For apparatus with a water tank of 500 gallons or less, the required tank-to-pump flow rate is:

• A. Five hundred gpm
• B. Two hundred fifty gpm
• C. Two hundred gpm
• D. Three hundred fifty gpm

Answer: (B)

Tank-to-pump flow rate is the rate at which water is drawn from the apparatus water tank into the pump while the tank serves as the water source. The goal is to keep the pump fed without emptying the tank too quickly, which could cause the pump to starve for water or lose prime.

For tanks 500 gallons or less, the recommended rate is 250 gpm because it’s about half the tank’s capacity per minute. This provides a steady, sustainable transfer that maintains pump supply and leaves a reasonable buffer in the tank for continued operations or when you need to switch sources. Draining faster (for example, 500 gpm) would empty a small tank too quickly, risking suction issues, while slower rates (like 200 gpm or 350 gpm) don’t align with the standard guideline for this tank size and may under- or over-supply the pump relative to typical initial demands.