Rainwater harvesting systems do not have to be expensive or complicated. It is easy to get started with rain barrels and expand later. In fact, it is better to start with expansion in mind. As your budget and/or the cost of water increases, it is then easy to add on.  Rainwater harvesting systems have 4 major and very different subsystems:

1) Capture
2) Conveyance
3) Holding
4) Distribution