A windmill is one of the most energy efficient and ingenious ways ever devised to pump water from the ground. A windmill harnesses the free and renewable power of the wind and uses that energy to lift underground water to the surface for agricultural and other uses.

Because windmills are so efficient and durable, the basic design hasn't changed in almost 120 years. The secret lies in the way a windmill harnesses the wind's energy to power a n ingenious water pump located deep underground.

The power of the wind is captured and harnessed in two steps. Each step is easy to identify by simply observing a windmill in action.

First, the fan turns. A windmill captures the energy of the wind with the large, circular fan, or "wheel", located at the top of the tower. When the wind blows, the fan rotates. This turning (rotary) motion is so commonplace that it's easily taken for granted. But don't. This is where the free energy of the wind is captured.

Second, look just below the windmill's wheel and notice a long rod extending from the motor to the well cylinder deep in the well. This combination of “ pump rod”, “pump pole” & "sucker rod", is powered by the windmill's motor. This motor is a unique set of mechanical gears that converts the rotary motion of the wheel into a reciprocating (up and down) motion that powers the cylinder pump located deep underground.

Water trapped in an underground, water-bearing formation is called an aquifer. The top of an aquifer is called the "water table". The depth of this water table is important because it determines how deep a water well must be drilled. It also determines the size of the windmill required to pump water to the surface.

A water well is a small-diameter hole drilled into the earth's crust that fills up with water. As the well is drilled, it passes through various underground layers of sand and gravel, and extends into an aquifer, or underground water-bearing formation.

Once the well is drilled to the proper depth, the well wall is reinforced and perforated to allow water from the surrounding aquifer to seep into the well. Gravity causes the water to rise to the level of the underground water table.

A sealed "drop pipe" is then inserted into the well until its lower end is fully immersed in the well water.

The cylinder pump, or well cylinder operates in a very ingenious way. It doesn't use high-powered suction. Instead, it builds a "column of water" from the aquifer to the surface within the drop pipe... from the bottom upward.

The cylinder pump accomplishes this feat by creating a one-way flow of water within the drop pipe and constantly ratcheting water upward.

Two specialized pump valves work together to draw well water into the bottom of the drop pipe and then ratchet the water column upward. By repeatedly adding water to the bottom of the water column, the drop pipe fills and water pours out the top into a storage tank.