Which hose diameter is used for both supply and attack lines?

• A. 1 inch
• B. 3 inches
• C. 2 1/2 inches
• D. 4 inches

Answer: (C)

The main idea is the balance between flow and handling. A two-and-a-half inch hose hits that sweet spot: it can deliver a solid, practical flow for an attack line with common nozzles, while still being light enough and flexible to use for supply duties when needed. This size is a standard for rapid deployment pre-connects and is commonly adapted for supply runs between the hydrant, pump, and equipment, making it versatile for both roles.

Smaller hoses, like a one-inch line, can’t provide enough water quickly enough for many interior fires. Larger hoses, such as three or four inches, carry more water but are harder to maneuver and usually aren’t the preferred choice for an attack line. So the two-and-a-half inch option best fits the need for both supply and attack purposes.