Arsenic is a semi-metal element which has no odor or taste. It typically enters drinking water from agriculture and industrial uses. However much of the arsenic found in groundwater is naturally occurring and comes from water dissolving arsenic from the geological formations surrounding the aquifers.

Arsenic is used in industries including wood preservation. It has also been used in paints, dyes, metals, drugs, soaps and semi-conductors. Due to more health affects being associated with arsenic it has been eliminated in most products.   Arsenic was also a main ingredient in some pesticides so it can be found in some agricultural areas. It can also be released into our water due to mining activities.


Health Effects

According to the EPA consuming water which contains arsenic over many years would result in skin lesions/rashes and circulatory problems. Arsenic has also been classified as a known carcinogen, so it can cause cancer.


The Maximum Contaminant Level Goals (MCLG) for arsenic is zero. EPA has set this level of protection based on the best available science to prevent potential health problems. Based on the MCLG, EPA has set an enforceable regulation for arsenic, called a maximum contaminant level (MCL), at 0.010 mg/L or 10 ppb. MCLs are set as close to the health goals as possible, considering cost, benefits and the ability of public water systems to detect and remove contaminants using suitable treatment technologies.

Keep in mind that some states may opt to adopt a more stringent MCL to further protect public health. For example the state of New Jersey has established an MCL of 0.005 mg/L or 5 ppb for arsenic.



According to the EPA the following treatment method(s) have proven to be effective for removing arsenic to below 0.010 mg/L or 10 ppb:

  • Adsorptive media
  • Ion Exchange
  • Coagulation/Filtration
  • Oxidation/Filtration
  • Point of Use and Point of Entry which utilize activated alumina or reverse osmosis