First, you need a surface. Your roof is perfect. Gutters are your best friends. Direct the water into a barrel or a food-grade container.
Pro tip: don’t use a rusty old oil drum. That’s a disaster. You want something clean, like a blue plastic barrel or a fancy store-bought rain tank.
Make sure the barrel has a screen on top. This keeps out leaves, frogs, and the occasional curious squirrel. Frogs don’t like being filtered.
Fun Fact:
A single inch of rain on a 1,000-square-foot roof gives you about 600 gallons of water. That’s enough to fill a hot tub. Or water a garden for a month. Or have a very wet party.
Rainwater Filter Methods at Harry Oloughlin blog
