What is turbidity?

In various applications in wastewater, drinking water, surface water, cooling water, process water, etc., turbidity is an important commonly used and normative parameter. How is turbidity defined and how is it measured?

Turbidity is the degree to which light is scattered or absorbed within a liquid caused by the presence of undissolved particles. Simply explained, it is the degree of clarity of a liquid. When there are fewer undissolved particles in a liquid, the clarity increases, and the turbidity decreases inversely. With more undissolved particles in liquid, the clarity then decreases and the turbidity increases.

To measure the turbidity, an infrared light beam is sent into the liquid. Then, under a certain angle, it is measured how much scattered light is emitted from this light beam. This can be translated into the degree of turbidity of a liquid.

Over time, different units of turbidity have been developed and named after the measurement / calibration method or its inventor. Our measuring instruments use the NTU unit to measure turbidity.

The ideal turbidity for you depends on your personal application. We are happy to help you accurately and reliably measure and monitor the desired turbidity with one of our measuring instruments. View our range of turbidimeters here.