Which type of water is primarily handled by a drain?

The type of water primarily handled by a drain is wastewater. Wastewater encompasses any water that has been used and is no longer suitable for consumption or use without treatment. This includes water from sinks, toilets, showers, and industrial processes. Drains are specifically designed to remove this used water from buildings and carry it to wastewater treatment facilities, where it can be treated and possibly reused or safely discharged.

In contrast, potable water (safe for drinking) and fresh water (naturally occurring water that is low in salts) do not typically enter the drainage system as they are intended for consumption and usage. Storm water is also not primarily handled by standard drains; it is usually managed through separate stormwater systems designed to handle rainwater runoff, which can lead to issues like flooding and pollution if not properly managed. Thus, the focus on drains being utilized mainly for handling wastewater makes it the correct answer.