What happens when the potable water pressure is lower than the wastewater pressure?

When the potable water pressure is lower than the wastewater pressure, back siphoning occurs. This condition poses a significant risk to safe water supply, as it can cause contaminated water to be drawn back into the potable water system. Back siphoning happens due to a difference in pressure, where the higher pressure from the wastewater system can force water into the drinking water source if a pipe breaks or if there is a drop in the drinking water pressure, potentially leading to harmful contaminants entering the potable water supply.

Understanding this principle is crucial for implementing proper preventative measures, such as cross-connection control and installing backflow preventers to ensure water safety. This emphasizes the need for maintaining adequate pressure in the potable water system to protect it from potential contamination.