What maximum pressure is allowed in a water distribution system before a pressure reducing valve is required?

• A. 85 psi
• B. 60 psi
• C. 80 psi
• D. 45 psi

Answer: (C)

Maintaining safe water pressure is essential to protect pipes and irrigation components. Codes typically require a pressure reducing valve once supply pressure reaches about 80 psi, to bring the downstream pressure down to a safer range for sprinklers, valves, backflow preventers, and controllers. High pressure can cause leaks, pipe or fitting failure, water hammer, and erratic sprinkler performance. Downstream pressure is usually kept around 40–60 psi, which keeps equipment operating reliably without overloading it. So, 80 psi is the maximum before a PRV is needed; above that, a valve should be installed to reduce the pressure.