In the forums, robblat asked about rain barrels: Are they useful? How much do they cost? Where do you get one? My wife just installed a rain barrel last year, so I asked her to explain how they work.

For my birthday last year, I asked my parents for a rain barrel. After doing some research online, I went to our local nursery and paid $100 for a complete barrel set up. While it will mean a small savings on our future water bills, the upfront cost is really too high to justify it from a purely financial standpoint. Instead, I wanted to collect rainwater for several other reasons.

Collecting a renewable resource for our own use
Rainwater belongs to everyone, right? But for the most part, we are dependent on a vast infrastructure to collect, purify and deliver this most basic of life’s requirements to our doors (er, faucets). I like the idea of harnessing a bit of that rain before it makes it through the whole human system. My plants don’t need chlorinated water, anyway! Plus, anecdotal evidence on gardening websites suggests that plants do better with lukewarm rainwater than cold tap water.

Minimal money savings
If you are serious about reducing your irrigation water use from the municipal water supply (and thus your bills), you can rig up a system of multiple rain barrels. One or more is attached to the house’s downspout; the rest of the barrels are linked to the first ones to collect their overflow when it’s really raining.

Get this: if you have 1,000 square feet of roof surface area, then one inch of rainfall will produce over 600 gallons of rainwater. How big is your roof? I have my rain barrel hooked up to our detached garage (an old carriage house), and its roof is about 300 square feet. If you cut that in half (I’m only getting the rain from half the roof) and do the math, my 60-gallon rain barrel will be filled by just two-thirds of an inch of rainfall. In Oregon, that’s easy! The overflow drains through a tube that I have draped under the boxwood hedge, or I could collect it in a secondary container.

Convenience
Our 3/5-acre lot has a grand total of one outside spigot, right by the house. Watering the far reaches of the gardens (vegetable, fruit, and flower) requires lugging hoses across the lawn and around trees. With the rain barrel at the garage, I can easily fill a watering can or bucket for the flower beds for some quick spot watering. While the gravity-fed flow of the rain barrel isn’t typically enough pressure to power a sprinkler, it would be enough for a short soaker hose. A rain barrel by the patio would be ideal for watering potted flowers and container plants near the house.

A few more considerations
Rain barrels come in many sizes and designs. Some are made to be pretty; others, not so much. Some are made from recycled or reused materials. A few have a flat side so they can sit flush against the wall, or have built-in storage for hoses and such. There’s plenty to choose from, but this is a bulky item, so avoid shipping costs and find a local store that stocks them. You may think a big plastic barrel isn’t your idea of garden décor, but what’s more fashionable than not wasting water?

You can certainly make your own if you are handy and have a source for a large food-grade barrel. It must be food grade so you aren’t having plastics leach into the water that you’re using to water your carrots. And be sure to have a screen to close it off. This will prevent mosquitoes from breeding in the barrel and keep leaves, mischievous animals, and small meteorites out.

Like any irrigation supply dependent on rainfall, sometimes you’ll have too much and sometimes not enough. July, August and September are pretty dry here (I kid you not), so my barrel did run dry last summer. But it doesn’t take much rain to fill it back up. I tend to do most of my flower garden-watering in the spring when I’ve just planted seeds and seedlings and they’re not fully established yet. The rain barrel is perfect for those dry, beautiful 75-degree days between our Spring rainstorms.

Watch the overflow location: you may need to extend the overflow hose to prevent drainage near your home’s foundation. Portland actually gives residents a one-time credit if the house gutters are disconnected from the storm sewer system. Rain barrels have been popping up like wild flowers in certain neighborhoods!

Today rain barrels — maybe in a decade or two, solar panels so we can go off the grid?