Which of the following is the minimum diameter for mains to accommodate standard pumper-connection hydrants?

• A. 8 Inch
• B. 6 Inch
• C. 4 Inch
• D. 10 Inch

Answer: (B)

The main idea here is that water mains must be large enough to feed hydrants that a pumper uses to take on a big supply of water. Standard pumper connections are designed to draw significant flow, and a 6-inch main is the smallest size that can provide that volume without causing excessive friction losses and pressure drops. A 4-inch main would restrict flow too much for reliable pump operations, while 8-inch or 10-inch mains would work but exceed the minimum requirement. Therefore, 6 inches is the minimum diameter that accommodates standard pumper-connection hydrants.