Under what condition should a fire hydrant be installed at the end of a dead-end main?

• A. If the dead end main is at least 6 inches in diameter and has sufficient pressure and flow
• B. If the main is 8 inches and can meet any pressure
• C. Only if the main serves a building
• D. Only if the main is newly installed

Answer: (A)

Place a fire hydrant at the end of a dead-end main only when the distribution line can actually support it without compromising service or firefighting capability. The line must be at least 6 inches in diameter and have enough pressure and flow to meet firefighting needs and to allow flushing at the dead end. This ensures the hydrant will deliver adequate water without causing excessive pressure loss elsewhere in the system. If the main is smaller than 6 inches or cannot provide sufficient pressure and flow, adding a hydrant could be ineffective or harmful. The decision isn’t about whether the main serves a building or whether it’s newly installed; those factors don’t determine the suitability of placing a hydrant.