As a professional home inspector, I've often discussed the risks of radon gas in the air, a common health hazard in homes. But there's another, less talked-about risk: radon in water. This can be a serious health issue, especially when the radon-laden water releases the gas into the air during everyday use, adding to the home's overall air radon levels.

The Environmental Protection Agency (EPA) warns that exposure to radon in drinking water may increase the risk of cancer, particularly lung cancer. Radon, a radioactive gas that you can’t see, taste, or smell, forms from the natural decay of uranium in the soil. It's the second leading cause of lung cancer after smoking. When radon enters a home, it raises the risk of lung cancer for its occupants, especially smokers.

Typically, radon sneaks in through cracks or gaps in the basement or crawl space. However, radon in water, especially well water, is another concern. Imagine taking a hot shower. The water vapor produced releases tiny radon particles into the air, which we can then breathe in.

It's not just showers that can have this effect. When you run a washing machine with hot water, about 98% of radon in the water is released into the air. Even with cold water, it's around 93%. A hot shower, on the other hand, releases about 72% of the radon. These numbers make it clear that radon in water is something we can't ignore, considering the health risks involved.

WIN Home Inspector checking Radon in tap water

Continuous radon monitors are tools I, and other home inspectors, often use. These devices provide an hour-by-hour graphical representation of a home's radon levels over 48 hours or more. Such detailed data can reveal whether high radon levels correlate with water usage in homes served by wells. This can be a crucial step in identifying a radon in water issue. In our experience, radon from groundwater is a less common problem than radon gas from the soil, but it's still a concern.

Public water systems, which often source water from wells, regularly test for radon and other contaminants. However, homes with private wells rarely undergo such testing, potentially posing a greater risk to their occupants.

Regarding radon concentrations, there's an estimated 10,000:1 ratio of radon in water to radon in air. This means a waterborne radon concentration of 10,000 pCi/L could contribute to an air radon level of about 1 pCi/L. In homes with well water, less than 1% of air radon typically comes from the water.

Testing for radon in water isn't as common in some areas due to low demand. The testing process involves collecting a large water sample in a container, then capturing a sample in a vial under the running water to avoid air bubbles. This sample is then sent to a certified lab for analysis.

Radon in water can be remediated using diffused bubble aeration or granulated activated charcoal systems, installed where the water enters the home. Both methods can be somewhat costly, but they are effective in reducing radon levels.

In summary, while radon in air is a well-known issue, radon in water is an equally important aspect of home safety. As a home inspector, I emphasize the importance of testing and mitigating radon in both air and water to ensure a healthy living environment.

Author Bio:

Pat Knight A former home inspector, Pat serves as the Director of Training and Licensing for WIN Home Inspection, Pat has been in the inspection services industry for over 30 years and is an expert in performing and teaching 35+ essential services.