What is the minimum allowable pressure in a water distribution system during emergency conditions?

In a water distribution system, maintaining adequate pressure is crucial for ensuring a reliable supply, especially during emergency conditions. The minimum allowable pressure during such scenarios is set to ensure that consumers have enough water supplied for domestic use, firefighting, and maintaining adequate water quality.

A pressure of 20 psi is significant because it generally represents the minimum threshold necessary for most residential uses, such as functioning faucets, showers, and other fixtures. This level of pressure helps prevent issues related to backflow and ensures that water can effectively reach consumers, allowing for emergency services like firefighting to operate properly.

In contexts where lower pressures are permitted, you might encounter problems with adequate service delivery and water quality, such as reduced flow rates and potential contamination risks due to lack of pressure. Therefore, 20 psi is established as a practical and safe minimum that protects public health and safety in emergency situations.