How should you interpret a hydrostatic test result for a cold water installation?

• A. If the pressure is at or above the required level but leaks are present, the test passes.
• B. If the pressure holds for the required duration with no leaks, the test passes.
• C. If there are no leaks and the pressure holds for the specified duration, the test passes; if a drop occurs, repair leaks and retest.
• D. Hydrostatic tests do not relate to leaks.

Answer: (C)

A hydrostatic test checks a cold-water installation for leaks by pressurizing the system and watching how the pressure behaves over the test period. The important point is not just reaching the target pressure, but maintaining it for the specified duration without leaking. The best approach is to confirm there are no leaks and that the pressure remains stable for the entire test time. If the pressure falls at all, that indicates a leak or defect somewhere in the piping, joints, or fittings, so you must locate and repair the leaks and then retest until the pressure stays constant with no leaks. This ensures the system is truly watertight before it’s put into service. For a thorough test, also keep in mind that the system should be prepared correctly—isolated from the supply, free of air, and tested with appropriate equipment for the required pressure and duration.