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Along with impurities like lead and pesticides, arsenic is one of the most dangerous water contaminants.
The EPA has set the Maximum Contaminant Level Goal (MCLG – a non-enforceable standard), at zero and the Maximum Contaminant Level (an enforceable standard) at 10 ppb or parts per billion.
Inorganic arsenic, the type commonly found in water, is a proven carcinogenic. It can cause skin, lung, and bladder cancer.
It’s also linked with diabetes, cardiovascular disease, and developmental problems in kids.
Arsenic in water mostly comes from natural deposits in the earth. That’s why it is crucial to have your water tested for arsenic if you get it from a well.
Industrial pollution and certain types of fertilizers can also introduce arsenic into groundwater.
If you use city water, arsenic is not a big concern since your utility has to comply with EPA standards. But it’s still a good idea to have your water tested for any traces of the element.
The most common form of arsenic in water is Arsenate (Arsenic V). This is the easiest type of arsenic to remove.
If your water doesn’t contain enough oxygen, it may occur in the more toxic form called Arsenite (Arsenic III).
Arsenic III is hard to remove even with a reverse osmosis filter. The water needs to go through pre-oxidation to oxidize Arsenic III into Arsenic V, which is easier to remove.
Note that you cannot smell or taste arsenic in water. It also doesn’t have any particular color, nor does it leave stains on surfaces.
The only way to know if your water is contaminated with arsenic is to have it tested at a certified laboratory.
If the lab finds arsenic, you have several affordable water treatment options you can use.
For hard to remove impurities like arsenic and lead, reverse osmosis is the best way to get clean and safe water.
Unlike most filtration methods that target only certain impurities, reverse osmosis removes virtually all contaminants, including arsenic, lead, and bacteria.
The best RO systems can remove up to 95% or more of arsenic V in water.
Note that if you have well water, you may need to install a pre-filter for iron, manganese, and sediment. Otherwise, these impurities can quickly clog up the membrane.
Most reverse osmosis systems are designed for under-sink installation. But there are also some whole house and countertop RO filters.
A distiller is technically not a filter. But it’s still one of the most effective ways of removing arsenic, both III and V, from water.
It’s more effective than the average point of use of the RO filter. It can remove up to 99.9% of arsenic.
These types of filters use metal oxides such as iron oxide, titanium oxide, and aluminum oxide (alumina) that adsorb arsenic out of the water.
The media gets exhausted over time and has to be replaced for the filter to maintain its arsenic-removal capability.
If you use well water, it’s important to pre-filter the water to get rid of iron, manganese, and sediment. These can significantly reduce the life and performance of the adsorption media.
Note that most adsorption media filters can remove both Arsenic III and Arsenic V.
An ion exchange arsenic-removal system works the same way as a water softener. A resin bed picks up arsenic ions as water passes through and exchanges them for chloride ions.
Ion exchange only works for Arsenic V. If there’s any Arsenic III in the water, it must first be oxidized to Arsenic V.
Similar to a water softener, the resin gets exhausted over time and must be regularly regenerated.
For an ion exchange system to work well, the water must have low TDS (less than 500 mg/L) as well as low sulfate levels (less than 50 mg/L).
So depending on your water quality, pre-filtration may be necessary.
This method is useful for groundwater that contains both iron and arsenic III. It works in two steps.
First, the iron and arsenic in the water are oxidized into ferric (insoluble) iron and Arsenic V. The chemicals such as chlorine, potassium permanganate or ozone are added to oxidize the two impurities at the same time.
Note: Air oxidation doesn’t work since it only affects iron. Air does not oxidize Arsenic III.
Next, the arsenic – now in the form of arsenic V – adsorbs onto the oxidized iron. Then both are trapped in a filtration media such as green-sand, Birm, or Pyrolox.
In ideal conditions –specifically an iron to the arsenic ratio of at least 20:1 and relatively low pH –oxidation filtration removes 80-90% of arsenic in water.
This is also a two-step process – coagulation then filtration.
A coagulant such as ferric chloride or ferric sulfate is added to the water. Arsenic binds to the coagulant, forming larger solids that are then filtered out using a filtration media or membrane.
A whole house filter is a point-of-entry system meaning it will treat all the water coming into your home.
It’s the best option if you want all points of use – faucets, and showerheads –to produce arsenic-free water.
Here are our top four whole house water filters.
The Express Water 3-stage whole house system is designed specifically to tackle heavy metals including copper, cadmium, chromium and, of course, arsenic.
It also filters out a wide range of other impurities including pesticides, chlorine, sediment, and VOCs.
The first stage is a sediment filter that traps suspended particles like sand and silt. It has a clear housing, which makes it easy to tell when you need new filters.
The second stage is a KDF filter consisting of catalytic carbon and copper & zinc granules. This is where most heavy metals are removed. It filters arsenic, lead, iron, and mercury.
It also captures chloramines, chlorine, hydrogen sulfide, and fungi.
The final stage is a carbon block filter that deals with chlorine, pharmaceuticals, fine sediment, and VOCs.
Installation requires some basic plumbing, but you can do it yourself. The system comes with a standing frame that you can mount or place on the floor.
The 1” outlets and inlets ensure a steady flow rate from faucets and showers.
The filters are good for 100,000 gallons or about 6-12 months, depending on your water quality. Use the included pressure gauges to determine when it’s time to replace a filter.
The 3-stage Big Blue whole house filter uses activated alumina to remove arsenic and fluoride.
Two other filters –a 1st stage sediment filter and a 3rd stage carbon filter – remove suspended particulates, chlorine, and various chemicals.
The filters are large to ensure minimal loss of water pressure.
Installation is a 2-hour DIY project. Most of the parts you need are provided including a mounting bracket and screws, hex nipples and a filter housing wrench.
Filter life is about 6-12 months.
This is the best filter if your well or city water contains high levels of arsenic. It can handle arsenic concentration over 100 ppb.
The AFW Filters AdEdge 20 removes both arsenic III and arsenic V.
It uses an adsorption media called Bayoxide E33, a proprietary form of granular iron oxide. It removes up to 99% of arsenic, reducing levels to below the EPA-recommended minimum.
It also adsorbs other heavy metal ions including copper, nickel, lead, and zinc.
The filter comes with a Fleck 2510SXT control head that automatically controls the backwash and regeneration of the filtration media.
The WECO FerrIX A33E is the best ion exchange filter system we could find for homes.
It uses a type of resin called FerrlX A33E to remove arsenic ions from the water. The resin is infused with iron oxide to increase arsenic removal.
The WECO ion exchange filter comes with a Fleck 5810 XTR2 control head that automatically controls backwashing cycles to clean the resin.
Though pricey, it’s one of the best arsenic filters for city and well water. The stainless steel housing ensures durability.
If you only want to filter arsenic from drinking and cooking water, a point-of-use reverse osmosis system will do. Here are our favorite RO water filters.
If you are using well water, we highly recommend installing a pre-filter for iron, manganese, and sediment to avoid clogging the RO filter.
Remember that RO systems only deal with arsenic V, the most common form found in water. If your water contains arsenic III, reverse osmosis is not the best choice.
The Home Master TMAFC-ERP is of the best and most reliable under-sink RO filters around.
It features multiple filters that remove chlorine, chloramines, sediment, and VOCs. A high-quality RO membrane then filters out heavy metals such as arsenic, lead, copper, and mercury as well as biologicals including bacteria and cysts.
The membrane also removed dissolved minerals, including the healthy ones. But don’t worry that your water will taste flat or be too acidic.
Two remineralization points return some of the good minerals into the water before it comes out of the faucet.
Unlike most RO systems, the Home Master TMAFC-ERP comes with a permeate pump that increases flow rate out of the faucet and reduces the amount of water wasted.
It also features a modular filter design where the housing and cartridge are one. This not only prevents leaks because of worn-out filter housings, but it also makes filter replacement easy and mess-free.
The filters have a lifespan of around 2,000 gallons or about one year. The membrane lasts 3-5 years.
Our second recommendation is also a Home Master. The TMHP HydroPerfection under-sink RO system is particularly ideal for homes that use well water.
It has an iron pre-filter, so you don’t have to worry about pre-treating the water first. It also includes filters for sediment, chlorine, chloramines and various organic chemicals.
This leaves the semi-permeable membrane to deal with the hard-to-filter impurities such as arsenic and lead.
The TMHP HydroPerfection has the same modular filters as the TMAFC-ERP. Filter capacity is also similar – 2,000 gallons or about one year (3-5 years for the membrane).
It also comes with an integrated permeate pump that increases water pressure and reduces wastage.
For city water users who want to remove arsenic and other impurities, we recommend the Home Master TMAFC-ERP.
For well water users who want to remove arsenic, iron and other contaminants common in groundwater, the Home Master TMHP HydroPerfection is the best choice.
If you cannot or don’t want to install an under-sink reverse osmosis filter, the APEC RO-CTOP-C is a good alternative.
The compact filter sits on your countertop and connects directly to your water faucet.
It’s small enough that you can even carry it with you and use it in hotel rooms or a friend’s place. It’s also perfect for cabin getaways, dorm rooms, apartments, RVs and boats.
The RO-CTOP-C features a 4-stage filtration system that removes chlorine, sediment, organic chemicals, microbes, arsenic, and a variety of heavy metals.
The only sacrifice you’ll make is water flow. Purified water comes out in a slow trickle. But you can solve this problem by storing drinking water in a large bottle or pitcher for easy access.
Most faucet water filters, including PUR and Brita, do not remove arsenic. They focus mostly on chlorine and other chemical impurities.
But you can find several faucet water filters that claim to remove arsenic. Most don’t specify what percentage they filter out and lack any certifications.
Here are three we found on Amazon. They include countertop and faucet-mounted filters.
We recommend them for city water with low levels of arsenic. If you are using well water, you are better off with an RO or whole house system that you are sure removes at least 90% of arsenic.
This one sits on the countertop and connects to the faucet via an adapter. The multi-stage filtration cartridge removes chlorine, heavy metals like arsenic and lead, VOCs and sediment. The filter is available in 7 colors.
This one’s also a countertop filter that comes with its faucet to dispense filtered water. It uses a multi-stage PH007 filter cartridge that removes chlorine, arsenic, lead, fluoride, and scale.
This is a faucet-mounted water filter. It’s fitted with an 8-stage PH006 filter cartridge that removes chlorine, chloramine, heavy metals like arsenic and some fluoride. It also balances the water’s pH to reduce acidity.
A water filter pitcher is the easiest way to go if you want to remove arsenic and a host of other impurities from your drinking water.
It requires no installation and doesn’t interfere with your faucets or plumbing.
Water filter pitchers from Brita and PUR don’t remove arsenic.
The Brita Longlast Filter that we normally recommend for Brita pitchers and faucet filters is only good for lead and a dozen other impurities including chlorine, mercury, and benzene.
But other good quality water filter pitchers remove most of the arsenic from drinking water.
Berkey pitchers use gravity-fed filters that provide better filtration than pitchers that use pressure-fed filters. Make sure the pitcher uses a PF-2 filter, which removes 99.9% of Arsenic III and V. It’s also the best filter for fluoride removal.
The Aquagear pitcher removes 99.8% of arsenic as well as chlorine, lead, and fluoride.
The Seychelle water filter pitcher is best known for its ability to increase water alkalinity to as high as 9.5. But it also filters out arsenic (99.9% as per the manufacturer’s claims) and various other impurities including chlorine, VOCs and heavy metals.
Some types of activated carbon can remove some of the arsenic in water. The removal rate is 30% to 70% depending on the type and micron rating of the carbon filter.
In most cases, this is not enough to offer complete protection from arsenic (remember the EPA recommends zero levels of arsenic).
That’s why carbon filtration is often not used for arsenic removal on its own. If a carbon filter is used to remove arsenic, it’s usually in conjunction with another filter such as iron oxide.
No, a water softener has no effect on arsenic or any heavy metals for that matter. But it can be used to pre-treat the water (remove iron and hardness minerals) before the water goes through an arsenic filter.
Most of the arsenic comes from the earth. It occurs naturally in the soil and rocks and can contaminate groundwater. That’s why well water is more likely to have arsenic compared to municipal water.
Other possible sources include industrial pollution, paints, dyes, soaps and certain fertilizers.
Arsenic is one of the most dangerous water contaminants, leading the EPA to set a Maximum Contaminant Level Goal of zero.
It is associated with cancer, developmental problems, skin problems, heart disease, and diabetes. Long-term exposure is dangerous for both adults and kids.
Distillation and reverse osmosis are two of the best ways to remove most of the arsenic from water. These methods can remove over 99% of arsenic, though reverse osmosis only removes arsenic V.
Other effective methods include ion exchange, adsorption, oxidation-filtration, and coagulation-filtration.
Some of these methods, such as coagulation are used on an industrial scale while others like adsorption, are great for residential arsenic-removal filters.
No. If anything, it does the opposite. As the water evaporates, the concentration of arsenic slightly increases.
If you want a quick short term method of removing arsenic before you buy an under-sink or whole house filter, drink bottled water.
Alternatively, use a water filter pitcher or install a faucet water filter.
Since you cannot smell, taste or see arsenic in water, the only way to be sure it’s there (or not there) is by testing.
The easiest way is using an arsenic testing kit. It’s not just helpful when you are deciding whether to buy an arsenic filter; it’s also handy for checking whether your arsenic filter is making a difference.
For the first time testing, however, we highly recommend taking a water sample to the lab. It’s cheap and in some places, free.
Ed is a water specialist in Tampa, FL. He built CleanerSofterWater.com to help his friends and family learn about DIY solutions to common water quality issues in the home.
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