Hydraulic Pumps are commonly used in liquid transfer & spraying operations. These pumps are driven by a hydraulic motor mounted directly to the sprayer or transfer pump. The most common are hydraulic-drive centrifugal sprayer pumps from Ace and Hypro. Another popular version are hydraulic-driven centrifugal transfer pumps from MP Flomax, Hypro, Pacer & Banjo Pumps. There are also hydraulic-drive gear pumps from Hypro.

Advantages of hydraulic-driven pumps include the ability to provide high pressures for spraying (over 100 PSI), the ability to work well in hot or cold temperatures and no need for gas or diesel engines that require repeated fueling & maintenance. Hydraulic-drive centrifugal pumps and gear pumps are also economical relative to engine-drive pumps, especially in the larger sizes.

Hydraulic driven pumps are fed hydraulic oil from a hydraulic pump (usually from the truck or tractor's hydraulic system) through a high pressure supply hose (generally 2,000 to 3,000 PSI) to the hydraulic motor on these pumps. A "return" hose is also run back from the hydraulic motor to the hydraulic reservoir on the truck or tractor. It is important not to over-speed the hydraulic motor on these types of pumps. This is caused by supplying hydraulic oil at too high of flowrate to the hydraulic motor and can damage to the motor and pump bearings & seals. The best approach for preventing overspeeding of a hydraulic-drive pump is to match the flowrate of the motor on the pump to the flowrate of the hydraulic system on the truck or tractor. Many hydraulic-drive pump manufacturer's provide two or three different hydraulic motors for a particular pump for this purpose. A flow limiting valve can help prevent over-speeding of the hydraulic motor by limiting the oil flowrate into the motor.