Book excerpt: This work introduces the principles of water hydraulics technology and its benefits and limitations, and clarifies the essential differences between water and oil hydraulics. It discusses basic components and systems, including hydraulic power generators (pumps), hydraulic control components or modulators (valves), hydraulic transmission lines (tubes, hoses and fittings) and hydraulic actuators (single- or double-acting cylinders and rotary motors). A listing of water hydraulics components/systems manufacturers is provided.