Booster Pump Creating Cross-connection Incident (Case 1)

The booster pump to a building provides water to the top floor of the building. The booster pump is needed because the public water system pressure at times does not have sufficient pressure to provide water to the top floor of the building. At times when the water pressure in the main is low and the booster pump is activated a negative pressure is created in the water main, which created a pressure loss situation in the adjacent buildings. If there are unprotected cross-connections such as submerged inlets in the adjacent buildings a siphon effect is created when the water in the adjacent building is used on a level lower than the submerged inlet.  A cross-connection incident was created by the activation of the fire pump and non-potable water is entering the potable water system.   Internal protection and low-pressure cut-off switch would prevent this situation from occurring.