What must be airtight and able to control both intake and discharge lines?

Valves are crucial components in a mobile water supply system because they need to create an airtight seal to effectively manage the flow of water. When both intake and discharge lines need to be operated, valves ensure that water can be controlled precisely, preventing leaks and maintaining pressure within the system.

Airtight functionality is vital in preventing contamination, maintaining water quality, and ensuring operational efficiency. When the intake line is opened to draw water, the valve needs to close off the discharge line to avoid backflow and potential mixing with contaminated water. Similarly, during discharge, a valve controls the flow out to the system while keeping the intake line closed to secure the quality of any incoming water.

Filters, while important for removing impurities, do not require airtight functionality in the same manner, as their purpose is not to control flow actively. Pumps are designed to move water rather than to regulate its flow through sealing mechanisms. Hoses, although they transport water, cannot control flow or pressure on their own without the help of valves. Therefore, the specific requirement for airtight control directly points to the role of valves in this context.