Natural water will contain suspended matter which includes hard particles (sand, rock, silt and pipework debris), soft particles (vegetal debris) and colloidal particles (organic or inorganic).
Suspended Particles

Suspended particulates are microscopic solid or liquid matter suspended in the Earth's atmosphere.

The term aerosol commonly refers to the particulate/air mixture, as opposed to the particulate matter alone.

Major sources of primary particles are industrial processes, road traffic, power plants, domestic burning incineration, and resuspension of road and construction dust. Particulate matter is removed from the atmosphere by wet and dry deposition.

Impact on your systems

Suspended particles can foul reverse osmosis membranes and interfere with the operation of valves and meters. Fine-bore analytical columns can be blocked by suspended particles, while instrument operation can be impacted thanks to water turbidity caused by colloidal particulates.