What is the required depth to submerge the barrel strainer below the water surface when testing from a static source?

• A. 3 feet
• B. 1 foot
• C. 2 feet
• D. 4 feet

Answer: (C)

When testing from a static water source, the barrel strainer must be kept under water enough to stay submerged and maintain a stable water supply to the pump. Submerging it two feet below the surface provides enough hydrostatic pressure to prevent air from entering the suction line and to keep priming reliable, without adding unnecessary depth that would complicate the test or increase the head the pump has to overcome. If it’s only nearer the surface, air pockets can form and prime can be lost; going deeper than two feet isn’t required for this test and isn’t typically specified. So the required depth is two feet.