How to Remove Radon from Water

On this page (9 sections)

1. How do you remove radon from water?
2. What should you do before choosing a treatment system?
3. How does aeration treat radon in water?
4. How does a GAC system treat radon in water?
5. Can reverse osmosis remove radon from water?
6. How do you choose a radon in water treatment system?
7. How can you check whether treatment worked?
8. What other safety steps belong near a water treatment system?
9. What is the safest next step for radon in water?

Aeration and granular activated carbon (GAC) are the main methods used to reduce radon dissolved in water. Test your water first, then choose a properly sized system with help from a qualified water treatment professional.

Radon can enter water from underground sources, especially private wells. When water is used for showering, washing, or cooking, some dissolved radon can escape into indoor air, so the treatment decision should consider both the water and the home.

How do you remove radon from water?

Treat the water with an aeration system or a GAC system. The best choice depends on the water test, system design, installation space, ventilation, and upkeep.

Aeration transfers radon from water into air and vents that air outdoors. GAC uses carbon media to capture radon as water flows through it; the media eventually needs replacement and can require careful handling.

Treatment usually belongs where water enters the home, before it reaches taps and appliances. A professional can review your water test, plumbing, and site conditions to recommend a system.

What should you do before choosing a treatment system?

Get a water test that measures radon, then review the result with a qualified professional. A test provides the evidence needed to choose treatment and determine whether a follow-up test is needed after installation.

A home air test does not measure radon in water. The First Alert Radon Gas Test Kit is for testing radon gas in indoor air, so it can help with a separate air question but does not test water.

Use a lab or testing service that can handle water samples and follow its collection and shipping instructions. Ask local or state health agencies for approved testing options and any guidance for private wells.

Does radon in water need treatment if indoor air is also a concern?

Test indoor air and water separately when both may be sources. A water treatment system addresses radon in the water supply, while an air mitigation system addresses radon entering the home through other paths.

The U.S. Environmental Protection Agency explains that radon in household water can add to indoor air levels, but most radon in homes comes from soil gas.

Its radon in drinking water guidance describes testing and treatment considerations.

Don't use a water result alone to estimate indoor air exposure. A qualified radon professional can help interpret separate tests and determine which source needs attention.

How does aeration treat radon in water?

Aeration strips dissolved radon from water by bringing the water into contact with air. The system then sends the radon-bearing air outdoors through a properly designed vent.

Common designs use a tank or chamber to disperse water into air, giving radon a path out of the water. System designs vary, so a professional should assess the water flow, vent path, and location before installation.

The main advantage is that aeration transfers radon out of the water rather than holding it in filter media. Venting and maintenance still matter, and the outlet should be placed to keep exhaust away from windows and occupied areas.

What are the tradeoffs of aeration?

Aeration needs space, electrical or mechanical components in many designs, and a safe outdoor vent. Ask who will inspect the system and what maintenance schedule applies before you choose one.

The design may need to manage water droplets, sediment, or other water quality issues. Ask whether pretreatment is needed and how the unit will be serviced if flow or water quality changes.

Avoid trying to build a treatment device from a fan or open tank. A purpose-designed system and qualified installation help control where radon-laden air goes.

How does a GAC system treat radon in water?

A GAC system passes water through activated carbon, where radon is captured by the media. The carbon must be replaced according to the system maker's instructions and the conditions measured by a professional.

A GAC unit may fit homes where a suitable filter can be installed on the water line. Its operation depends on the system's capacity and the household's water use, so sizing should follow professional guidance.

Because the carbon holds radioactive material as it captures radon, ask about safe replacement and disposal before selecting this approach. Don't handle or discard used media without following the maker's and local authorities' instructions.

What should you ask about carbon replacement?

Ask how often the media needs service, who can replace it, and how spent carbon should be handled. Get those details before installation so ongoing costs and responsibilities are clear.

A system that is too small or overdue for service may not perform as intended. Keep service records and schedule follow-up water testing when recommended.

Can reverse osmosis remove radon from water?

Don't assume a reverse osmosis filter is a complete radon solution. Treatment depends on the unit and how it's installed, and whole-home radon treatment is commonly handled with aeration or GAC.

Point-of-use RO systems treat water at a particular tap, while water entering the house may still carry radon elsewhere. Read our explanation of whether RO removes radon before relying on it for this purpose.

For a broader comparison of system types and selection questions, see how to choose a radon water mitigation system. Ask a professional to confirm whether a proposed unit is designed and rated for the water condition you measured.

How do you choose a radon in water treatment system?

Match the system to your water test and get a written plan for installation, venting or media service, and retesting. Compare those practical requirements along with the purchase and upkeep costs.

Ask potential installers:

• Is this system designed for the radon level and water flow in my home?
• Where will radon leave the system, and how is exhaust routed?
• What routine maintenance or media replacement is required?
• How should spent carbon or other waste be handled?
• When should I retest the treated water?
• Does my plumbing or water quality call for pretreatment?

The Basement Watchdog 110 dB Water Alarm can help alert you to water near a sump or other monitored spot, which may be useful around equipment or a basement area. It detects water, not radon, and is not a treatment device.

Place the sensor where a leak or overflow could reach it, following the alarm instructions. A water alarm does not replace system inspection or radon testing.

How can you check whether treatment worked?

Retest the treated water using the method recommended by your local health agency or treatment professional. Keep the result with the system's service records and repeat testing on the advised schedule.

A new result can confirm whether the system is reducing radon under current conditions. Retest after significant plumbing or system changes, and whenever a professional or local guidance recommends it.

If indoor air levels are also a concern, test the air separately. For homes with monitoring needs, our guide to Radon Monitors with Alarm System: A Useful Guide explains what those devices can and cannot tell you.

What other safety steps belong near a water treatment system?

Keep carbon monoxide alarms in place if your home has fuel-burning appliances, and use water alarms where leaks could cause damage. These devices monitor different hazards and don't detect radon in water.

The First Alert Plug in Carbon Monoxide Alarm has a digital display, battery backup, and an audible alarm. Carbon monoxide is unrelated to radon, so this alarm cannot verify water treatment or radon levels.

Follow the alarm's placement instructions and local safety guidance. Use a radon water test and an appropriate treatment system for the issue discussed in this guide.

What is the safest next step for radon in water?

Start with a water test, then choose aeration or GAC with professional guidance based on the result. Plan for installation, venting or carbon replacement, and follow-up testing before you commit to a system.

Choose aeration if a professionally designed system can vent radon-bearing air safely outdoors. Consider GAC when the system and its media service plan suit your home and water use.

If your immediate question is equipment selection, read how to choose a radon water mitigation system. Keep any indoor air testing separate, because a water treatment system only addresses radon carried by the water.

Frequently asked questions

Can radon be removed from water?

Yes. Aeration and granular activated carbon (GAC) systems can reduce dissolved radon in water.

The right method depends on the water supply, treatment setup, and maintenance needs.

Test the water first, then ask a qualified water treatment professional to assess the results and recommend a system sized for your home.

Does boiling water remove radon?

Boiling is not a recommended household treatment for radon in water. It can release radon into indoor air as water heats, shifting the concern rather than managing it safely.

Use a properly selected treatment system and follow local public health guidance for testing and installation.

Is aeration or carbon better for radon in water?

Aeration is often considered when the goal is to strip dissolved radon from water and vent it outdoors, while GAC filters capture radon on carbon. Each method has different installation, ventilation, maintenance, and waste handling needs.

A water treatment professional can compare them for your test results and home.

Does reverse osmosis remove radon from water?

A point-of-use reverse osmosis unit may reduce some contaminants, but don't assume it is an effective radon treatment without system-specific evidence. Radon treatment is usually addressed with aeration or GAC at the point where water enters the home.

See our guide to whether RO removes radon for more detail.