If you’ve got one rain barrel, you already know the power of capturing free water straight from the sky. But here’s the thing—one barrel isn’t going to cut it if you want to make a real impact on your water use. A standard 50-gallon rain barrel can fill up in just a single moderate rainstorm.

Depending on your needs, that water can be gone in a week or even a couple of days. So, what do you do when you need more?

You expand.

How Fast Will Your Rain Barrel Fill Up?

If you think a 50-gallon rain barrel will last you all summer, I hate to break it to you—it won’t. In fact, depending on your roof size and local rainfall, it might fill up faster than you can say “water conservation.”

How Much Water Can You Collect from Rain?

Let’s do some quick math. For every 1,000 square feet of roof space, an inch of rain will produce about 600 gallons of water. That means:

• A 500 sq. ft. roof collects 300 gallons per inch of rain.
• A 1,500 sq. ft. roof collects 900 gallons per inch of rain.
• Even a small shed with a 100 sq. ft. roof can pull in 60 gallons per inch of rain.

Now, think about your average rainstorm. If you get half an inch of rain, that’s 300 gallons off a 1,000 sq. ft. roof. Your 50-gallon barrel? It’s overflowing in minutes unless you have a multi-barrel system or an overflow plan.

How Long Will That Water Last?

The real question isn’t how fast your barrel will fill—it’s how long you can make that water work for you.

• Gardening: A small backyard garden can go through 50 gallons in 1-2 weeks, depending on the season. A bigger garden? You’ll need a lot more stored water, especially during a dry spell.
• Flushing Toilets: The average toilet flush uses about 1.6 gallons of water. That means a single rain barrel holds about 30 flushes—enough for a small household for a few days.
• Washing & Cleaning: A quick hand rinse takes about 1 gallon, while washing a car might use 10-15 gallons.
• Emergency Use: If you’re storing water for emergencies, a person needs about 1 gallon per day for drinking and sanitation. That means 50 gallons would last one person about 50 days—but that’s with strict rationing.

The Best Methods to Link Multiple Rain Barrels

So, you’re ready to expand your rainwater collection system—good call. But how do you link multiple barrels together without creating a leaky, inefficient mess? There are a few ways to do it, and each method has its pros and cons.

Let’s start with the Daisy Chain Method, a simple and popular choice.

The Daisy Chain Method (Series Connection)

Photo Source -> [email protected] - Clemson University

The daisy chain method is the rain barrel equivalent of a bucket brigade. One barrel fills up completely before overflowing into the next, and then into the next, and so on. It’s straightforward, requires minimal hardware, and can be set up with a standard hose or PVC pipe.

How It Works

1. The first barrel is connected directly to your downspout.
2. When it fills up, excess water overflows through a hose into the second barrel.
3. This process continues until all barrels are full, with the last one handling any final overflow.

Pros of the Daisy Chain Method

• Easy to set up – Just a few hoses, fittings, and gravity do the work.
• Cost-effective – No need for complex plumbing.
• Expandable – You can add more barrels as needed.

Cons of the Daisy Chain Method

• Uneven water levels – The first barrel fills first, and the last barrel may not get much water if rainfall is light.
• Overflow issues – If your final overflow point isn’t well-managed, you could have water pooling around your foundation.
• Slower drainage – Since water moves barrel by barrel, you might not get even water pressure when using it for irrigation.

The Bottom-Plumbed System (Parallel Connection)

If you want a more efficient way to link multiple rain barrels, the bottom-plumbed system is the way to go. Unlike the daisy chain method, where one barrel fills up before spilling into the next, this setup ensures that all barrels fill and drain evenly.

How It Works

1. Barrels are connected at the bottom using PVC pipes or flexible hoses.
2. As water enters from the downspout, it distributes evenly across all barrels.
3. When you draw water from one barrel, all barrels drain simultaneously.

Advantages of the Bottom-Plumbed System

• Even Water Distribution – Every barrel fills and empties at the same rate, preventing stagnant water.
• Better for Irrigation – Since all barrels act as a single unit, water pressure remains more consistent.
• No Overflow Issues – Unlike the daisy chain method, no single barrel overflows before the others.

Challenges to Consider

• More Plumbing Required – You’ll need additional fittings, pipes, and valves to ensure a proper seal.
• Potential for Leaks – Since all barrels are connected at the base, a single leak can drain the entire system.
• Requires Precise Leveling – If one barrel sits higher than the others, water won’t distribute evenly.

Stacked Rain Barrel Systems

Photo Source -> OSU Extension Service - Oregon State University

For homeowners with limited space, stacked rain barrel systems offer a practical way to increase water storage without taking up additional ground area. By placing barrels on top of each other, you can double or triple your capacity while keeping a small footprint.

How It Works

1. A support structure—such as a heavy-duty wooden or metal frame—holds one or more barrels stacked vertically.
2. Water flows from the top barrel to the lower ones using gravity or a connecting pipe.
3. The bottom barrel serves as the main distribution point for draining water.

Benefits of Stacked Rain Barrels

• Saves Space – Perfect for small yards, patios, or urban environments where ground space is limited.
• Increases Water Pressure – The height of the stacked barrels naturally increases pressure, making it easier to use water for irrigation without a pump.
• Expands Capacity – More storage without sacrificing additional square footage.

Challenges to Consider

• Structural Integrity – A full 50-gallon barrel weighs over 400 pounds. A poorly built support system can collapse, leading to damage or injury.
• Trapped Air Issues – If not properly vented, air pockets can form in the lower barrels, reducing usable capacity.
• Difficult Maintenance – Cleaning or repairing a leak in the bottom barrel requires disassembling the entire stack.

Take Your Rainwater Harvesting to the Next Level

Expanding your rainwater collection system isn’t just about adding more barrels—it’s about maximizing efficiency, conserving water, and making your system work smarter. Whether you go with a daisy chain setup, a bottom-plumbed system, or a stacked barrel approach, each method offers a way to capture more water, reduce waste, and save on utility bills.

Why a Multi-Barrel System is Worth It

• Increased Water Storage – Never let another rainfall go to waste.
• Better Water Pressure – More height and volume means more usable water for irrigation.
• Lower Water Bills – Every gallon collected is one less you pay for.
• Emergency Preparedness – A backup water source for dry spells or unexpected shortages.

You don’t have to build the perfect system all at once. Start with two or three barrels and expand as you see fit. A well-planned system grows with your needs, whether it’s for watering your garden, supplementing household use, or preparing for the unexpected.

Ready to Get Started?

Aquabarrel has everything you need to build a custom, efficient rainwater harvesting system. From barrel kits and downspout diverters to high-quality connectors and overflow solutions, we provide expert-recommended products that ensure your system runs smoothly.

•  Explore our rain barrel kits and accessories
• Get The Earth Minded Rain Barrel Linking Kit
• Check out DIY guides and installation tips

Don’t let another drop go to waste—expand your rainwater collection today and start making the most of what nature provides.