Apparatus equipped with water tanks of 500 gallons or less must provide a tank-to-pump flow rate of blank GPMs; those with tank larger than 500 gallons must provide blank GPMs.

• A. 250, 500
• B. 125, 250
• C. 300, 600
• D. 200, 400

Answer: (A)

Tank-to-pump flow rate is about how much water the pump must be able to deliver from the apparatus’s own tank to the hose line while you establish a supply. The standard sets two minimums: 250 GPM for tanks 500 gallons or less, and 500 GPM for tanks larger than 500 gallons. This scaling makes practical sense: a smaller tank can only furnish a modest flow, so a lower but still useful rate (250 GPM) ensures you can attack effectively without exhausting the tank immediately. A larger tank can provide more water, so a higher discharge (500 GPM) is appropriate to deliver a strong stream and keep a usable flow as the water source is developed. The other pairings would either demand too much from a small tank or underutilize a large tank, which is why they aren’t used.