1) Limited and uncertain local
rainfall.
2) Can be costly to install – rainwater
storage and delivery systems can cost between $200 to $2,000+ depending on the
size and sophistication of the system.
3) The payback period varies depending
on the size of storage and complexity of the system .
4) Can take considerable amount of time
to “pay for itself” .
5) Requires some technical skills to
install and provide regular maintenance.
6) If not installed correctly, may
attract mosquitoes (i.e.; West Nile Disease and other waterborne illnesses) .
7) Certain roof types may seep
chemicals, pesticides, and other pollutants into the water that can harm the
plants.
8)
Rainwater
collected during the first rain season is generally not needed by plants until
the dry season. Once catchment is full, cannot take advantage of future rains.