The ISO 13164-3 standard specifies the Measuring method for the content of radon-222 in water quality, using the radon measurement method (radon fugitive method). This method determines the concentration of radon-222 in water bodies by measuring the amount of radon fugitive in water samples. Radon-222 is a naturally radioactive gas that is commonly found in water sources such as groundwater and well water. Long-term exposure to high concentrations of radon gas may pose a health hazard. This standard provides an accurate and reliable radon-222 detection technology, providing an important tool for water quality monitoring. It can help assess the radioactive contamination of water sources and ensure the safety of water quality, especially in areas where radon concentration needs to be controlled.