What is the typical discharge rate of a sprinkler head at 30 psi?

• A. 60 GPM (@ 60 psi)
• B. 30 GPM (@ 30 psi)
• C. 15 GPM (@ 25 psi)
• D. 40 GPM (@ 30 psi)

Answer: (B)

Discharge from a sprinkler head depends on the opening size (orifice) and the pressure across it, and standard heads are designed so that, around 30 psi, they deliver about 30 gallons per minute. This gives a convenient rule of thumb: at 30 psi, a typical head flows near 30 gpm, which is why that option matches common performance data used in quick calculations.

Remember the flow doesn’t jump linearly with pressure — it increases roughly with the square root of pressure. So at 60 psi, you wouldn’t expect 60 gpm from the same head; it would be closer to about 42 gpm. The other options imply either a much larger or smaller head than is typical for standard installations at that pressure, so they don’t fit the common performance of a standard sprinkler head.