Well Water Filter

Looked around for a well water filter to eliminate low levels of arsenic with no luck, anyone here have any ideas to filter this?

I read in another thread that person was using a reverse osmosis in his home and was looking for suggestions for watering plants.

Since this is in home care I assume you want something for inside the home.

Have you look in the reverse osmosis filter system?  That is what we use since our water is alkaline.

It looks like a reverse osmosis system or one of the commercial absorption systems are what are readily available.

I did find a link to some research using an absorption layer in a sand filter that looked interesting. I only skimmed the beginning though. https://iwaponline.com/washdev/article/15/8/652/108796/A-review-on-the-application-of-bio-sand-filters

Found this on Tapwater.org
Arsenic
A naturally occurring element found in rock and soil that can dissolve into groundwater.
WHERE DOES IT COME FROM?

Natural geological deposits, mining operations, and agricultural runoff.
HEALTH RISK

According to the EPA and WHO, long-term exposure is linked to skin, bladder, and lung cancer, as well as cardiovascular disease.
HOW TO REMOVE IT

Reverse osmosis is the most effective home treatment for arsenic. Some activated alumina filters also work.
Arsenic is a naturally occurring element found in rock, soil, and groundwater throughout the world. It is one of the most significant drinking water contaminants because of its prevalence and toxicity — the EPA classifies arsenic as a known human carcinogen. Like lead, arsenic in water is completely invisible: it has no taste, no smell, and no color, even at dangerous concentrations.

The EPA's Maximum Contaminant Level for arsenic is 10 parts per billion (ppb), set in 2001. The MCLG (health goal) is zero, reflecting the fact that any level of arsenic exposure carries some risk.

That 10 ppb limit is a regulatory compromise between health protection and treatment costs — not a safety guarantee. The EPA itself estimates that lifetime exposure to arsenic at 10 ppb could cause up to 600 cancers per million people. California's Public Health Goal for arsenic is 0.004 ppb (4 parts per trillion) — roughly 2,500 times stricter than the federal limit. The gap between what's legal and what's considered truly safe is unusually wide for arsenic.

Why Is Arsenic Dangerous?

Arsenic is a potent carcinogen even at low levels. According to the EPA, WHO, and ATSDR, long-term health effects include:

Skin, bladder, and lung cancer
Cardiovascular disease and heart problems
Type 2 diabetes
Skin changes including darkening and thickening
Nervous system effects including numbness
Developmental effects in children, including reduced IQ
How Does Arsenic Get Into Water?

Arsenic enters water primarily through natural geological processes — it dissolves from rock and soil into groundwater. It is particularly common in the western United States, parts of New England, and areas with volcanic rock. Industrial sources include mining, smelting, and agricultural pesticide runoff. Groundwater sources are far more likely to contain arsenic than surface water (lakes and rivers).

Who Is Most at Risk?

Private well owners. Roughly 23 million US households get their drinking water from private wells, which are not regulated by the EPA. The well owner is solely responsible for testing and treatment. Arsenic in groundwater is especially common in areas with volcanic rock and certain aquifer types — and many well owners have never tested for it.

Western US and New England residents. Arsenic concentrations in groundwater are geologically driven and vary dramatically by region. The most affected areas include Arizona, Nevada, California, Oregon, parts of the Midwest (particularly Iowa and Wisconsin), and portions of New England (Maine, New Hampshire). The reason: bedrock in these regions — volcanic deposits, certain sedimentary formations — contains naturally occurring arsenic that dissolves into groundwater over time.

Children and pregnant women. Children are particularly vulnerable because they consume more water per kilogram of body weight than adults. Pregnant women should minimize exposure, as arsenic crosses the placenta and has been linked to low birth weight and developmental effects. Long-term exposure at even low levels can cause cumulative damage across all age groups.

How to Test Your Water for Arsenic

Arsenic has no taste, no smell, and no color — even at concentrations far above the EPA limit. A laboratory test is the only way to detect it.

If you're on a public water system: Your utility tests regularly and publishes results in the annual Consumer Confidence Report (CCR). You can look up your city's arsenic data on TapWater.org. If your utility reports arsenic below the EPA limit, that's a good sign — but the system-wide average doesn't tell you exactly what arrives at your specific tap.

If you have a private well: No government agency tests your water for you — it's entirely on you. The recommendation: test at least once for arsenic through an ELAP-certified laboratory. If your well was recently drilled, retest after 6 months, as arsenic levels can fluctuate during the initial period. If the first test shows no arsenic, routine retesting is generally not necessary.

Which tests work: Standard home test strips are not accurate enough for arsenic at the levels that matter. A lab-based test kit using EPA Method 200.8 (ICP-MS) is the standard — it can detect arsenic down to 1 ppb. We've reviewed the best options in our water test kits guide.

How to Remove Arsenic From Your Water

Understanding arsenic III vs. arsenic V: There are two forms of arsenic in water. Arsenate (arsenic V) is relatively easy to filter. Arsenite (arsenic III) is much harder to remove and must first be oxidized to arsenic V — typically using chlorine or hydrogen peroxide — before a filter can be effective. A lab test can determine which form is present, and this directly impacts which treatment system you need.

Effective treatment methods:

Reverse Osmosis (RO): The most effective and practical home treatment, removing 90–95% of arsenic. An under-sink RO system typically costs $150–$500 and protects your drinking water tap.
Activated Alumina: Effective especially for arsenate (arsenic V). Requires periodic media replacement.
Iron-Based Adsorption: Newer technology using iron oxide media, very effective for both forms of arsenic.
Distillation: Effective but slow and energy-intensive — impractical for daily use.
What does NOT work: Standard activated carbon filters — including most Brita pitchers, refrigerator filters, and basic faucet filters — do not remove arsenic. Water softeners do not remove it either. And boiling makes it worse: water evaporates, but arsenic stays behind, increasing the concentration.

Certification matters: Any filter marketed for arsenic removal should be certified to NSF/ANSI Standard 53 (health-related contaminants) or NSF/ANSI Standard 58 (reverse osmosis). You can verify certifications at nsf.org or through the Water Quality Association.

Point-of-use vs. whole-house: An under-sink RO system ($150–$500) protects your drinking water faucet. For whole-house treatment (every tap), arsenic-specific adsorption or oxidation-based systems are available but significantly more expensive ($1,000+) and typically require professional installation.

What to Do If Your Water Has Arsenic

Your response should match the level detected:

Under 10 ppb (within EPA limit): Your water meets the legal standard. Health risks at these levels are low but not zero — the EPA's own health goal is zero. An RO filter at your drinking water tap is a sensible precaution, especially if children or pregnant women are in the household.

Over 10 ppb (exceeds EPA limit): Switch to an alternative drinking water source or install a certified filter immediately. If you're on public water, contact your utility — exceedances must be reported and addressed. If you're on well water, a professional filtration system is strongly recommended.

Over 35 ppb: At these levels, children and infants face elevated short-term risk. Switch to filtered or bottled water immediately, including for preparing baby formula and cooking.

Over 500 ppb: Do not use the water for bathing or showering. Secure an alternative water supply and contact your local health department.

Important: Arsenic is not absorbed through skin in meaningful amounts during normal use. Bathing, showering, laundry, and dishwashing are safe at levels below 500 ppb. The risk is exclusively from ingestion — drinking and cooking.

Arsenic Levels in US Cities

Based on verified municipal water quality reports (Consumer Confidence Reports) from 17 cities.

DETECTED WITHIN LIMITS (17)

Mesa, AZ
8.37 ppb(84% of limit)
Bakersfield, CA
7.27 ppb(73% of limit)
Tucson, AZ
6.64 ppb(66% of limit)
Phoenix, AZ
6 ppb(60% of limit)
Fresno, CA
5.12 ppb(51% of limit)
Omaha, NE
4.9 ppb(49% of limit)
El Paso, TX
4.3 ppb(43% of limit)
Albuquerque, NM
2.5 ppb(25% of limit)
Sacramento, CA
2.3 ppb(23% of limit)
Miami, FL
2 ppb(20% of limit)
Houston, TX
1.8 ppb(18% of limit)
Las Vegas, NV
1.4 ppb(14% of limit)
Fort Worth, TX
1.2 ppb(12% of limit)
Long Beach, CA
1.1 ppb(11% of limit)
Portland, OR
0.8 ppb(8% of limit)
Arlington, TX
0.6 ppb(6% of limit)
Seattle, WA
0.4 ppb(4% of limit)
Frequently Asked Questions

What level of arsenic in water is safe?

The EPA MCL is 10 ppb, but the MCLG (health goal) is zero. Any level of arsenic exposure carries some cancer risk. The 10 ppb standard balances health protection with treatment feasibility. California's Public Health Goal is 0.004 ppb — roughly 2,500 times stricter than the federal limit.
Which states have the most arsenic in water?

Arsenic in groundwater is most common in the western US (Arizona, Nevada, California, Oregon), parts of the Midwest (Iowa, Wisconsin), and portions of New England (Maine, New Hampshire). It tends to be higher in groundwater systems than surface water, and is driven by the geology of the underlying bedrock.
Does boiling water remove arsenic?

No. Boiling concentrates arsenic as water evaporates, making it worse. Use a reverse osmosis filter or bottled water if your water contains arsenic above the EPA limit.
Can I shower in water with arsenic?

Yes. Arsenic is not absorbed through skin in meaningful amounts during normal bathing. Showering, bathing, laundry, and dishwashing are safe as long as arsenic levels are below 500 ppb. The health risk from arsenic is exclusively from ingestion — drinking and cooking.
Does a Brita filter remove arsenic?

No. Standard Brita pitchers use activated carbon, which does not remove arsenic. Refrigerator filters and basic faucet filters are also ineffective. For arsenic removal, you need a reverse osmosis system or a specialized adsorption filter certified to NSF/ANSI Standard 53 or 58.
How often should I test my well water for arsenic?

Test your well water at least once for arsenic. If none is detected, routine retesting is generally not necessary. If arsenic is found, test annually to track fluctuations. For newly drilled wells, retest after 6 months, as arsenic levels can vary during the initial period.
Is arsenic in rice related to arsenic in water?

Yes, but they are different exposure pathways. Rice naturally absorbs arsenic from soil and irrigation water, and is the most common dietary source of arsenic in the American diet. When drinking water arsenic exceeds 10 ppb, water becomes the larger exposure source; below that, dietary intake (especially rice) tends to dominate.

For drinking water level amounts of filtration, Berkey offers a flouride/arsenic filtration pair that works with the more limited abilities of the standard Black Berkey.
Filters few thousand gallons before replacement. Expensive. DO NOT buy from unauthorized online 'retailers' of any sort. Berkey has had a huge problem with chinnese counterfeits and Amazon, EBay , etc selling 'compatible' replacement filters.
They are also facing/have faced litigation from golddiggers testing counterfeit filters and attempting to force settlements for substandard filter performance.

Been dealing with this myself lately. The water level has been dropping in the aquifers due to extremely deep wells and huge amounts of use by commercial agriculture, primarily cows, and so our well needed to be deepened. The water before the deepening had been testing great for many years, but afterwards both the arsenic and fluoride tested too high for drinking water standards and possibly for irrigation too when it comes to fluoride. Perhaps it will change after 6 months, we'll see. In the meantime I've got the gardening on hold until I figure out something. It's been 3 months so far. Like arsenic, fluoride can be found naturally in well waters, and while a deeper well can prevent bacterial and other contamination from the surface, it often increases the levels of these things. Fluoride has not been considered an issue in this area in the past, so either the lab was wrong or something's changed.

We have an 'undersink' RO system certified to remove arsenic (but certification only covers arsenic V). We have labs for just arsenic and fluoride taken before and after our RO system at two different labs right now as a followup. The most common arsenic labs are total arsenic (3 & 5), so we're starting with that to test our RO system's effectiveness with our arsenic. If total arsenic is still too high, then we'll get the harder to find and much more expensive specific arsenic 3 and arsenic 5 tests to determine our options from there. I have a long history of multiple basal cell skin cancers being removed (20 over the last decade and a half), so it is important to me not to add more risk from arsenic in my drinking water. I'd prefer a Berkey for drinking water to maybe preserve more minerals, but thought they didn't work well enough for our water. Now that I'm reading Tommy's post I've just rechecked MyBerkey.com and confirmed they do have filters that claim to deal with that. I'll see what the results are here first and then maybe get a Berkey... wish they had a thing where you could test it and return if it doesn't filter enough, but seems their returns are on unopened things and I'd have to open it to test. I'd be okay with not being able to return the filters, but I'd want to be able to return the system.

Adding some info about arsenic to the tapwater.org info Susan posted:
Oregon’s arsenic guidance has 10–35 ppb water in a category where it recommends not using it for drinking, cooking, or washing fruits and vegetables, but allows other domestic uses including garden irrigation. It warns against long-term garden irrigation at 100–499 ppb because arsenic can build up in soil and be taken up by vegetables. Maine Extension says garden irrigation is considered unsafe at 100 ppb or higher, and for water below that level recommends drip/trickle irrigation, avoiding water contact with hard-to-clean leafy greens, and being cautious with root crops. It also notes that fruiting vegetables such as tomatoes and peppers tend not to move arsenic into the fruit as much. This is another good reason to reduce reliance on irrigation as much as possible.

The Arizona Gardenroots project found that homegrown vegetables took up arsenic. In its data lettuce, beans, onions, radishes, Brussels sprouts, broccoli, cabbage, beets, spinach, peppers, carrots, celery, and corn generally had higher arsenic than the FDA market-basket comparison, while squash, cucumber, and tomatoes generally had lower arsenic than the FDA comparison. It also found Asteraceae, such as lettuce, and Brassicaceae, such as radish, broccoli, Brussels sprouts, kale, and cabbage were among the top arsenic-accumulating plant families in that study. They still found the largest arsenic exposure route was drinking water, then incidental soil ingestion, with homegrown vegetable ingestion a smaller contributor, but it recommended soil testing and limiting Asteraceae and Brassicaceae vegetables as a precaution in that contaminated setting.

Then there's fluoride... adding to the reasons to reduce reliance on irrigation. People often think city & public water sources are the water with fluoride in it because some places add it in, but actually the levels in well water can be much higher than that... and too much fluoride can cause health issues. People think of children's teeth in terms of not enough fluoride and too much fluoride, and it's true they are affected, but too much fluoride can also negatively affect children's brains, and severely negatively affect people's bones at any age.

From the EPA's 2026 Fluoride Human Health Toxicity Assessment: Preliminary Assessment Plan and Literature Survey:

Fluoride exposure has been associated with both beneficial and harmful effects on human health, depending on the amount of exposure. At lower levels, fluoride has been shown to decrease the prevalence of tooth decay (dental caries/cavities), one of the most common chronic diseases among American children (CDC, 2024). Higher levels of fluoride exposure can result in harmful effects on permanent (adult) teeth called dental fluorosis in children, which can range from mild (small white striations or opaque areas) to severe (pitting) (U.S. EPA, 2010a). Additionally, a recent systematic review by NTP (2024) concluded that there is moderate confidence that exposure to fluoride at levels greater than 1.5 mg/L in drinking water is associated with lower IQ in children, with a similar finding based on fewer data and with greater uncertainty at lower levels of exposure (e.g., less than 1.5 mg/L in drinking water). Prolonged higher levels of fluoride intake are associated with an increased prevalence of bone weakening, called skeletal fluorosis, across all lifestages which can include brittle bones, increased risk of fractures, and crippling (severe bone abnormalities) (U.S. EPA, 2010a; Dean, 1942

The UN's Food and Agriculture Organization lists fluoride 1.0 mg/L as the recommended maximum concentration in irrigation water, while noting that fluoride can be inactivated by neutral and alkaline soils. The Canadian Council of Ministers of the Environment (CCME)’s agricultural guideline for fluoride in irrigation water is also 1000 µg/L, meaning 1.0 mg/L. California’s San Francisco Bay Basin Water Board's table of objectives for agricultural water supply lists fluoride 1.0 mg/L as the threshold and 15.0 mg/L as the limit, and it also lists arsenic 0.1 mg/L as the threshold and 2.0 mg/L as the limit.

Below is the tapwater.org page info on Fluoride info (like that info on Arsenic Susan Boyce posted above, but for fluoride). Note: the EPA says:

EPA does not make recommendations on adding fluoride to drinking water, since SDWA prohibits EPA from requiring the addition of any substance to drinking water for preventive health care purposes (Section 1412(b)(11)) (U.S. EPA, 2020). For communities that add fluoride to their water systems, the U.S. Public Health Service recommends an optimal fluoride concentration of 0.7 mg/L to provide protection against dental caries while limiting the risk of adverse effects such as dental fluorosis (U.S. Department of Health and Human Services, 2015). The decision whether or not to add fluoride to drinking water is made on a state or local basis

and

In the United States, fluoride in public water systems is regulated as a drinking water contaminant under SDWA. EPA’s current fluoride National Primary Drinking Water Regulation (NPDWR) was established in 1986 (U.S. EPA, 1986b) with a maximum contaminant level (MCL) and maximum contaminant level goal (MCLG) of 4 mg/L to protect against crippling (stage III)1 skeletal fluorosis. EPA also established a secondary MCL of 2 mg/L to protect against cosmetically objectionable dental fluorosis in children. Secondary MCLs are non-enforceable levels which are set at a level that does not present a risk to human health but may address aesthetic, technical, and/or cosmetic considerations.

I've discovered that it's not just private wells that are not tested for fluoride unless individuals decide to, nor are they required to, but it's also any public water system that does not actually add fluoride to its water supply or have any history of fluoride levels exceeding the NPDWR, unless the state has some other monitoring schedule requirements which is rare. This means that fluoride may never have been tested even in public drinking water supplies if they don't add fluoride to the water, which is no longer recommended. Things are more lax for irrigation waters than drinking waters in general. I'm also not sure whether the food supply is tested for excess fluoride, so it's hard to know if getting things others grow is any better or worse than what I'd be growing fluoride-wise. Ideally I'd be able to have water without too much of these things so I can grow my own food with it while I also try to use as little irrigation as possible. Then I'd know the food I'm growing is better off. That's my goal.

Thanks Matt for the link about using a bio-sand filter (BSD) for arsenic, here's one about using an altered BSD for fluoride (aluminum oxide coated biochar seemed to perform the best). I'm not sure how either could be practical for our garden as-is though, as their flow rate is so very low. I think I could adjust things for that if we could get them going and they work... I'm going to wait for the test results, and possibly for 6 month repeat tests before I decide what I'm going to try.

Okay, here's the tapwater info on fluoride as promised:

Fluoride

A mineral added to most US water systems to prevent tooth decay. Also occurs naturally in some groundwater.
Where does it come from?

Intentionally added during water treatment. Also from natural deposits and industrial discharge.
Health Risk

At recommended levels (0.7 ppm), strengthens teeth. Excessive levels above 4 ppm can cause bone disease and mottled teeth.
How to remove it

Reverse osmosis, activated alumina, and bone char filters can reduce fluoride. Standard carbon filters do not remove fluoride.

Fluoride is unique among drinking water contaminants because it is intentionally added to most US public water systems to prevent tooth decay. About 73% of Americans on public water systems receive fluoridated water at a target level of 0.7 parts per million (ppm).

The EPA's Maximum Contaminant Level for fluoride is 4 ppm, and the secondary (cosmetic) limit is 2 ppm. Natural fluoride levels in groundwater can sometimes exceed these limits.
Benefits and Risks of Fluoride

Benefits (at 0.7 ppm):

   Reduces tooth decay by 25% in children and adults
   Strengthens tooth enamel
   Considered one of the top 10 public health achievements of the 20th century by the CDC

Risks (at excessive levels):

   Dental fluorosis — white spots or mottling on teeth (cosmetic, above 2 ppm)
   Skeletal fluorosis — bone pain and damage (above 4 ppm, with long-term exposure)
   Some studies suggest possible links to thyroid effects and neurodevelopmental concerns at high levels

How to Remove Fluoride

If you prefer to reduce fluoride in your drinking water:

   Reverse Osmosis: Removes 90-95% of fluoride — the most effective method
   Activated Alumina: Designed specifically for fluoride removal
   Bone Char Carbon: A specialized carbon filter effective for fluoride
   Distillation: Effective but slow

Important: Standard activated carbon filters (Brita, PUR, etc.) do NOT remove fluoride.
Fluoride Levels in US Cities

Based on verified municipal water quality reports (Consumer Confidence Reports) from 47 cities.
Detected Within Limits (47)
San Jose, CA0.83 ppm(42% of limit)
Los Angeles, CA0.8 ppm(40% of limit)
Long Beach, CA0.72 ppm(36% of limit)
Sacramento, CA0.7 ppm(35% of limit)
Oakland, CA0.7 ppm(35% of limit)
New York City, NY0.7 ppm(32% of limit)
Philadelphia, PA0.624 ppm(31% of limit)
Jacksonville, NC1.2 ppm(30% of limit)
Baltimore, MD1.17 ppm(29% of limit)
Mesa, AZ1.11 ppm(28% of limit)
Jacksonville, FL1.06 ppm(27% of limit)
Miami, FL1 ppm(25% of limit)
Columbus, OH0.96 ppm(24% of limit)
Albuquerque, NM0.93 ppm(23% of limit)
Fort Worth, TX0.9 ppm(23% of limit)
Omaha, NE0.83 ppm(21% of limit)
Washington, DC0.8 ppm(20% of limit)
Chicago, IL0.76 ppm(19% of limit)
Kansas City, MO0.746 ppm(19% of limit)
Charlotte, NC0.74 ppm(19% of limit)
Seattle, WA0.7 ppm(18% of limit)
Boston, MA0.7 ppm(18% of limit)
Minneapolis, MN0.7 ppm(18% of limit)
Tulsa, OK0.69 ppm(17% of limit)
Louisville, KY0.685 ppm(17% of limit)

+ 22 more cities with detectable levels
Frequently Asked Questions
Is fluoride in water safe?

At the recommended level of 0.7 ppm, major health organizations (CDC, WHO, ADA) consider fluoride in water safe and beneficial for dental health. The EPA MCL of 4 ppm is the enforceable limit. Natural fluoride above 2 ppm may cause cosmetic dental fluorosis.
Does a Brita filter remove fluoride?

No. Standard activated carbon filters including Brita, PUR, and most pitcher filters do not remove fluoride. To remove fluoride, you need a reverse osmosis system, activated alumina filter, or bone char filter.
Which cities have the most fluoride?

Most US cities add fluoride at 0.7 ppm. Some areas with naturally high fluoride include parts of the Southwest, the Great Plains, and areas with volcanic geology. Check your city page on TapWater.org for specific levels.