A small windmill with direct mechanical drive to a water pump 
  is an  old  technology, and commercial  machines are still in 
  extensive  use  in  many  parts of the  world.  In most cases,  
  water is pumped  whenever the  wind  blows and is stored in a 
  tank for use as needed.  Careful  matching of the windmill to 
  pump  characteristics  is  important, and the  windmill, pump 
  and storage must be treated as a system.

  The conventional multibladed windmill is a type that has been 
  widely used for this  purpose in the past, but  has not found 
  widespread  application in  developing  countries  because of 
  economic and financial  reasons.  Compared to the traditional 
  multibladed  windmills,  they  are  considerably  lighter  in 
  weight,  more  simple  to construct and have slightly  higher 
  over-all  efficiency.  These  windmills,  after  adapting the 
  design to locally available materials, can be manufactured in 
  sparsely equipped workshops and are cheaper than commercially 
  available windmills by a factor of 2 to 4.Many such windmills 
  are  operating in pilot  projects in India,  Kenya,  Pakistan, 
  Peru, Tunisia and Sri Lanka. Experience in these projects are 
  showing  that  extensive  field  testing is essential, and is 
  resulting  in  several  design  modifications  to  ensure the 
  reliability of the machines. 

  Besides the design of all-metal  windmills, improved types of 
  sail and/or wooden windmills have been developed in  Colombia, 
  India and The Netherlands, to try and meet the demands of the 
  subsistence  farmer.  These mills, which can be fabricated in 
  village  workshops, are  cheaper than  commercial mills, even 
  allowing for replacement of sails every two years.  Drawbacks 
  of this type of windpumps are relatively low  efficiency and 
  higher time requirement for operation and maintenance.