One Rain Barrel or Many? Single vs. Multi-Rain Barrel Systems

As a company specializing in multi-barrel rainwater catchment systems, we often get asked: Why can’t I order just one barrel in my rain barrel system? 

The short answer is, you can. But it's a different setup, and therefore a different ordering process. This article covers the pros and cons of single rain barrels vs. connected rain barrel systems, and how to order the right solution for you. 

The BlueBarrel Rainwater Catchment System™

Multi-Barrel Rain Catchment Systems

The BlueBarrel Rainwater Catchment System™ is our trademarked, flagship design—the one we're famous for! It is a modular, multi-barrel rain catchment system made from repurposed 55-gallon barrels. The system is plumbed together from underneath using our custom-packed DIY RainKits™, creating one large-capacity storage unit out of separate barrels.

With this uniquely advantageous design, all barrels in the system fill and empty simultaneously. This means the entire system only needs one downspout connection and one outlet (though you can customize with extras of both).

Because the underplumbing is a linking mechanism, the minimum size for taking advantage of the benefits of this design is two barrels. The the maximum size is, well, unlimited.

Our DIY RainKits are versatile and customizable. Users can customize kits for up to four systems at a time, with up to 30 barrels per system in our interactive online store. You can also choose from three downspout diverter sizes, or no diverter. You can start with a couple barrels and order an Add-On Kit later. Customize further from our accessories menu on the way to checkout. We include easy-to-follow, photo-illustrated instructions, and we have step-by-step how-to videos just for our RainKit customers.

Visit our Online Store and select one of the RainKit™ options if you want a complete, multi-barrel system!

Single Rain Barrels

For those who simply want a single rain barrel, we carry the DIY Rain Barrel Kit - Single.

Because this is a pre-packaged product and not user-customized, it is available on our Accessories Menu.

This off-the-shelf kit can be used to turn just about any barrel into a rain barrel. It includes a downspout diverter, and  spigot and drain valves that are installed directly into the barrel (rather than as part of BlueBarrel's bottom-draining, underplumbed design). It also includes all necessary installation tools and instructions. 

Pros and Cons

We are partial to our multi-barrel set-up. And not just because it can hold more water. The system is totally modular, flexible, and portable (when empty). Since it’s plumbed underneath, you can drain every inch of capacity—no pesky water festering in the bottom of your barrels at the end of the irrigation season! For a more detailed list of benefits, please view our About The BlueBarrel System™ page

Here is a quick visual comparison of the features and benefits benefits of single rain barrels vs. BlueBarrel's multi-barrel rain catchment systems.

Single vs Multi rain barrel system features


The (Multi-Barrel) BlueBarrel Rainwater Catchment System™

To build a multi-barrel BlueBarrel Rainwater Catchment System™, you will need a BlueBarrel DIY RainKit™, and you will need compatible barrels. Luckily you can find all of that right here on this site!

First, decide if you want to order your RainKit™ with Barrels all from BlueBarrel, or if you want a RainKit™ without Barrels (meaning you'll source compatible barrels elsewhere). 

If you purchase our RainKit with barrels, your RainKit and accessories will ship to your doorstep, and you’ll claim unmodified barrels from one of our participating barrel suppliers across the USA. You get to select your preferred local pickup location as part of the ordering process. When you purchase a RainKit, we discount the barrels automatically from full price.

If you plan to supply your own barrels for our RainKits, you need to make sure they are compatible. Check out the compatibility requirements.

Once you add your RainKit(s) to your order, you will see a list of tools required for installation. RainKits do not include tools because you may have many of them already. We list them clearly on our accessories menu so you can easily add what you need:

  • Bung Wrench
  • Pipe Cutter
  • Drill Bits (7/8” & 1-1/16”)
  • Hole Saws (1-1/2” & 2-1/8”)

You will also need to pick up two items at your local hardware store. We have found its cheaper and easier for you to pick these inexpensive items up locally, rather than for us to ship them. Sourcing these items locally also allows you more control over customizable elements like your foundation and barrel spacing:

  • 3/4” PVC Pipe (2.5’ per barrel)
  • Cinder Blocks 8" x 8" x 16" (2 per barrel)

The Single Barrel Option

To order a Single Barrel Kit, start on our Accessories Menu. Add the quantity you’d like, and add any additional tools or accessories you’d like, and proceed all the way through the checkout to complete your order. 

This kit does not include a barrel. If you want to order a barrel from us as well, you will need to place a separate Barrel Order. This will not cost you any extra, as barrels do not have a shipping or handling fee.

The DIY Rain Barrel Kit - Single includes the tools needed for installation: A set of Hole Saws. There are 2 exceptions, and we carry both tools in our Accessories Menu.

  • If you have metal downspouts, you will need a 2-1/8” Hole Saw for Metal
  • If you purchase one of our barrels, we recommend a Bung Wrench to easily open and re-seal your barrels.

The DIY Rain Barrel Kit - Single comes with a 2” x 3” downspout diverter. Since these are pre-packaged kits, these diverters can not be substituted. If you need a different size, we sell 3”x 4” and Round diverter heads separately in our Accessories Menu.

Decide What's Right for You!

We home this article helps you understand the difference between our single and multi-barrel rainwater catchment system offerings.

If you now want to understand how many barrels will work best for you, we have user-friendly online tools for calculating how much rain you can catch, and how much water you might need. We also have a skilled customer service team at the ready to help, should you need it. Check these out, and when you’re ready, you can place your order and start collecting that precious rain!


Article contributed by BlueBarrel's Kelly Nichols.


BlueBarrel is your one-stop-shop for used barrels, DIY rain barrel systems, and gravity-fed irrigation.

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