With at least 20 percent of all people on earth not having enough water, rainwater collecting has been become popular in recent years as a way to provide clean, safe water to anyone with a roof. Once illegal in many towns and cities, today even more communities are now requiring all new construction to provide some way for the water that falls on it to be collected and re-used. Is this recycling something you could do at your own home?

First of all, let’s look at how this works.

The basic idea is simple: building owners channel the water that runs off their roofs into holding tanks for later re-use. Different filtering systems exist to make the water safe for any kind of use, and different-sized holding tanks—at a variety of prices—are now available so that the rainwater from even a short rainy season can provide enough drinking water and water for home use for the rest of the year. Pretty impressive stuff, and it doesn’t cost that much.

Before communities began to look at rainwater harvesting in recent years, the only way they could collect rainwater was to build expensive dams, canals or other catchment projects. Not only did these (radically) change the landscape, but they were costly and didn’t provide the cleanest possible water. And where communities couldn’t build dams or catch basins, they often turned to desalination plants. All of these are expensive, and none of them provide clean, dependable water all the time.

But now families are buying plastic 55-gallon barrels and getting started. Commercial building owners are building Olympic-swimming pool sized holding tanks. And home builders are burying tanks, hiding them behind landscape plants or plopping them right on the roofs of new buildings. All of these quickly pay for themselves.

What does it take to get started?

Not much. A clean roof is the first thing. Asbestos tiles don’t mix well with water recycling, and neither do copper roofs, but the cost of replacing a roof can quickly be recooped.

Gutters at the bottom of each slope on the roof come next, along with a downspout or piping of some sort to carry the water into the holding the tank.

Many kinds and sizes of water tanks work well with this. How much you want to spend and how much room you have for the tanks are two limiting factors. Keep the tanks covered (to keep out dust and debris) and keep direct sunlight off the water.

Basic filters are available (inexpensively) to purify the water as it goes into and out of the holding tank. This keep sediment and algae out and can also knock out harmful bacteria.

Finally, the wait for rain begins.

The technology for rainwater collecting is improving dramatically every year. It’s becoming less expensive and easier to find. The time may soon be ripe for you to take the plunge into harvesting water from your rooftop.