How to Test for Arsenic in Water: 2023 Ultimate Guide

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If you’re a private well owner, you may be at risk of harmful arsenic exposure in your drinking water.

Since 2008, arsenic has been detected in about 40 percent of new wells in Minnesota. It’s easy to imagine that this figure could be similar, or even worse, if a larger-scale study was conducted on the whole of the US.

Luckily, removing arsenic from your drinking water is possible. However, you need to test your water for arsenic to understand whether you have an issue with this contaminant in the first place.

In this guide, I’ll be sharing the information you need to know about arsenic, including how it gets into wells, how to find out if you have arsenic in your water, how to test for it, and what to do if your water tests positive for high arsenic levels.

πŸ€” How Does Arsenic Get Into Well Water?

There are several ways that arsenic can get into well water. Most commonly, arsenic leaches into well water through contaminated groundwater sources.

Arsenic levels in groundwater can vary from one area to the next. While arsenic is largely a natural contaminant, it has been used in some farming and industrial activities in the past. For instance, it was a wood preservative at one point, and it has also served as a pesticide ingredient.

arsenic in groundwater map
Source:Β United States Geological Survey (

Arsenic is present in rocks and soils. When these soils come into contact with groundwater, arsenic leaches into this water, and is carried to new locations. This water can end up inside a well aquifer, resulting in well water contamination.

If you’re not sure whether arsenic has been detected in your state’s groundwater, I recommend Google-searching the subject. If arsenic is a known issue, you’ll find information about it online.

❔ How Do I Know if I Have Arsenic in My Water?

It’s not easy to guess whether your water contains arsenic, as most types of arsenic are tasteless, odorless and colorless.

Arsenic may be present in your private well without you even knowing. Unlike other well contaminants, it won’t stain surfaces, and it has no obvious characteristic that makes it easy to detect.

Unfortunately, most people aren’t aware that they have arsenic in their water unless they test for it – or until they experience symptoms of arsenic poisoning.

You’re not required by federal law to test your private well or treat your water to remove contaminants, so it’s your responsibility to make sure that your water’s levels of arsenic are very low, and that you’re not putting yourself and your family at risk by drinking from your well.

Remember, arsenic levels can vary widely, even from well to well. So, if your neighbor’s well has low levels of arsenic, or no arsenic at all, it’s still important that you test your own.

πŸ’‘ Should I Test My Water for Arsenic?

The U.S Environmental Protection Agency (EPA) has set a Maximum Contaminant Level of 10 parts per billion (PPB) for arsenic. This applies to public water supplies, not wells. However, you may have your own local laws that apply to well owners, too. For instance, New Jersey and New Hampshire require that well owners ensure that their water’s arsenic levels are below 5 PPB.

You won’t be sure of whether you need to reduce your water’s levels of arsenic until you know how much arsenic your well contains. Getting your water tested for arsenic will ensure that you are safe from the dangers of long-term arsenic exposure.

water testing with tap score

According to, arsenic can be dangerous even at lower levels.

Low-level arsenic exposure over a long period of time puts you at risk of kidney and liver damage, skin changes, and a decrease in white and red blood cells, leaving you fatigued and more susceptible to infection.

Exposure to high levels of arsenic in your drinking water is more dangerous, and can cause diarrhea, vomiting, nausea, skin rashes, muscle weakness, and more. Arsenic can be fatal when consumed in high enough amounts.


The only way to avoid arsenic exposure is to carry out a well water test for this contaminant. As it occurs naturally, there’s just no way to know whether your drinking water has elevated arsenic concentrations without testing your water supply.

πŸ“Œ How to Test for Arsenic in Drinking Water

Arsenic is a contaminant that only really poses a problem in wells, not public water supplies. For this reason, your options are more limited when it comes to testing for arsenic in your well.

You’ll struggle to find a DIY water test kit that can test specifically for arsenic. Arsenic testing is more complex, and it’s worth spending more money on a test that will deliver the most accurate results. That’s where accredited laboratory testing comes in.

Accredited Laboratory Testing

There are hundreds of certified laboratories in the US that offer accurate, informative arsenic testing for well owners.

This type of water testing requires that you take a water sample and post it directly to the laboratory. Most laboratories will send kits that contain a vial for collecting your water sample, and anything else that’s needed.

Once the lab has received your water sample, it will test the water for specific contaminants. You can expect to receive your arsenic test results back within 24 to 48 hours.

Laboratory water testing gives highly accurate, detailed results. Your arsenic test results will outline exactly how much arsenic your water contains in parts per billion (PPB). You may choose to test for other contaminants with health effects, which will give you a broader idea of what your well contains.

My recommended certified lab is Tap Score by SimpleLab. The Tap Score Essential Well Water Test is ideal for private wells, and tests for a broad range of common naturally occurring contaminants that affect water quality, including hardness, turbidity, bacteria, iron, mercury, zinc, and more.

tap score water testing

πŸ™‹ What Can I Do If My Water Tests Positive for High Arsenic Levels?

If you discover that your drinking water contains arsenic, your next step is to look at water treatment options that can remove arsenic as soon as possible.

Here’s what to do if you discover arsenic in your drinking water:

Switch To Bottled Water

If your water contains more than 10 PPB of arsenic, you shouldn’t be drinking it or using it for cooking, brushing your teeth, or any other purpose that could result in you swallowing arsenic.

Switch to bottled water while you look at your treatment options. Your health is important enough to warrant the temporary cost of shop-bought water.

Consider Reverse Osmosis

One of the best water treatment solutions for arsenic is reverse osmosis. An RO filtration system can remove almost every single dissolved solid in drinking water, including metals, chemicals, and microorganisms.

Reverse Osmosis

You can buy a reverse osmosis system for under-sink or whole-home use, and you can be certain that it will offer arsenic removal to below EPA guidelines.

RO units can be quite expensive, and I’d recommend purchasing a point-of-use system, which costs a fraction of the price of a whole-home system. You may want to eliminate arsenic from the water that gets used all over your home, but this can prove very expensive with RO.

Use Distillation

Another highly effective water treatment method is distillation. A distiller boils water until it evaporates, then condenses it into a clean container. This treatment system is usually set up on a kitchen countertop, and can be used to treat drinking water at a relatively low cost.

Distillers require electricity to operate, and they’re certainly not the quickest means of purification. It can take a distiller over an hour of effort per liter of water produced, and between 4 and 6 hours for a single gallon of water to be distilled.

imber isla distiller performance

However, distillation is one of the most affordable means of treatment, which, for many people, makes the lengthy purification process worth the wait. You can buy a distiller for less than $300, and you won’t have to pay to replace its filters, as you would with RO systems.

Look Into Additional Filtration Methods

There are several other methods that can be used to filter arsenic out of your drinking water. Anion exchange systems can be used to replace arsenic with a non-toxic impurity, like sodium. Activated alumina is also effective in adsorbing arsenic. The advantage of both of these systems is that they can provide filtered water for whole-home use, rather than just drinking water.

To learn more about the methods of removing arsenic from well water, check out my full guide here.

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