How to Test for Radon in Water: 2023 Ultimate Guide

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Radon is a gas that has no color and no odor. You can be exposed to radon in the air in your own home, as well as radon in your drinking water.

This gas can have dangerous health effects when consumed. If you’ve never tested your well water for radon before, I recommend doing so as soon as possible. It’s essential that you avoid radon exposure where possible.

In this guide, I’ll be sharing how to test for radon in drinking water, and what to do if you discover high radon levels in your well.

🚱 How Does Radon Get Into Well Water?

Radon is produced when uranium is broken down in the ground. Radon can be found in soils, and can dissolve and accumulate in groundwater sources.

If you live in an area with high underground radon levels, there’s a greater chance that this radon will end up in your well water. As groundwater seeps through the earth, it may pick up radon. This water could then make it into your well via the aquifer.

How Does Radon Get Into Well Water

⚠️ How Can You Determine if There is Radon in Your Water?

There is no way to visually determine whether or not your water contains radon. Radon is also odorless and tasteless. Whether it’s in the air or in your drinking water, you won’t know that you’re dealing with radon unless you test for it. 

It’s impossible to know, without testing, whether or not your drinking water contains radon gas. And of course, not all drinking water contains radon. When it comes to radon, you’re safer if your drinking water comes from a surface water source, like a reservoir or river, as any radon present will likely dissipate before it reaches your home. But if you get your water from underground it has an increased chance of containing radon.

I examine the best methods to test for radon in your water later in this guide.

🔎 Should I Test My Well Water for Radon?

It is recommended that you test your well water for radon if you’ve never tested for it before, even if you don’t believe your well is at risk of radon contamination. It’s especially important to test your water for radon if you’ve been alerted of radon contamination in your local area.

A report from the International Journal of Epidemiology says that drinking water containing radon gas poses a risk of certain cancers, especially cancer of the stomach.

The EPA estimates that around 168 people die from stomach cancer per year, caused by drinking radon in their water.

Stomach Cancer

What makes radon gas in water even more dangerous is that it escapes from water that is used in our homes and gets into the air.

According to the EPA, breathing in indoor air containing radon can cause lung cancer. Radioactive gas from the air can build up in your lungs, releasing energy as it breaks down, damaging your lungs and increasing your risk of lung cancer.

Radon in indoor air is estimated to be the second leading cause of lung cancer, and some 20,000 people in the US die every year from breathing in radon.

Radon gas is not as rare as you might think. If you want to protect yourself and your family from radon exposure, it’s important to test your air and water for radon.

🔬 How to Test for Radon in Drinking Water

Because radon has such dangerous potential health effects when consumed, I recommend investing more money in certified laboratory testing for this contaminant, so you know for sure that you’ll receive accurate results. You will struggle to find radon test kits for at-home-DIY use anyway, as it’s a difficult contaminant to test for.

Certified Laboratory Testing

Certified laboratory testing can provide the most detailed and comprehensive measurement of radon in water. There are hundreds of state-certified laboratories to choose from. Your local authority or health department may recommend the best laboratories in your local area.

For radon testing, I recommend using Tap Score by SimpleLab. The Radon Screen Water Test costs just over $50 and tests specifically for radon in drinking water. If results show that your water contains more than 300 to 10,000 pCi/L of radon (the suggested safe levels of radon), you can decide how to take action.

water testing with tap score

The Extended Well Water Test is a good option if you want to test for radon and other contaminants in your private well.

It costs more than $600, so it’s certainly not cheap, but it tests for hundreds of contaminants within specific categories: VOCs, metals and minerals, general characteristics, anions, pathogens, radionuclides, and SVOCs.

If you want peace of mind that your private well water is completely safe from harmless impurities, you’ll get that from the Extended Well Water Test.

tap score water testing
Tap score sampling kit

SimpleLab works by sending you a testing kit containing instructions and vials for taking a water sample from your water supply.

You’ll then post your water sample to SimpleLab, and they’ll test your water’s radon levels. The levels of radon detected will be noted on a report, which will be emailed to you within 5 days.

tap score example report
Tap score report

✔️ What Can I Do If My Water Tests Positive for Radon?

If your water tests positive for radon, it’s unlikely that you’ll be able to eliminate radon at its source. Instead, you can use a water treatment system to remove radon from the water delivered to your home from your private well.

The best treatment options to reduce radon or remove radon from your water are:

Granular Activated Carbon Filters

Granular activated carbon filters remove and retain dissolved radon particles by adsorption.

You can get carbon filters for under-sink applications, but I would recommend a whole-home system to prevent radon from getting into the air when you shower or use a water-based appliance.

These filters are affordable, making them an ideal long-term solution for greatly reducing drinking water radon levels. However, the problem with a granular activated carbon treatment system is that radioactive gas particles end up collecting on the surface of the filter media. This means that the filter cartridge may become a handling hazard, and you’ll need to be careful about how you dispose of it.

carbon water filter

Aeration Filters

The second water treatment method for reducing your exposure to radon is aeration. An aeration system works to remove dissolved radon by introducing air into the source water. When exposed to this additional air, radon gas will naturally be released from the water into the aeration tank. The tank will then exhaust the air, where it will be vented to the atmosphere.

Aeration is a highly effective radon removal treatment, and can prevent high levels of radon from entering your home. With this treatment, dissolved radon is released naturally, rather than collecting inside a filter cartridge. However, an aeration system could be costlier than simple carbon filtration.

If you’re also dealing with radon in your indoor air, you’ll need to consider a method of increasing airflow and properly ventilating your home. However, if your radon is only coming from your water, once you reduce radon in your water, the radon level in your indoor air will drop, too.

Aeration System

🧠 Frequently Asked Questions

Is radon gas more concerning in indoor air or water?

Airborne radon gas is more common than radon in water, which makes it more of a concern. When water containing radon comes into contact with indoor air, it will release most of the radon gas, which you’re at risk of breathing in. However, the remaining radon in water is still dangerous, and can still have serious health effects when consumed.

If you’re looking for a ballpark figure, any more than 300 to 10,000 pCi/L of radon in your water is considered potentially dangerous.

What is the federal drinking water standard for radon levels?

There is currently no federal drinking water standard for radon levels, but the Environmental Protection Agency (EPA) is in the process of enacting regulations for radon in public water systems.

Keep in mind that the Environmental Protection Agency does not regulate private wells, which is why it’s important to test your own well water for this contaminant and determine your own suitable water treatment if necessary.

Should I still test my drinking water for radon if it comes from a public water system?

A public water system should follow your state radon program and remove radon according to the standard set out there. You can check your annual water quality report to see how much radon is currently in your water supply.

If you want to learn more, you’ll first need to find out whether your provider gets your water from a surface source, such as a lake or a river, or an underground source. There’s a higher possibility that your water supply contains radon if it comes from groundwater. In this case, you can contact your water supplier and ask if they test and/or treat the water for radon according to your local radon program.

If your supplier doesn’t test for radon, you may want to do so yourself for peace of mind.

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