A rain barrel captures roof runoff from a downspout to water your garden, saving treated water and reducing storm runoff. It's a simple, satisfying setup with a few details that make it work well.
Set it up
Place the barrel on a stable, raised base under a downspout — raising it gives gravity pressure for a hose or watering can, and a level base keeps a full barrel (which is heavy) from tipping. Cut the downspout and add a diverter so it fills the barrel and bypasses to the original drain when full.
Manage overflow
A barrel fills fast in a real rain, so an overflow outlet must carry excess water well away from the foundation — defeating the purpose if it dumps at the wall. Connect overflow to a hose, splash block, or a second barrel.
Keep it clean
Screen the inlet to keep out debris and mosquitoes — standing water breeds them. Use the water on gardens and lawns rather than for drinking, since roof runoff isn't potable. Drain and disconnect before winter freeze.