Frequently Asked Questions - Testing your well and making sense of the results

Why should we have our well tested for arsenic?
  • Arsenic has no smell, taste or color when dissolved in water, even in high concentrations.
  • Testing a water sample is the only way to know how much arsenic is present in a well.
  • EPA regulations and testing are limited to public water sources, not private wells. If your family gets their drinking/cooking water from a private well, you should have your water tested for arsenic. 
Where can we get our well water tested?
  • It is not recommended that homeowners go out and buy a home test kit to check arsenic levels in their water.
  • NJDEP's Office of Quality Assurance provides lists of certified labs and they can be reached by phone at 609-292-3950 for more information.
  • The labs listed on the NJ Arsenic Awareness Testing Options page are certified to sample private wells and analyze drinking water for arsenic by the most sensitive method available (EPA 200.8). Clicking on the laboratory name will bring you to their website
Are there any discounted testing options available?

  • Raritan Headwaters Association offers discounted water tests for a wide variety of pollutants to individual watershed residents and also partners with participating municipalities on designated test days. 908-234-1852, x401

     

Should we test for anything besides arsenic?
  • If your well water has not been tested within the past 5 years county health officers recommend requesting testing for the full set of Private Well Testing Act contaminants. 
  • If your well water has ever exceeded state standards for any of the contaminants it should be tested yearly for those contaminants, including where treatment systems have been installed.
  • Residents of every county where arsenic may be an issue (Bergen, Essex, Hudson, Hunterdon, Mercer, Middlesex, Morrris, Passaic, Somerset, Sussex, Union, and Warren) should also test for total coliform, e. coli if positive for total coliform, nitrate, iron, manganese, pH, VOCs, lead and gross alpha in addition to arsenic. 
  • Yearly tests for total coliform, e. coli if positive for total coliform, and nitrates are recommended. 
What do test results mean?
  • In New Jersey, the standard for arsenic is 5 micrograms per liter (abbreviated as "μg/L"). If arsenic levels are greater than 5 micrograms/liter, we encourage the use of bottled and/or properly treated water for all drinking and cooking, and encourage the installation of a treatment system.
  • Importantly, a negative test for arsenic does not mean that your water is safe with respect to other water quality parameters.
What does Maximum Contaminant Level (MCL) mean?
  • The MCL is an enforceable standard for public water systems regulated under the Safe Drinking Water Act. Private wells are unregulated and owners are responsible for managing the safety of their own drinking water; therefore, this standard only serves as a guideline value. Private well users must decide for themselves what concentration of arsenic in their drinking water is acceptable.
  • The Federal MCL for arsenic is 10 μg/L, chosen in 2001 by the Environmental Protection Agency (EPA) using discretionary authority to consider the costs of treating publicly supplied water to meet this standard. The State of New Jersey has adopted a lower MCL of 5 μg/L, the most protective in the nation. However, arsenic is a known carcinogen; therefore the EPA also set an MCL-Goal for arsenic of 0 μg/L, meaning there is no level of arsenic in drinking water that can be considered safe.
  • The risks from drinking water with arsenic at the federal MCL of 10 μg/L are significantly higher than for other carcinogenic drinking water contaminants at their MCL.
What does it mean that the maximum contaminant level goal for arsenic is 0 mcg/L in drinking water?
  • The maximum contaminant level goal (MCLG) is defined by USEPA as the level of contaminant in drinking water below which there is no known or expected risk to health and which allows a margin of safety. Because arsenic is a known human carcinogen via drinking water, the USEPA has determined that the maximum contaminant level goal is zero for arsenic in drinking water.
  • The MCLG is usually lower than the Maximum Contaminant Level (MCL). The MCL is the highest level of a contaminant that is legally allowed in drinking water.  MCLs are set as close as feasible to the MCLGs. For arsenic, the New Jersey MCL is 5 mcg/l. 
What forms of arsenic are found in New Jersey well water?
  • In New Jersey well water there are two common forms of arsenic that need to be removed by water treatment, Arsenic 3 and Arsenic 5.
  • Arsenic 3 is much more difficult to remove from well water than Arsenic 5 because Arsenic 3 has a neutral charge.
    • There is no simple and affordable test commercially available to determine which arsenic species is present so the species of arsenic present is usually unknown, though there is a rule of thumb that can help (See FAQ below).
  • The New Jersey Geological and Water Survey estimates that 20% of New Jersey wells with arsenic above the Maximum Contaminant Limit (MCL) of 5 micrograms/liter (mcg/L) have significant concentrations of Arsenic 3. 
Is there any way to determine which arsenic species is in my water (Arsenic 3 or Arsenic 5)?
  • There is no simple and affordable test commercially available to determine which arsenic species is present so the species of arsenic present is usually unknown. 
  • There is an Arsenic Speciation "Rule of Thumb" developed by the New Jersey Geological and Water Survey and Rutgers University that can be used to determine if Arsenic 3 may be a factor or not.
  • The Arsenic Speciation Rule of Thumb works by answering these two questions:
    • Are the Iron or Manganese concentrations in the untreated well water greater than 50 micrograms/liter (mcg/L)?
    • Is the Dissolved Oxygen concentration in the untreated well water less than 1.0 milligrams/liter (mg/L)?
  • If the answer to each question is "no" it is very unlikely that the water contains a significant concentration of Arsenic 3. 
  • If the answer to either question is "yes" then Arsenic 3 is likely present at a concentration greater than 3 mcg/L and therefore a serious factor in water treatment selection. In this case, a confirmatory Arsenic 3 test by arsenic speciation cartridge or laboratory analysis is recommended before spending extra money on treatment components to convert Arsenic 3 to Arsenic 5.