
Pros:
- We like that you can choose from a number of options to custom-build the system that’s right for you. Choose between 140 or 250 gallons for the storage tank size, opt in or out of a pre-treatment option, and select your water production rate from 2,000 to 8,000 gallons per day. With these options, you can make sure to pick the right system size and water flow for your family.
- No need to worry about the potential water pressure issues from installing a whole-home RO system. Purified water is held in a storage tank before use, so you’ll always have access to clean water for washing, drinking, showering, and using in your home’s appliances.
- Water waste isn’t a major disadvantage in this system, either. The Defender only wastes 1 gallon of water for every 5 gallons made, which is almost unheard of for reverse osmosis.
| Pretreatment Upgrades | Price | Uses |
|---|---|---|
| Bodyguard Plus | $1,300 | Chemical removal |
| Anti-Scalant Injection | $600 | Scale prevention |
| Bodyguard Plus & Anti-Scalant | $1,900 | Chemical removal and scale prevention |
Cons:
- You need close to $10,000 if you want to buy this water filter system. That makes it inaccessible to most folks.
- You get whole house water treatment, which is great, but it also means that a higher volume of water is wasted compared to under-sink RO.
Crystal Quest Arsenic Whole House Water Filter
If you’re looking to remove arsenic from your entire home’s water supply but you don’t want the expense of water waste, the Crystal Quest Whole House Arsenic Water Filter is our top recommended non-RO whole house system.
This advanced whole home filtration system targets arsenic directly with an iron oxide-based filter media, which reduces up to 99% of total arsenic from water.
Key Features:
- 3-stage filtration removes 99% arsenic – The unit uses three filter stages: a sediment filter (which filters out any larger particles of sand, dirt and silt) an arsenic-reducing mineral tank (which reduces up to 99% total arsenic), and a final solid carbon filter (which removes further contaminants and improves water’s taste).
- Reduces tens of tap water contaminants – This water filter system is first and foremost for arsenic removal. However, it can also remove other contaminants like VOCs, pesticides, insecticides, industrial solvents, chlorine, and some heavy metals.
- Multiple sizes & configurations available – The system comes in two capacities: 1.5 or 2 cubic feet of resin. You can also choose between fiberglass and stainless steel for the outer casing.
| Crystal Quest Arsenic Filter Configurations | Price (Fiberglass Casing) | Price (Stainless Steel Casing) |
|---|---|---|
| 1.5 cubic feet | $2,389 | $3,168 |
| 2.0 cubic feet | $2,862 | $3,569 |
Best For:
Folks who aren’t bothered about removing as much as possible from their whole home tap water and want the main focus to be total arsenic removal.
Pros:
- The Crystal Quest Arsenic Whole House Water Filter is one of the only systems to remove both forms of arsenic that commonly occur in water: arsenite (or arsenic 3), and arsenate (arsenic). This should achieve completely arsenic-free water in your home.
- We love all the optional add-ons, like a water softener if you also want to tackle water hardness, and stainless steel casing to improve the unit’s durability.
- It’s good to see a 1-year limited warranty, and Crystal Quest’s customer support is always top-notch.
Cons:
- Costing around $2,000-$3,000, this Crystal Quest model is about one-third of the cost of our top whole-house RO system, but it’s still expensive.
- Installation is a little tricky, as it is for any whole-home system. The good news is that many customers commented on the helpfulness of the user manual for setup.
Waterdrop G3P800
The Waterdrop G3P800 is our top choice for the best point of use system to filter arsenic from drinking water.
This under-sink system offers all the benefits of a reverse osmosis water filter and has been third-party tested to remove more than 90% of total dissolved solids, including arsenic. Plus, it’s sleeker, slimmer, and smarter than most other under-sink reverse osmosis filters.
Key Features:
- Removes arsenic & other heavy metals – The Waterdrop G3P800 has been third-party tested to reduce up to 90% total dissolved solids (TDS), including arsenic, iron, chromium, nitrates, and other impurities.
- 9 stages of filtration – A traditional RO system has four filter stages: a sediment filter, two carbon filters, and a semi-permeable membrane. The G3P800 goes five steps further with two pp cotton layers, a scale inhibitor layer, two activated carbon block layers, an RO membrane, and a UV sterilizer.
- 800 GPD flow rate – Typical reverse osmosis systems have a flow rate of 80-100 gallons per day (GPD), but the G3P800 delivers around ten times this amount (up to 800 gallons per day).
| Upgrades | Price | Uses |
|---|---|---|
| Remineralization Filter | $29.99 | Adding minerals back to water |
| Refrigerator Connector | $32.99 | Connect RO system to refrigerator water line |
Best For:
Anyone who can afford to invest in a premium under-sink reverse osmosis system with third-party test results to achieve the highest quality arsenic-free drinking water.
Pros:
- The Waterdrop G3P800 outperforms its competitors in most categories. It looks better, saves more space, has smarter features, and filters more than the average under-sink RO system.
- It’s always good to see test results to support a manufacturer’s claims. We appreciate that the G3P800 has been third-party tested for up to 90% TDS removal.
- Good news for people who hate plumbing and DIY: this Waterdrop water filter system is super easy to install thanks to its all-in-one tankless design.
Take a look at the data from our third-party laboratory testing for the Waterdrop G3P800 in the table below.
| Contaminant | Pre-Install | Post-Install | % Reduction |
|---|---|---|---|
| Total Dissolved Solids | 84 PPM | 15 PPM | 82.14% |
| Arsenic | 0.0029 PPM | 0 PPM | 100% |
| Barium | 0.0283 PPM | 0.0033 PPM | 88.34% |
| Calcium | 20.2 PPM | 2.6 PPM | 87.13% |
| Chloride | 2.2 PPM | 0 PPM | 100% |
| Copper | 0.203 PPM | 0 PPM | 100% |
| Fluoride | 0.3 PPM | 0 PPM | 100% |
| Lead | 0.0008 PPM | 0 PPM | 100% |
| Magnesium | 2.13 PPM | 0.27 PPM | 87.32% |
| Manganese | 0.0048 PPM | 0 PPM | 100% |
| Nitrate (as N) | 1.1 PPM | 0.1 PPM | 90.91% |
| Potassium | 2.12 PPM | 0 PPM | 100% |
| Selenium | 0.0015 PPM | 0 PPM | 100% |
| Sodium | 9.33 PPM | 1.65 PPM | 82.32% |
| Strontium | 0.199 PPM | 0.025 PPM | 87.44% |
| Sulfate | 7.8 PPM | 0 PPM | 100% |
Cons:
- The Waterdrop G3P800 only has a 3:1 pure to wastewater ratio, but the non-RO systems on this list waste no water whatsoever.
- Around $1,000 upfront is very expensive for an under-sink RO system. Although we think the price is justified, it’ll be too expensive for some people.
Read the Full Review: Waterdrop G3-P800 RO Review
Clearly Filtered Under Sink Filtration System
We’ve found that the Clearly Filtered Under Sink Filtration System is the best non-RO POU filter. Not only can this three-stage under-sink filter reduce more contaminants than any of its competitors, but it’s also third-party tested to reduce up to 94.3% arsenic with a dedicated filter stage (AND you can view the test results online, as it should be).
Key Features:
- Up to 94.3% arsenic reduction – Clearly Filtered is one of the only manufacturers to give an actual figure for reducing arsenic. Only around 0.5% of arsenic may remain in your water after using this system.
- Reduces more than 200 contaminants – Alongside arsenic, this Clearly Filtered model reduces or reduces more than 232 contaminants, including lead, PFAS, fluoride, chlorine, and pharmaceuticals. Plus, the system is third-party tested to NSF standards 42, 53, 401, and 473.
- Three individual filter stages – There are three filter stages in the Clearly Filtered under-sink water filter: a granulated coconut carbon filter, a “special blend” heavy metals & VOCs filter, and a dedicated arsenic and fluoride filter.
Best For:
Anyone looking for the best non-RO POE method of reducing nearly 95% arsenic from a manufacturer that gives real stats on its filter’s performance.
Pros:
- We love that Clearly Filtered gives actual stats on its under-sink filtration system’s performance. We know its exact arsenic reduction capabilities, while other manufacturers make vague statements like: “reduces up to 99.9% arsenic…” with no supporting evidence.
- Unlike the Waterdrop G3P800, the Clearly Filtered system isn’t a reverse osmosis filter. That means you don’t have the disadvantage of water waste. There’s also no RO membrane to replace, making filter changes quick and simple.
- We’re impressed with the filter lifespans – they last for 2,000 gallons, or approximately 15 months, which is 3-6 months longer than average.
Cons:
- For a non-RO system, the Clearly Filtered Under Sink Filtration System is a pricy option. Cost: $550+.
- Expect roughly a 20% water pressure reduction after installing this under-sink water filter.
Read the full review: Clearly Filtered Under Sink Filter System Review – Updated: 2023
AquaTru
Our top choice for renters who want to remove arsenic is the AquaTru Countertop RO System, which is certified to remove 82 contaminants from water. This system was third-party tested with a water supply containing concentrations of 0.050 mg/L arsenate (a common form of arsenic), and found to reduce an average of 98.0% arsenate – very impressive.
The AquaTru comes in four different models:
- The AquaTru Classic, which is AquaTru’s basic and lowest-cost offering. For most people, the Classic should be ideal.
- The AquaTru Connect, an upgrade of the Classic that has built-in WiFi and connects to an app, so you can check your water usage, filter lifespan, and more from your phone.
- The AquaTru Alkaline Classic, which has all the features of the Classic except that the standard VOC filter is replaced by an Alkaline Mineral Boost VOC filter that remineralizes purified water.
- The AquaTru Alkaline Connect, the most expensive model that combines the remineralization alkaline VOC filter with WiFi compatibility.
| AquaTru Configurations | Inclusions | Price |
|---|---|---|
| Classic | RO + VOC Filter | $449 |
| Connect | Wifi RO + VOC Filter | $499 |
| Alkaline Classic | RO + Alkaline Boost VOC Filter | $469 |
| Alkaline Connect | Wifi RO + Alkaline Boost VOC Filter | $519 |
Key Features:
- Up to 98.0% arsenate removal – The AquaTru Countertop Filter is capable of removing arsenic in a single form: arsenate. The system removes up to 98% of arsenate, or a minimum of 95.8%, according to third-party test results.
- Removes 82 contaminants – The system uses the four filter stages we’d expect to see in any good RO unit: a particulate pre-filter, an activated carbon pre-filter, a semi-permeable membrane, and an activated carbon VOC filter to remove 82 contaminants (according to NSF 42, 53, 58, 401, and P473 Standards).
- 25% water waste – This AquaTru model wastes only around 25% of water in the process, which makes it a lot more efficient than most under-sink RO systems (which waste around 3-4 gallons of water for every 1 gallon produced).
Best For:
Renters or people who want the best certified countertop water filter for arsenic reduction that’s easy and non-permanent to install and performs better than most similar models on the market.
Pros:
- We love the manufacturer’s transparency on the subject of the AquaTru system’s ability to remove arsenic. Not only does the datasheet tell us what type of arsenic the system can remove; it also gives a minimum and average amount from third-party testing.
- Most reverse osmosis systems are under-sink models, but the AquaTru operates without needing to be hooked up to your water supply – you’ll just need to power it with electricity.
- We love how easy it is to use the unit. Just add water to the holding tank and switch it on. It’ll take 15 minutes to filter a full tank of water.
For insights into the performance of the AquaTru Countertop RO System, refer to our third-party laboratory testing data below.
| Contaminant | Pre-Filtration | Post-Filtration | % Reduction |
|---|---|---|---|
| Aluminum | ND | ND | ND |
| Barium | 0.014 PPM | 0 PPM | 100.00% |
| Calcium | 23.9 PPM | 0.7 PPM | 97.07% |
| Chloride | 9.2 PPM | 0 PPM | 100.00% |
| Chloroform | ND | ND | ND |
| Copper | 0.0525 PPM | 0 PPM | 100.00% |
| Fluoride | 1.5 PPM | 0 PPM | 100.00% |
| Lead | 0.0009 PPM | 0 PPM | 100.00% |
| Magnesium | 6.08 PPM | 0.36 PPM | 94.08% |
| Molybdenum | 0.0047 PPM | 0 PPM | 100.00% |
| Nitrate (as N) | 2.1 PPM | 0 PPM | 100.00% |
| Phosphorus | 1.1 PPM | 0 PPM | 100.00% |
| Sodium | 9.91 PPM | 0 PPM | 100.00% |
| Strontium | 0.108 PPM | 0 PPM | 100.00% |
| Sulfate | 7.6 PPM | 0 PPM | 100.00% |
| Total Dissolved Solids | 112 PPM | 12 PPM | 89.29% |
| Total THMs | ND | ND | ND |
| Uranium | 0.0182 PPM | 0 PPM | 100.00% |
| Zinc | 0.559 PPM | 0 PPM | 100.00% |
Cons:
- There are a lot of filter changes for this AquaTru system. You’ll need to replace the pre-filters every 6 months. The semi-permeable membrane should be changed every 2 years, and the carbon filter will need replacing every 1 year.
- Because this unit isn’t hooked up to your water supply, there’s a limit to how much water can be filtered at once – only a gallon at a time
Read the Full Review: AquaTru Countertop RO System Review (Updated: 2023)
Clearly Filtered Water Pitcher
Last but certainly not least, the Clearly Filtered Pitcher takes our top spot as the best water filter pitcher for reducing arsenic. This small, portable gravity filtration pitcher reduces up to 98.3% arsenic in water containing 60 ug/L of the contaminant, alongside another 364+ contaminants, according to third-party test results helpfully shared by the manufacturer.
Key Features:
- Impressive contaminant & arsenic reduction – Using a dual-technology approach, Clearly Filtered’s gravity pitcher reduces more than 365 contaminants, including just over 98% arsenic.
- Reliable activated carbon filtration – The pitcher is fitted with an activated carbon filter, which has a unique structure that prevents water from being able to pass straight through. With more twists and turns on its journey from top to bottom, water has a longer contact time with the media, which allows for more contaminants to be reduced at once.
- Independently tested to NSF Standards – To support the manufacturer’s contaminant reduction claims, the Clearly Filtered pitcher is third-party tested to NSF Standards 42, 53, 401 & 473.
| Bundles | Price |
|---|---|
| Pitcher Only | $90 |
| Pitcher + 3 Pack | $245 |
| Pitcher + 6 Pack | $395 |
Best For:
Folks who prefer the convenience and portability of a water filter pitcher but still expect the high-quality performance and arsenic reduction of a complex, multi-stage whole-home or under-sink system.
Pros:
- We love the design of the Clearly Filtered pitcher, which lets you fill the top chamber with water, then pour water from the spout while water is still filtering through the top reservoir. Not all water filter pitchers let you do this.
- Many customers find the Clearly Filtered pitcher convenient thanks to its small, lightweight, compact design. You can store it away when it’s not in use, take it with you to the office or on vacation, and carry it easily from one room in your home to another.
- It’s good to see that each Clearly Filtered filter lasts for 4 months, which is just above the average lifespan of a gravity filter for a pitcher.
Cons:
- The gravity filter takes between 15 and 20 minutes to filter a full batch of water.
- While the filter in the Clearly Filtered pitcher has a good lifespan for a pitcher filter, it’s shorter than the filter lifespans of all the other filters on this list. That means more maintenance for you.
Read the full review: Clearly Filtered Pitcher Review (Updated: 2023)
🧾 Arsenic Water Filter Buyer’s Guide
Looking for more information about arsenic in drinking water? You’ll find it in this buyer’s guide.
🤔 What is Arsenic?
Arsenic is a contaminant that’s found naturally in the earth’s crust. It’s distributed through water, land, and air, and can be very dangerous to human health.
Types of Arsenic in Water
There are two types of arsenic that are commonly found in water: arsenic 3 and arsenic 5.
Arsenic 3
Arsenic 3, otherwise known as arsenite or arsenic III, is the most toxic form of the two. Reductive well waters are most likely to contain arsenite.
Arsenic 5
Drinking water that contains free available chlorine will typically oxidize arsenic 3 into arsenic 5, or arsenate. You’re most likely to find arsenate in aerated surface waters.
❔ How Does Arsenic Get Into Water?
Arsenic is present in groundwater in a number of countries in North and South America. It can be found in particularly high quantities in Mexico, Chile, and Argentina.
A study found that around 2.1 million people in the US may be impacted by dangerously high levels of arsenic, which have been found in wells across 25 different states.
Because arsenic is widely and naturally present in the ground, it leaches into water that seeps through the earth and into private well systems. When rainwater falls onto a surface that contains arsenic, it will pick up arsenic as a result.
Arsenic is also used industrially. It serves a number of purposes, including processing glass, alloying, and hide tanning.
We can be exposed to water containing arsenic by drinking it, using it in food preparation, and in the irrigation of crops.
☠️ What Are the Risks of Arsenic in Drinking Water?
Immediate Effects
If you drink water with particularly high arsenic levels, your body will react immediately. Vomiting, diarrhea, and abdominal pain are all signs of acute arsenic poisoning. You may also experience muscle cramping and tingling in the extremities.
Long-Term Effects
The long-term effects of drinking arsenic in water are usually noticed in the skin.
Arsenic exposure can cause pigmentation changes, hard patches on the soles of the feet and palms of the hands, and skin lesions. This type of reaction usually occurs after 5 years of continuous exposure, and can be avoided if you act fast.
Skin conditions related to arsenic exposure can be a precursor to skin cancer. Additionally, lung and bladder cancer have been linked to ongoing arsenic exposure.
Drinking water containing arsenic has also been linked to diabetes, cardiovascular disease, developmental delays, and pulmonary disease.
In pregnant women, arsenic consumption in water can result in a higher rate of infant mortality.
A child exposed to arsenic in the womb is more likely to suffer from lung disease, kidney failure, cancer, and heart attacks in early adulthood. Arsenic has also been shown in studies to affect memory, intelligence, and cognitive development.
🧪 How to Test For Arsenic in Water
The quickest and simplest way to test your water for arsenic is to buy an at-home test kit. The included test strip will change color when dipped in water to indicate how much arsenic is detected.
Most tests have a color chart with around 5 different shades, from light to dark. Each shade represents a specific bracket.
For instance, completely white might represent 0 ppm of arsenic in your water, while completely orange might represent more than 0.5 ppm of arsenic. The darkening shades of yellow between these colors represent your water’s arsenic levels in brackets up to 0.5 ppm.
Alternatively, if you’re looking for more accurate results, send a sample of your water to a certified laboratory.
You’ll receive a report that tells you exactly how much arsenic is in your water, in parts per million (ppm) or μg L−1.
The EPA’s goal for arsenic in drinking water is 0 µg/L, so if any test detects arsenic, you should act accordingly.
🚰 Water Treatment Methods For Arsenic Removal
There are plenty of options for removing arsenic from drinking water.
The most effective water treatment methods are combinations of several of the following:
- Activated alumina
- Iron oxide
- Oxidation and filtration
- Coagulation and filtration
- Reverse osmosis
- Anion exchange
- Distillation
Adsorption
In the adsorption process, the media grabs onto arsenic particles, binding to them and preventing them from passing any further through the system.
The two most common types of adsorption media are activated alumina and iron oxide.
Activated Alumina
Activated alumina is suitable for treating water that contains both arsenic 5 and 3. This method has the ability to remove more than 95% arsenic from drinking water.
AA can also reduce fluoride, another difficult-to-remove contaminant that many folks are concerned about.
Because no backwashing is required with AA, it’s easy to handle, and no wastewater is produced.
Iron Oxide
Iron oxide is a granular hydroxide-based media. This media has a large surface area and tiny pores that grab onto arsenic in flowing water.
Like activated alumina, iron oxide doesn’t need to be cleaned by backwashing. This means that the media bed will eventually become exhausted, and needs to be replenished regularly.
Oxidation & Filtration
Oxidation and filtration is a two-step process that oxidizes arsenic, then filters it out of water. This process is ideal for treating well water that contains iron, manganese, and sulfur as well as arsenic.
In the first stage of oxidation, the contaminants are oxidized. This causes arsenic to take on the form of arsenic 5 (or arsenic V).
A number of chemicals may be used for oxidation, including potassium permanganate, ozone, and chlorine. Note that chemicals must be used here; air oxidation doesn’t work for removing arsenic.
Once oxidized, arsenic can be adsorbed by the oxidized iron and trapped in a filter media, such as birm or manganese greensand.
When the filter media becomes saturated with contaminants, the system regenerates, flushing the media and freeing up space to allow the oxidation/filtration process to continue.
If your water has an iron-to-arsenic ratio of 20:1, minimum, and its pH level is relatively low, oxidation/filtration is capable of removing 80%-90% arsenic from your water.
Coagulation & Filtration
Coagulation and filtration is similar to oxidation and filtration. The difference is that this water treatment method uses a coagulant in the first stage, instead of a chemical for oxidation.
Most coagulation water filters use ferric sulfate or chloride to remove arsenic. When arsenic binds to the coagulant, it causes a reaction that forms larger particles.
These particles are removed from water using a filtration media. A filter membrane may also be used to remove arsenic at this stage.
Reverse Osmosis
Reverse osmosis is one of the best methods to remove arsenic from water. RO systems can remove more than 95% of arsenic V.
The majority of water filtration systems can only reduce or remove specific contaminants. Reverse osmosis, however, can remove up to 9.99% of all total dissolved solids (TDS), resulting in pure, clean water.
Well owners will need to install a sediment, iron or manganese filter to protect the reverse osmosis membrane from damage.
There are reverse osmosis filter units for countertop and under-sink use, and whole-home reverse osmosis systems are becoming increasingly popular.
Anion Exchange
Anion exchange, or ion exchange, is an arsenic removal option that uses the same exchange process as a water softener.
During anion exchange, arsenic ions are attracted to a resin bed. When these ions bind to the resin, chloride ions are released, “exchanging” the arsenic for equal parts chloride.
Chloride in drinking water doesn’t pose any health risks, making it an ideal element to add to water in place of arsenic.
*Note that anion exchange is only suitable for removing arsenic 5. If you have arsenic 3, you will first need to first use an oxidizing system to convert it into arsenic 5.
Regular regeneration is required in this system, which will produce some water waste.
Ion exchange systems work best when treating water with a low TDS (less than 500 PPM). Your water’s sulfate levels should also be lower than 50 PPM. You may need to use a water filtration system to improve your water quality before using an anion exchange system.
Distillation
Water distillers remove a broad range of impurities, including heavy metals, fluoride, chemicals, bacteria, and, of course, arsenic.
In the distillation process, water is heated up in a chamber until it reaches boiling point. This causes the water to evaporate and rise up as steam.
The majority of waterborne contaminants have much higher boiling points than water and are unable to evaporate, so they’re left behind in the boiling chamber.
The evaporated water travels down a cooling corridor and condenses into water droplets, ready for drinking.
📋 Considerations When Looking For an Arsenic Removal System
Before you buy a water filtration system to remove arsenic, consider the following:
Type of Arsenic
There are several forms of arsenic in drinking water.
Most high-end water filtration systems, like RO systems, can filter arsenic 5 out of water. But arsenic 3 (or arsenic III) is more difficult to remove
Choose the right filter type for your arsenic removal needs.
POE vs POU
Are you looking to remove arsenic from your whole home, or do you just want drinking water that’s free from arsenic?
Whole house arsenic water filters are more expensive, bigger, and generally require more maintenance. But they don’t only remove arsenic from your drinking water – they eliminate it from your home’s water supply entirely.
Or, you might only want a system that can remove arsenic from the water you drink. In that case, a point-of-use filter, like an under-sink system or a countertop reverse osmosis filter, is ideal.
Other Contaminants Present
The majority of arsenic water filter systems are capable of removing more than just arsenic from your water. Test your water to determine whether you’re dealing with any other contaminants that you might want to remove.
In city water, common contaminants are chlorine, lead, nitrate, sulfate, calcium, magnesium and sodium.
Well water is more likely to contain other contaminants like iron, sulfur, manganese, microbiological contaminants, and heavy metals.
To remove the broadest range of contaminants, distillers or under-sink reverse osmosis are the best choices. If you’re only dealing with one or two common contaminants, it’s cheaper to go with another option.
Check out our Common Drinking Water Contaminants Guide for more information on what your water might contain.
Filter Lifespan & Maintenance
The maintenance required for an arsenic filter depends on the type of filter you choose
The average filter cartridge has a lifespan of around 6 to 12 months. In a multi-stage filtration system, this may mean making multiple filter changes on a yearly basis.
For arsenic water filters with a resin, such as oxidation and ion exchange systems, you’ll need to replenish the resin (usually after 5+ years) when it becomes exhausted.
Resin-based water filters may also need to regenerate. This is an automatic process that wastes a small amount of water.
Flow Rate
If you’re looking at a whole home water filter for arsenic, you need to make sure the system is designed to provide adequate water flow to your home.
Choose the system size that’s best suited to you based on your number of bathrooms.
Budget
The most affordable arsenic filters are point-of-use filters, including under-sink filters, water pitcher filters, and countertop water filters. Point-of-entry, whole-home systems are bigger and more expensive.
You shouldn’t only think about what you can afford to pay up-front. Most water filters need yearly maintenance, including filter changes, at an ongoing cost.
🙋 Frequently Asked Questions
Does boiling water remove arsenic?
No. Boiling water won’t remove arsenic – it’ll actually increase the arsenic concentration in your water. When the water evaporates, you’ll end up with the same amount of arsenic in a smaller batch of water.
Can activated carbon remove arsenic?
Yes, a good activated carbon water filter cartridge can remove between 30 and 70% arsenic. Usually, this type of filter is used within a larger water filtration system to filter arsenic more thoroughly.
Can a water softener remove arsenic?
Can a water softener remove arsenic? No. Water softeners are designed to remove hardness minerals, as well as low levels of iron, from water. While they can improve water quality, they won’t have any effect on your water’s levels of arsenic.
