Water pumping windmills Backwoods Home Magazine
This larger windmill will pump an annual average of 4500 gallons per day, or million gallons of water a year. This figure is based on moderate winds (812mph) blowing part of the time, running the mill at half its rated capacity, and brisk winds (15 to 25 mph) blowing about 30 percent of the year and running the pump at maximum capacity.