The ISO 9697 standard specifies a test method for the determination of total beta radioactivity in water by using the thick source method. This method measures the total beta radioactivity in water samples by using thick source samples for liquid scintillation counting. The standard is suitable for the detection of total beta radioactive pollution in water quality monitoring and is widely used in the fields of environment protection, public health and nuclear energy. This method can effectively evaluate the level of beta radioactive pollution in water bodies to ensure water quality safety and environment protection.