Which of the following cannot be classified as graywater?

This option requires the project to classify water from toilets as blackwater, not graywater, because it contains human waste and pathogens that pose a health risk1. Graywater is defined as wastewater that contains fewer contaminants than blackwater, such as water from showers, sinks, and washing machines2. Graywater can be reused for non-potable purposes, such as irrigation and toilet flushing, after appropriate treatment3.