Location

• Although rainwater seems to be an all-natural addition to the garden, its safety depends on the location of the rain barrel. Some rain barrels sit at the corners of buildings and catch water running off the roof. Other rain barrels sit in open space and catch water directly from the sky or from trees overhead.
  
  

Safety

• Rainwater that comes off a roof may contain an array of harmful chemicals and should never go into the vegetable garden. Rainwater collected from a barrel in an open area or one that sits under trees, is safe for vegetable gardens.
  
  

Vegetables vs. Flowers

• Rainwater collected from roof runoff may be safe for gardens that contain only non-edible plants like trees and flowers. Chemicals from the roof may get into edible fruits and vegetables and pass on to the people that eat them, while they won't pass on if used in decorative gardens.