Material List:

30 gallon plastic drum (make sure it is very clean)
"S-shaped" elbow for guttering
Pop rivets
Flat stones or patio blocks
Pump or spigot for barrel
Mosquito dunk

Tool List:

Hacksaw with at least 32 teeth per inch
Rivet gun
Garden spade
Drill

Steps to Build a Rain Barrel

Note: You will need to locate your rain barrel under an existing downspout.

1. Install a stone foundation. When your rain barrel is full, it will weigh an enormous amount. Therefore you must install a flat, level stone foundation to support the weight. Flat natural stones or prefabricated stepping stones will work for this purpose. Be sure the stones are secure and level.
2. Install your elbow. Place the barrel in the desired location. When you install your elbow, be sure not to cut off the downspout too high. Allow about a 2" overlap to connect the elbow and the existing downspout. Pre-drill your hole through both pieces and connect them using pop rivets.
3. Connect the elbow to the barrel. Most plastic barrels will have two holes in the top. If your barrel does not, you will have to cut at least one. Run the elbow into one of the holes on top of the barrel. After the rain barrel is complete, you may want to seal this connection tightly.
4. Install your pump or spigot. Next, install your pump. A barrel pump can be purchased for around $20 and will allow you to pump out water from the top (it is installed in the second hole). A spigot can also be installed near the bottom of the barrel by drilling a hole. A variety of spigots are available; check with your local home improvement store. If your barrel has no lid, you will need to drop a mosquito dunk into the barrel. Dunks are used in water gardens to prevent the presence of mosquitoes in standing water.
5. Install an overflow spout. An overflow spout can be placed near the top of the barrel. Simply drill a hole and insert a piece of plastic tubing. A hose may also be connected to this spout to water plants near the rain barrel.