What is the recommended maximum leakage rate for this type of test?

• A. 240 gallons per inch O.D./mile/day of pipe
• B. 200 gallons per inch O.D./mile/day of pipe
• C. 260 gallons per inch O.D./mile/day of pipe
• D. 320 gallons per inch O.D./mile/day of pipe

Answer: (A)

This test uses a leakage allowance that scales with pipe size and length, measured in gallons per inch of outside diameter per mile per day. The value chosen as the maximum is 240 gallons per inch O.D./mile/day. This number represents a practical balance: it’s strict enough to catch meaningful leaks in joints and cracks without making it nearly impossible for longer or larger mains to pass.

If you used a smaller value, like 200, the test would be more stringent and could cause acceptable installations to fail. If you used larger values, such as 260 or 320, more leakage would be tolerated and potential leaks might be missed. For example, an 8-inch pipe over 5 miles would have a permissible leakage of 240 × 8 × 5 = 9,600 gallons per day.