Arsenic in tap water: where it comes from and what actually reduces it
Most conversations about tap water focus on chlorine taste or hard water spots. Arsenic is a quieter subject, because you cannot taste it, smell it, or see it. It is also one of the contaminants regulators take most seriously, so it is worth understanding where it comes from and what to do about it.
How arsenic gets into water
Arsenic is a natural element found in rock and soil, and in many regions it leaches into groundwater on its own, with no human help. Industry adds to the picture: mining, smelting, and some legacy agricultural pesticides have left arsenic behind in soil and water. Private wells in areas with arsenic-rich geology are the most exposed, since well water is not treated or monitored by a utility. According to the Environmental Working Group, arsenic has been detected in drinking water supplies serving some 70 million Americans.
Why it matters
The EPA classifies arsenic as a carcinogen and limits it in public water systems to 10 parts per billion. Public health agencies associate long-term exposure above safe levels with skin changes, cardiovascular problems, and higher risk of several cancers. The concern is chronic, low-level exposure over years, which is exactly why testing matters even when water seems fine.
How to find out what is in your water
If you are on a municipal system, your utility publishes an annual water quality report, sometimes called a Consumer Confidence Report, that lists detected contaminants including arsenic. If you are on a private well, testing is up to you. State health departments and EPA guidance recommend testing well water through a certified laboratory, and many states run low-cost well testing programs.
What actually reduces arsenic
Not every filter touches arsenic, and this is a place to be picky. The treatment technologies used for arsenic include reverse osmosis, activated alumina, ion exchange, and distillation. What matters at the point of purchase is certification: look for systems certified under NSF/ANSI 58 for reverse osmosis, or under NSF/ANSI 53 with an explicit arsenic reduction claim, and read the performance data sheet to confirm it. A certified claim means the system was tested against the standard for that specific contaminant.
Where pitcher filters fit
Standard carbon pitcher filters, including our alkaline filter, are not certified for arsenic reduction, and you should be skeptical of any pitcher cartridge that implies otherwise without a certification to show. Our filter is built for a different job: it reduces chlorine taste and odor, adds calcium and magnesium minerals, and raises pH into the alkaline range in compatible Brita® pitchers. If a test shows arsenic in your water, the right response is a treatment system certified for arsenic, with a pitcher filter serving taste preferences alongside it, not instead of it.
The takeaway
You cannot detect arsenic with your senses, so let data lead. Read your utility report or test your well, compare results to the EPA limit of 10 parts per billion, and if you need treatment, buy certification, not marketing.