What can result from inadequate water treatment?

Inadequate water treatment can lead to the presence of harmful contaminants in the water supply, which significantly increases the risk of waterborne diseases. These diseases are caused by pathogens such as bacteria, viruses, and parasites that can proliferate when proper disinfection and filtration processes are not employed. Without effective treatment, these microorganisms can contaminate drinking water, posing serious health risks to consumers, including gastrointestinal illnesses, cholera, and typhoid fever.

The other options, while important aspects of water quality, do not directly correlate with the consequences of inadequate treatment. Increased clarity of water, reduction of mineral content, and improved taste typically indicate effective treatment processes, rather than results of insufficient treatment. Thus, the presence of waterborne diseases is the most critical and direct outcome of inadequate water treatment.