Did You Know? Collecting Rainwater for Your Garden

Collecting rainwater for your garden…it’s sounds pretty simple doesn’t it? Well, it can as simple or as complex as you make it with a little planning. One-third of all of the water used in the United States goes to irrigation. Now I don’t mean just the water that you use to water your lawn and garden; much of the irrigation water goes to agricultural production. And that’s important, right? Well, you could grow some of your own food to reduce your dependence on industrial agriculture but that’s not the topic of today’s post.

So how can you collect rainwater for your garden? There are all sorts of ways but let’s start with the simplest: the rain barrel. Rain barrels are an excellent way to capture some of the rainwater that is generated from your roof during a storm or shower. They’re scaleable as you can add bunches of them together so that you can keep collecting rainwater well beyond the typical 55 gallons that each holds. They can be attractive if you’re the artsy type…boy I wish was!

free water for your garden
Photo courtesy of www.prwd.org


So how much rainwater can a typical roof capture in a single rain storm? What’s your guess? 100 gallons? 1000 gallons? 10,000 gallons? Pull out your calculator (or your cell phone) and let’s do the math. My small rancher has a typical A-frame roof and each side of the roof is approximately 60′ x 20′. That’s 2400 square feet of roof surface area. Let’s say that we receive 1″ of rain. One inch of rain falling on one square foot of roof yields 0.6 gallons of water. So….2400 x 0.6 = 1440 gallons of rainwater. You would need 26 rain barrels just to catch the rain from a single 1″ rain event. In Virginia, we receive around 43″ of rainfall each year. That’s 61,920 gallons of water that you could be catching from your roof each year. That’s a lot of free water for your garden!

So what can you do if you don’t have enough room at your house for 1126 rain barrels (that’s how many you would need to collect all 61,920 gallons)? There are underground cisterns that can be installed to capture your roof runoff.

free water for your garden
Photo courtesy of www.chesapeakestormwater.net


These are systems that you need do some serious math for as well as figure out how you’re going to get all of that rainwater out of the tank. The beauty of rain barrels is that you use gravity to get the water out of the barrel and into your garden. With cistern based systems, you have to use a pump to get the water to your plants. But the cost of the water that is saved by capturing your roof runoff can more than offset the cost of operating the pump.

free water for your gardenWhat are some other ways to capture free rainwater for your garden if you don’t have access to an underground cistern? How about the tanks that everyone seems to have for sale these days? Check your local Craigslist for great deals. What about 5 gallon buckets to start with? Put one under each downspout to catch rainwater that you can use to water your garden. How about a kiddie pool? You can pick them up for under $10 at your local big box store. Any rainwater that you can catch is water that you don’t have to buy or pull from the depths of the ground to provide your plants with moisture.

What ideas have you used to capture rainwater for your garden? Leave me a comment below or e-mail me at stacey@midatlanticgardening.com. If you enjoy being part of the Mid-Atlantic Gardening community, join our e-mail list (upper right hand corner of this page), become a fan on Facebook and follow me at Twitter. Happy gardening!

May 14, 2012Permalink 3 Comments

3 thoughts on “Did You Know? Collecting Rainwater for Your Garden

  1. Pingback: Did You Know? Goldfish and Rain BarrelsMid-Atlantic Gardening

  2. We have a rain water collection system (gutters and rain barrels) for the barn. I use it to water the chickens and animals. We are building our house and I would LOVE to have a large cistern to collect the water. It doesn’t rain a lot in TX, but when it does, we get LOADS. I received 3.5 inches last week. It filled up the one barrel, and the majority flowed into our dry creek bed which funnels the water to our pond, so now our pond is full. I love using rainwater!

    • That’s great Amy! Have you all looked into a cistern since you’re building your house? Great work on the system that you’ve put together thus far!

Leave a Reply

Your email address will not be published. Required fields are marked *