Is the water clean?  
  How much water is saved?  
  Why should I buy one?  
  What can I use the water for?  
  How much does it cost to run the pump?  
  How big is the system/storage tank?  
  Do Building Regulations affect/require the installation of a system?  
  What maintenance is required?  
  How old is the technology?  
  Can I get any grants or tax allowances for installing a system?  
  Is it a proven technology?