Standard No. HJ 1075-2019 "Determination of water quality turbidity turbidity metering method" stipulates the turbidity metering method for the determination of surface water, groundwater and seawater turbidity. This standard aims to ensure the accuracy and comparability of water quality turbidity measurement in accordance with the "Law of the People's Republic of China on environment protection" and "Water Pollution Prevention and Control Law" to protect the ecological environment and public health. The determination method uses the principle of light scattering, using a stable Light source and Sensors to measure the intensity of scattered light in the sample. The results are expressed in NTU (scattered turbidity unit). The standard covers all steps and requirements from sample collection to measurement process, including specifications for the use of reagents and instruments, as well as precision and Precision evaluation methods. The standard applies to laboratories and environment monitoring units and is valid from June 30, 2020.