What is turbidity and how much is acceptable in drinking water?

Turbidity is the cloudy appearance of water caused by  the presence of suspended matter. If present at high levels, turbidity can provide an environment which shields pathogens from disinfection. The Australian Drinking Water Guidelines specify an aesthetic guideline of

5NTU (Nephelometric turbidity units) or, if disinfection is undertaken, less than 1NTU. In 2016-17, Busselton Water recorded a maximum of 0.6 NTU for its water samples.