arsenic in wel water Harvard, ma

Arsenic in Well Water


Approximately 90 percent of Harvard’s residents get their drinking water from a private well, but an estimated 20 percent of private wells in Massachusetts produce water that exhibit unhealthy levels of naturally occurring arsenic in well water.  Even more wells produce water with elevated concentrations of radon for which treatment is recommended. Wells that have not been properly maintained may produce water contaminated with bacteria and other contaminants. Inspecting your well and testing well water is the best way to make sure that your water is clean and safe to drink.

Arsenic in well water may occur naturally and is a tasteless, odorless and colorless contaminant. Other activities that could have left arsenic residuals include apple orchard spraying, coal ash disposal, and the use of some pressure treated wood. Harvard, MA homeowners are often surprised when they get their laboratory water test results back and see they have arsenic in their water. While there are serious health threats associated with ingestion, there are effective and safe methods for removing arsenic in well water. For detail on potential health affects, see the link at:

remove arsenic from water in Harvard   The two primary forms of Arsenic in well water are AS III and AS V. Many Arsenic removal media have a low capacity for removing Arsenic III from the water, therefore,converting it to AS V for removal is a common approach. Therefore, determining the ratio of AS III versus AS V in the water is critical. This will allow the design and implementation of a water treatment system that will effectively remove it from the water. There are methods to oxidize Arsenic III and convert it to AS V for ease of removal.

twin arsenic ozone filter Harvard, MA

Twin Arsenic system with Ozone


Water testing for Arsenic in well water Harvard, MA

Having a complete laboratory water test and analysis, including parameters that can negatively impact arsenic removal media, is critical to a well designed, safe water treatment system that will remove arsenic in well water.  pH can significantly affect Arsenic media performance along with other competing ions such as Iron, Manganese, Hardness, Vanadium, Sulfate, Phosphate, Silica, Total Dissolved Solids, Suspended Solids and Hydrogen Sulfide. For a full article on this topic which we’ve had published in Water Technology Magazine, go to our publications section and click on the Arsenic removal article at


Water meter for arsenic in well water monitoring

Determining water usage is also critical to designing an effective removal system that will have the proper capacity.  Key information would include well pump size, well pump flow rate, size of the incoming water line, number of residents in the home, the number of bathrooms, space availability for equipment installation, electrical availability and water discharge location or restrictions, among others.


A couple of key components for consideration when designing this type of system include:

  1.  Utilizing a meter to track flow rate and total gallons processed is critical to determine the home’s water demand.
  2.  Gallons used readings also assist in uncovering any potential leaks in the home such as running toilets, which will unnecessarily prematurely deplete the arsenic media’s capacity.


As this contaminant is a tasteless, colorless and odorless, it is particularly important to have two tanks in series in case the first tank is depleted prior to scheduled service with your water treatment company. Service should be scheduled at intervals determined by the water use tracking data accumulated.This combined with appropriate water testing intervals are added safeguards to prevent Arsenic from getting into the treated water entering the home.

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H2O Care is an established Massachusetts based water testing & filtration company, formed in 1989 with offices in Stow, MA & Middleton, MA. The Company has been published multiple times in Water Technology Magazines – see  Contact us at or 800-539-1100.