A pressure washer system includes an internal combustion engine and a water pump. The internal combustion engine includes an engine block forming a chamber and a cover for the chamber. The cover has an area designed to hold a lubricant. Additionally, the engine includes a crankshaft within the chamber. The water pump includes a pumping mechanism, an inlet, an outlet, and a fluid passage. The pumping mechanism is powered by the crankshaft. Water enters the pump through the inlet and exits the pump through the outlet. The fluid passage extends between the inlet and the outlet. A portion of the fluid passage is formed in the cover of the engine. Heat transfers from the lubricant of the engine to the water of the water pump during operation of the pressure washer system.