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Best Shallow Design
Best Recycled-Plastic Option
A slim rain barrel is useful when the downspout sits beside a walkway, narrow patio, side yard, fence line, or shed where a wide round barrel would stick out too far. The goal is not simply to buy the smallest container. It is to keep enough clearance for people, doors, gates, hoses, and overflow while still giving the barrel a stable base.
Flat-back designs help because they waste less space behind the barrel. But a barrel should not be jammed hard against a wall. Plastic can bow when full, fittings need room, and you still need access to the inlet, overflow, and outlet for maintenance.
The four options here all use wall-side shapes rather than broad round tanks. The best choice depends on how much depth you can spare, whether you need a removable lid, and how much maintenance access you want after installation.
The related explainer “What Is a Good Rain Barrel for Small Spaces?” helps prevent a storage choice that is too small or difficult to maintain.
Slim Rain Barrels at a Glance
| Product | Best For | Main Strength | Main Tradeoff |
|---|---|---|---|
| RTS Home Accents Flat-Back Rain Barrel | Best all-around tight-space fit | 21 x 19 in documented footprint and brass spigot | Capacity field conflicts |
| FCMP Outdoor Slim Line Rain Barrel | Shallow wall-side placement | Purpose-built slim-line form with linking and overflow hardware | Dimension/capacity fields conflict and cracking has occurred |
| RTS ECO Flat-Back Rain Barrel | Recycled-plastic design | 24 x 19 in documented footprint and flat back | Screen fit, bowing, and spigot leaks can occur |
| RTS Premium Eco Rain Barrel | Easier cleaning access | Removable lid and flat back | Wider footprint and leak complaints make it less ideal for very tight spaces |
Measure the Walking Space After the Barrel Is Full
Do not measure only from the wall to the empty barrel. Leave clearance for a hose, spigot handle, overflow line, and any body movement under load. A flat-backed plastic barrel can expand or bow slightly once it holds hundreds of pounds of water.
Also check the path beside it. If a gate needs to swing open or a lawn mower has to pass, mark that clearance on the ground before buying. A barrel that technically fits but blocks daily access will become an annoyance quickly.
Finally, make sure the base is wider than the barrel footprint. A narrow container still needs full support under the bottom.
The planning note “What Is the Point of a Rain Barrel?” helps prevent a storage choice that is too small or difficult to maintain.
A Compact Flat-Back Barrel With a Brass Spigot
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RTS Home Accents Flat-Back Rain Barrel
Footprint
21 x 19 in documented
Height
34 in documented
Back
Flat
Spigot
Brass
The RTS Home Accents flat-back barrel has the strongest tight-space case because its documented 21-by-19-inch footprint stays relatively compact while the back sits close to a wall or fence. The brass spigot also gives it a more substantial outlet than many lightweight plastic taps.
Reported use is simple but encouraging: setup is straightforward, the body feels solid rather than flimsy, and the top screen and spigot are useful without much modification. That makes it a good choice for a homeowner who wants a narrow, conventional barrel rather than a collapsible system.
The capacity field conflicts, so this recommendation does not depend on an exact gallon figure. Choose it for the compact documented footprint, flat-back shape, screened inlet, and brass outlet.
Why It Works
- Documented 21-by-19-inch footprint is manageable in narrow areas.
- Flat back reduces wasted space behind the barrel.
- Brass spigot gives a durable-feeling outlet.
- Screened top helps reduce larger roof debris.
What To Keep In Mind
- Capacity is omitted because available product details conflict.
- Leave clearance behind the barrel instead of pressing it tightly to the wall.
- A stand may help bucket access but must support the full water load.
A Purpose-Built Slim-Line Barrel
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FCMP Outdoor Slim Line Rain Barrel
Design
Slim line
Back
Flat
Included
Hose, shut-off valve, overflow hose and linking kit
Inlet
Debris screen
The FCMP Slim Line is the most obviously space-focused design in the group. Its shallow body and flat back are specifically intended for smaller outdoor areas, and the included hose, shut-off valve, overflow hose, and linking hardware make it easier to build a compact system without collecting many separate fittings.
The comparison “What Are Some DIY Ideas for a Rain Barrel?” connects the storage choice to overflow control and water quality.
The tradeoff is durability confidence. Reported problems include a cracked barrel within a year and small hardware that needed repair or reinforcement. Its dimension, material, and capacity details also conflict, so exact measurements are not used as buying claims here.
This is the right pick when the shape itself solves a real placement problem. If you have a few more inches to spare, the RTS flat-back model above gives a cleaner evidence profile.
Why It Works
- Slim-line body is made for shallow wall-side placement.
- Flat back makes downspout alignment easier in tight areas.
- Overflow and linking hardware are included.
- Debris screen helps protect the stored water from larger material.
What To Keep In Mind
- Long-term cracking has occurred.
- Small hose hardware may loosen during use.
- Exact dimensions and capacity are omitted because those fields conflict.
A Flat-Back Barrel Made With Recycled Plastic
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RTS ECO Flat-Back Rain Barrel
Footprint
24 x 19 in documented
Height
34 in documented
Back
Flat
Material
Plastic
The RTS ECO gives you another narrow wall-side form with a documented 24-by-19-inch footprint. It uses recycled-plastic construction and keeps the same basic flat-back idea: more of the available space goes into the barrel rather than a round gap behind it.
Its main weakness is consistency around the inlet and outlet. Reported problems include screens that do not sit correctly, spigot leaks, warped bodies, and barrels that bow toward the wall once full. That means you should leave rear clearance even though the design is marketed for close wall placement.
The capacity field conflicts, so do not use an exact gallon claim for planning. This model is most appealing when recycled-plastic construction matters and the 19-inch documented depth fits your site.
Why It Works
- Documented 19-inch depth suits narrower wall-side spaces.
- Flat-back body reduces wasted rear clearance.
- Recycled-plastic construction is a clear differentiator.
- Basic inlet screening helps stop larger debris.
What To Keep In Mind
- Screen fit and spigot sealing can be inconsistent.
- The body may bow when full, so leave space behind it.
- Inspect the barrel for malformed openings or shipping damage before installation.
A Wider Flat-Back Barrel With a Removable Lid
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RTS Premium Eco Rain Barrel With Removable Lid
Footprint
33.5 x 21.25 in documented
Height
33.5 in documented
Back
Flat
Lid
Removable
The RTS Premium is the least slim option here, but it earns a place because its flat back and removable lid solve two problems that narrow installations often create: limited wall clearance and difficult cleaning access. The lid lets you inspect or reach into the barrel without working through a small inlet opening.
Its documented footprint is wider and deeper than the other rigid options, so it only makes sense if your site has the room. Reported problems also include spigot drips, body defects, and warping on some units.
The capacity field conflicts and is omitted. Choose this barrel when removable top access is more important than squeezing the container into the shallowest possible space.
Why It Works
- Removable lid makes cleaning and inspection easier.
- Flat back still suits a wall-side installation.
- Direct top access can make watering-can filling quick.
- Rigid body avoids the support-frame issues of collapsible barrels.
What To Keep In Mind
- Documented footprint is larger than the other slim-focused choices.
- Inspect the spigot and body for leaks during the first fill.
- Do not rely on a conflicted capacity claim.
How Much Clearance Does a Slim Barrel Need?
Leave enough room to operate the spigot, attach or remove a hose, inspect the overflow, and clean the inlet. A few inches of service space can make a big difference later.
If the barrel sits beside a path, consider the widest part of a watering can or hose fitting, not just the barrel body. If it sits near a gate, test the full swing before the barrel fills.
The downspout also needs a clean route into the screened inlet. Avoid forcing flexible extensions into a sharp bend just because the barrel is tucked into a corner.
Slim Barrel Placement Tips
Keep the Base Completely Level
A narrow container can feel stable because it takes up little space, but a tall water column still creates a heavy load. Support the whole base evenly.
Leave Rear Clearance
Flat-back does not mean zero clearance. Leave room for body movement, fittings, and inspection.
Plan the Overflow Side
Do not let overflow dump into the narrow path beside the barrel. Route it away from the foundation and away from the base.
Raise Only on a Proper Stand
A stand can improve faucet clearance and gravity pressure, but it must be wide enough and rated for the filled barrel.
Keep the Inlet Reachable
Slim installations are often wedged between walls, fences, and shrubs. Make sure you can still remove leaves and clean the screen.
Common Problems in Tight Installations
The Barrel Blocks a Walkway
Reposition it before filling. Once full, a rain barrel is too heavy to slide safely.
The Body Touches the Wall When Full
Drain enough water to relieve the load, then create more clearance. Repeated rubbing can damage the wall or make maintenance impossible.
The Hose Pulls on the Spigot
Support the hose instead of letting its weight hang from the fitting. Side load can create leaks in plastic barrel walls.
Overflow Washes Out the Base
Extend the overflow route beyond the barrel pad. A narrow side yard often concentrates runoff, so drainage matters.
Frequently Asked Questions
What is the best rain barrel for a narrow side yard?
A flat-back barrel with a shallow footprint is usually easiest to place. Measure wall depth, walkway clearance, downspout location, and overflow before choosing.
Can a slim rain barrel sit directly against a wall?
Leave some clearance. Plastic can bow when full, and you need room for fittings, inspection, and airflow around the barrel.
Does a slim rain barrel hold less water?
Not necessarily, but shape affects capacity and height. Choose the barrel from the available space and intended water use rather than assuming a narrow shape always means low storage.
Can I connect two slim rain barrels?
Yes when the barrels have compatible linking ports or a suitable connector kit. Keep both containers level so water can balance between them.
How can I improve water flow from a slim rain barrel?
A stable raised stand can improve gravity head and bucket clearance. Keep the hose reasonably short and route it downhill when possible.
Are flat-back barrels easier to install under a downspout?
Often yes because they sit closer to the wall, but you still need to align the inlet, provide service clearance, and route overflow safely.
For a broader comparison beyond narrow designs, see the main rain barrel guide. If you need more storage without a wider permanent container, collapsible rain barrels offer seasonal options that fold down when empty. For expanding a narrow setup with a second barrel, rain barrel linking kits cover compatible connection approaches. And if low outlet height makes watering awkward, rain barrel spigots can help you compare replacement outlets and hose connections.
