To collect rain water, you need to select rain barrels made for rain capture.
Should be easy to install with a modular design to expand capacity by simply linking multiple barrels
Barrels should be at least 6 inches above ground for gravity discharge via a garden hose or to allow filling a bucket
Barrels stand can be made out of 2 2x6 pressure treated lumber custom cut to size sitting on concrete blocks. The stand should be level for the overflow to work properly.
Barrel spigot should be bronze not plastic
Barrel top/cover should be easy to open for cleaning
Barrel filter should be easy to clean and prevents mosquitoes from going in
Install overflow hose to divert excess water to a diverter away from the foundation
A good rain can fill three barrels connected to each other in two days
Some Water Districts offer rebates. You need to submit an application before you start your project for approval.
Lastly, you will have fresh rain water to use in your garden during the summer and you save on water bill.