Which water type is not safe for human consumption?

Non-potable water is classified as water that is not safe for human consumption due to the presence of contaminants, pathogens, or hazardous substances that could cause illness. This type of water may come from sources that are not treated or tested for safety, such as untreated surface water, wastewater, or contaminated groundwater.

In contrast, distilled water is a purified form of water that has had impurities removed through the process of distillation. Potable water is specifically treated and regulated to meet health standards for human consumption, making it safe to drink. Rainwater can be collected and used for drinking if it is properly filtered and treated, although it typically requires testing and treatment before being deemed safe for consumption. Thus, non-potable water stands out as the type that should not be consumed due to its potential health risks.