Ground water supply systems are required to maintain a minimum water pressure of what psi during emergency conditions?

The minimum water pressure requirement of 20 psi during emergency conditions in groundwater supply systems ensures that adequate pressure is maintained for basic water service demands such as fire protection, sanitation, and, to a certain extent, public health. This pressure level allows for water to adequately flow from faucets and other outlets, ensuring that essential services are available even during emergencies, such as a disruption in the system or an unexpected drop in pressure.

While there are higher pressures specified in some contexts, the choice of 20 psi is a standard minimum that reflects the balance between maintaining essential service and the practicality of system operation. A pressure lower than this could lead to insufficient water delivery, which can have serious ramifications in emergencies. Therefore, setting this threshold is key to ensuring the reliability and safety of water supply systems under duress.