Which of the following is a common component of water supply systems?

A hydrant system is a critical component of water supply systems used in fire protection. These systems are essential because they provide a readily accessible water source for firefighters during emergencies. Hydrants are strategically placed throughout communities and are connected to municipal water mains, ensuring a quick and reliable water supply needed to extinguish fires.

Hydrant systems are specifically designed for fire response, allowing firefighters to connect hoses directly to the hydrant, thereby facilitating a rapid deployment of water to the scene of a fire. This system is engineered to deliver high volumes of water quickly, which can be crucial in controlling and extinguishing fires efficiently.

The other options represent important tools or systems in various contexts but do not typically function as primary components for water supply in fire service operations. For instance, tankers may transport water but are not fixed systems like hydrants. Manually operated pumps can be used in certain situations but do not serve the same widespread, integrated purpose as hydrant systems. Chemical spray units are often related to specific types of firefighting, particularly in hazardous materials incidents, and are not a common component of standard water supply systems.