Arsenic Water Treatment

Arsenic occurs naturally in groundwater and may also be present from human activities. The only way to know if your drinking water well has arsenic is to test it. If you do have arsenic in your well water, there are water treatment options to remove it.

Should you be concerned about arsenic in your well water?

Yes. EVERYONE should test their well water for arsenic and other contaminants.

Many people in this country are exposed to low levels of arsenic through food, water and other sources that may increase their risk of diseases like cancer, heart disease and diabetes later in life.

If you are a Private Well Owner and your water test shows you have arsenic, read this page to learn about water treatment options. Then be sure to talk with a professional about what option makes sense for you.


Get What Your Family Needs

  • Talk with your state private drinking water well program, your state health department or your local health department for more information on removing arsenic.
  • Review the information in “What should you do if you have arsenic in your well water?” below.
  • Talk to a water treatment professional to choose a system that works for your unique water chemistry and your budget. If your arsenic levels are below 250 ppb (0.25 mg/L), then a simple Point of Use (POU) filter at your kitchen sink is a good option.
  • If you have very high levels of arsenic (greater than or equal to 250 ppb or 0.25 mg/L), consider getting a system that treats all water in the home.

Plan Ahead

  • Learn about treatment options through the Be Well Informed online tool.
  • Talk with your water treatment professional so that you know how your system works.
  • Make a plan for how you’ll take care of your treatment system.
  • Once your treatment system is running, test your water again to make sure it’s working to remove arsenic, and be sure to test your water every year.

What should you do if you have arsenic in your well water?

If your water test shows that your well water has arsenic above 5 parts per billion:

For the short-term, use bottled water for:

until you are able to install a permanent arsenic removal system.

  • Some Pitcher Filters are certified for arsenic removal and are a good interim solution. Check for certification by the National Sanitation Foundation and be sure the pitcher reduces arsenic to below 10 ppb. Change filters regularly to ensure continuous arsenic removal.
  • Carbon-based water pitcher filters do not remove arsenic.
  • Boiling your water does not remove arsenic.

Talk to a water treatment professional about long-term treatment solutions:

There are two types of arsenic water treatment systems, described below. No matter what option you choose, make sure that it carries a seal from the National Sanitation Foundation (NSF). Treatment systems without the NSF certification may not lower the amount of arsenic in your water. Ask a water treatment professional to show you the certification seal on the system before you buy it, or look up the system you’re thinking about on the NSF website and scroll down to arsenic. Be sure the system you choose reduces arsenic to 5 ppb or lower.

The two types of systems are:

Point of Use Treatment – This option treats the water at just one tap – often at the kitchen sink. This is less expensive, and is typically a good option if testing shows you have arsenic levels up to 250 ppb (0.25 mg/L). With this option, all the water for drinking and cooking should come from this tap.

Point of Entry Treatment – This option treats all of the water coming out of all of the taps in your house. These systems can be costly to purchase and to maintain, so be sure to request and review the maintenance costs also. Point of Entry treatment systems may be necessary if your levels are very high (greater than 250 ppb or 0.25 mg/L).

Use Be Well Informed With Your Test Results

The Be Well Informed online tool will help you interpret your water testing results. Enter the results of your water test into the tool and it will provide an easy-to-understand explanation of water treatment options and health risks based on your unique water characteristics. You don’t need to live in New Hampshire to use this tool.

A Summary of Arsenic Levels

  • 0 ppb EPA’s Maximum Contaminant Level GOAL for arsenic in public water (not enforced).
  • 2 ppb Average arsenic levels in U.S. drinking water.
  • 5 ppb New Jersey’s and New Hampshire’s Maximum Contaminant Level (enforced in public water systems). More cautious than federal limits.
  • 10 ppb EPA’s Maximum Contaminant Level (enforced in public water systems). Set in 2001 based on cost and feasibility.
  • 1000-3000 ppb fatal levels of arsenic exposure.

Is There Regulation of Arsenic in Water?

Yes. The U.S. Environmental Protection Agency requires public water systems to reduce arsenic levels in water to a maximum of 10 parts per billion or lower. Federal law does not require private well owners to test or treat their water for contaminants, although local or state requirements may exist where you live. It is your responsibility to learn what is in your water and take steps to be sure your water is safe to drink. also provides helpful information on well maintenance and treatment.

You could also consider:

Connecting your house to a public water supply. With this option, your water is checked and treated for arsenic and other contaminants by your town or city. This process could be costly, though, and not all homes can be linked to public water.

Installing a new well or deepening your well. This option could give you better water quality, but it can also be costly. You may not know until the well has been drilled if the water has arsenic in it, and you may still need an arsenic treatment system. Find out about arsenic levels in groundwater in your area if this is an option you are considering.

What’s next after you install an arsenic treatment system?

Now that you’ve installed a system, conduct a second arsenic test to make sure the treatment is working. Test the water from your tap every few months until you know how your system needs to be maintained and then test yearly to make sure the system is still removing arsenic. Follow the directions to maintain your water treatment system, and contact a water treatment professional if you’re worried that it’s not working properly.

“If there’s arsenic in your well water, you need to take action now. Research your options for getting your water’s arsenic levels as low as possible. Choose an option that makes sense for your home, your budget, and your unique water. For most households, a fairly inexpensive system installed under your kitchen sink will work fine to get arsenic out of your drinking water.”

Cynthia Klevens, New Hampshire Department of Environmental Services

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