How often are flow tests on underground mains required?

• A. Annually
• B. Every three years
• C. Every 5 years
• D. When underground piping is repaired

Answer: (C)

Flow tests on underground mains are used to verify that the water supply can deliver the required flow and maintain pressure for the system, even as the piping ages or some capacity is lost to sediment, valve leakage, or minor damage. Because underground mains are buried and changes in their capacity occur gradually, testing is scheduled on a five-year cycle rather than annually or every few years. This interval balances the need to confirm adequate supply with the practicality and cost of testing. After major repairs to underground piping, a test is performed to confirm the repair, but the routine interval for testing remains five years.