Gutter to Garden in 4 Easy Steps

Reader Contribution by Ann Nguyen and The Ecology Center
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Before we had concrete, storm drains, and rain gutters, our diverse habitat naturally carried and captured rainwater via streams and rivers and filtered the water in wetlands. In contrast, in today’s urban developments, rainwater flows down driveways and streets, contributing to flooding, erosion, and landslides. Runoffs also collect pollutants from our cars and fertilizers as it travels to the ocean and pollute the environment. 

Fortunately, there are a variety of simple and easy ways that we can re-design our spaces to follow nature’s model! 

Calculate Your Rainwater Harvesting Potential

Harvesting the rain with a barrel is a simple way to recycle water. Before you get started collecting rainwater, calculate your catchment to determine just how much water your property can collect and how much.

By harvesting the rain, we can collect every drop and grow healthy gardens instead of letting it run-off to pollute our watersheds and ocean. Here in Southern California, we get about 15 inches of rain/year. It might not be much, but it adds up quickly. In fact, the average Southern California rooftop could collect almost 1,000 gallons of water with just 1″ of rainfall!

Follow the instructions below to calculate your catchment so you’d know the rain barrel size you’d need to obtain or build!


1. Using your tape measure or string, measure the width and length of your home, classroom, office, chicken coop etc. Any structure with a roof can harvest the rain!

2. Calculate the square footage (width x length [floor in feet] = catchment area [square feet])

3. Awesome! Let’s assume the square footage is equal to it’s roof. Now you can estimate how much rainwater you could collect.

4. Harvested Water (Gal) = Catchment Area (sqft) x Rainfall Depth (inch) x Conversion Factor (0.623)

5. For example, let’s say your square footage is 3,000 sq. ft. (the size of the average Southern California home), and it rains 1 inch.

6. 3,000 sq ft x 1″ x 0.623 = 1,869

7. That’s 1,869 gallons of water that we could potentially divert from the drain and into our garden.

Make a Stand for Your Rain Barrel

Proper placement of your barrel is important. It ensures that you maximize your barrel in terms of both aesthetics and function. For some of you, determining where to position your barrel will be easy, for example, if you have only one downspout, or very limited free space in your yard. For others, the options on where to place your barrel could seem infinite. Follow the instructions below to determine where to place your rain barrel and how to build a stand.


1. Choose a downspout – Explore the outside of your home to determine where, if any, the downspout(s) is located. Larger homes and apartment complexes will typically have more than one.

Once located, there are a few questions to ask before you choose which downspout to place your barrel underneath: What is the potential harvest off this particular section of roof? This is easy to determine using the formula above. How easy will it be access your barrel? Is it near or far to the garden? Is it blocking a walkway that people or trashcans regularly move through?

2. Build the foundation – Once you’ve chosen a downspout, you’re ready to build the foundation for your barrel. Make sure the ground is solid and level. If the area is concrete or asphalt, you should be good to go! If it’s comprised of dirt, consider using bricks, pavers, tiles, broken concrete, or whatever you have to provide a solid base. If you place your barrel onto bare dirt, it could shift and become unstable when it rains.

3. Make a stand – Now, you need a stand. Why a stand? The purpose of a stand is two parts. One, is to provide easy access for a watering can, or hose, to the barrel spigot. Two, is to lift the barrel off the ground just enough in order to use the force of gravity for water pressure. The last thing you want is a barrel, full of rain water, with no way to access it! Use what you have to make a stand. Get creative! Stack cinder blocks or bricks, or build a simple wooden stand. If building your own stand, keep in mind the weight of a full barrel (example: 55 gallons at 8 pounds/gallon = 440 pounds plus a few). You can build a simple bench seat with a few nails and 4×4‘s boards.

4. Install – Now that your barrel is beneath a downspout and above solid ground, you’re ready to install. Follow the instructions below if you need some installation tips. Consider securing the rain barrel to your home. 440 pounds of water could easily fall and injure someone or something during an earthquake. If this is a concern, use a tie-down strap or rope to secure it to your home.

How to Install a Rain Barrel

With a rain barrel, you can capture that rain and reuse it to feed plants with nutrient-dense water, save money on your water bill, and reduce harmful urban run-off that would otherwise pollute our watershed and ocean. Installing a rain barrel is easy. Here’s how:

Materials and Tools

Rain barrel (you can use a variety of water-tight containers or sealed drums). We recommend food-grade, BPA free, drum grade HDPE resin, such as this 55-gallon rain barrel.
Measuring tape, pencil, beam level, electric drill, Phillips screwdriver or drill bit, material for solid surface base, rain barrel installation kit (includes hole saws [2 1/8” & 1 1/2” & 1”] spigot and gasket, diverter, fill hose, winter hole cover, water seals and screws)


1. Select a site for your new barrel—close to a downspout, near the desired area of use, and on a solid surface.

2. Build a level platform for your rain barrel before beginning the installation process. The platform will allow your barrel to fully drain using gravity. Try using cinder blocks, bricks, or wood blocks. Ideal height will be 18”-32”, based on your needs.

3. On the barrel, measure 2” down from the top and drill a hole using 1 1/2” hole saw. Insert gasket. This is where your barrel will connect to the downspout.

4. Measure 2-4” from the bottom of the barrel. Drill a hole using 1” hole saw. Insert gasket and screw in spigot. This is where you will connect your hose to water your garden. Empty barrel of plastic shavings left behind from hole saws.

5. Position barrel. Use the beam level and pencil to mark a reference line on the downspout, at the height of the barrel, then measure 2” below that. Here, drill a hole in your downspout with the 2 1/8” hole saw. Note: Make sure the hole in your downspout is level with (or slightly below) the hole in your barrel.

6. Connect fill hose to diverter. Insert diverter into downspout hole, funnel facing up, and tighten with the 2 screws provided.

7. Connect opposite end of fill hose to barrel. Cover with the lid and lock into place.


Many cities, counties, water districts, and conservation agencies offer rain barrel rebates and incentives for rainwater harvesting. Be sure to check with your local jurisdiction or water district for how to apply.

How to Connect More than One Rain Barrel

Materials and Tools

• Two or more rain barrels
Rain barrel diverter & parts kit
• Power drill
• Pencil
• Female garden hose end or male-to-female hose adaptor


1. When connecting two or more barrels, ensure you have sufficient, sturdy, and level space. This is important, especially if you want your barrels to act as a single unit, then they must be level.

2. Measure 2” from the bottom on each barrel. Mark with a line. Using the hole saw, drill a hole using the 1.5” hole saw at the line. Insert threaded seal into hole.

3. Position the second barrel adjacent to the first and attach hose to bottom drain on first barrel. Connect other end of hose to the bottom of second barrel.

4. Viola! As your first barrel fills, the second barrel will fill at the same level.

If you notice that your rain barrel’s still over full, remember to direct your overflow back into your garden or to a pervious surface (and not out the driveway). Follow nature’s model and always Slow It, Spread It, Sink It!

All photos by Scott Sporleder

Ann Nguyen joined the educational nonprofit The Ecology Center in Spring 2014, where she manages the marketing and PR teams, facilitates online content, creates and implements marketing campaigns, manages social media channels, markets events and workshops, and produces the center’s quarterly sustainability journal, Evolve. She holds a certificate in permaculture design.Click hereto read all of Ann’s MOTHER EARTH NEWS posts.

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