An approved pressure-reducing valve must be installed when the street pressure exceeds what value?

The correct answer is based on established plumbing codes and standards regarding the installation of pressure-reducing valves. When the street pressure exceeds 80 pounds per square inch (psi), it is generally required to install a pressure-reducing valve to prevent potential damage to plumbing fixtures, piping, and appliances due to excessive pressure.

Operating plumbing systems at pressures higher than the recommended levels can lead to issues such as leaks, ruptured pipes, and failure of fixtures. Thus, maintaining a controlled and safe water pressure is essential for the longevity and efficiency of the plumbing system. The choice of 80 psi is significant because it has been recognized in the plumbing industry as a threshold at which pressure-reducing valves become necessary to protect both the integrity of the plumbing system and the safety of the household.