What is the main risk if hydrants are opened too quickly?

• A. Water hammer and detect leaks or obstructions.
• B. Quick pressurization.
• C. Air entering the line.
• D. The water will be too cold.

Answer: (A)

Opening hydrants too quickly creates a sudden surge of water in the system, known as water hammer. That abrupt flow spikes pressure beyond normal levels, putting stress on pipes, joints, valves, and hydrants themselves. The resulting pressure transient can cause damage or leaks and can even reveal weak points by pushing water through small openings or obstructions. Slower opening reduces the surge, protecting the distribution system and equipment.