Handy Manual: Not a do-it-yourself guide but to help you discuss this intelligently with the implementers

• Chapter 1 - Basics of rainwater harvesting
  
• Chapter 2 - Components of a rainwater harvesting system
• Chapter 3 - Catchment
• Chapter 4 - Gutters and Downtake Pipes
• Chapter 5 - Filters
• Chapter 6 - Storage tank
• Chapter 7 - Delivery systems
• Chapter 8 - Water quality and Precautions
• Chapter 9 - Maintenance of Rainwater Harvesting Systems