Why does well water become cloudy?

 Small solid particles that get into the water (suspension) can cloud the water. These are undissolved, inorganic minerals or organic particles. This can e.g. B. soil particles (erosion), but also microorganisms (algae, bacteria). As a rule, groundwater does not show any turbidity. There, cloudiness only occurs if, due to the change in chemistry (e.g. discharge of gases, change in pH value), dissolved ingredients flocculate.

In surface waters, cloudiness is often caused by algae growth. These have to be eliminated by appropriate treatment processes, as they can lead to recontamination on the one hand and can also cause odor and taste problems on the other. In the worst case, toxic cyanobacteria (blue-green algae) occur in eutrophied waters.

The monitoring of the turbidity is of great importance both for aesthetic reasons, but also due to the fact that the turbidity is an indicator of more serious contamination. Cloudy drinking water, which has its origin in surface waters, can also contain cryptosporidia and giardia, for example. Clouds of organic origin lead to growth and deposits in the pipe network and on fittings and thus to re-germination. In addition, there are smell and taste problems.