How to Make a Downspout Diverter? | DIY Rain Barrel Hookup

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Making a downspout diverter on your own involves cutting the downspout, inserting a diverter body, and securing it to route water into a rain barrel.

For the full breakdown, see our best Downspout Diverter guide.

Wondering how to make a downspout diverter rather than buying one? A diverter is the piece that redirects roof runoff from your gutter system into a rain barrel. Whether you build one from scratch or install a kit, the core job is the same: tap into the downspout, catch the water, and steer it to the barrel without leaks or overflow. You’ll need a drill, a hole saw, a hacksaw, self-tapping screws, and eye protection.

What You Need Before You Start

Gather the components first so the installation goes smoothly. A basic diverter setup includes the diverter body itself, a length of hose, and sometimes a diffuser for the overflow. The barrel needs a threaded inlet near the top for the hose to attach.

Position the barrel on a level, stable surface near the target downspout before you cut anything. The barrel inlet must sit close enough for the fill hose to reach without kinking. If the downspout was previously connected to sewer plumbing, cap the opening properly after you cut.

Choosing the Right Diverter Size

Most US homes use standard downspout sizes, and your diverter must match. The two common residential profiles are 2″ x 3″ and 3″ x 4″. Many diverter products, including the Clean Rain Ultra model and Flexi-Fit versions, explicitly support both sizes. This keeps the diverter body low-profile and secure.

Kit contents vary, but most include the diverter body and mounting hardware. The EarthMinded kit, for example, ships with everything needed for a complete rain barrel diverter system. If you’re weighing a DIY build against buying a kit, check our roundup of the best downspout diverters for a side-by-side look at options that fit your gutter setup.

The Step-by-Step Installation Process

Start by marking the cut location. Other kits ask you to measure the diverter body itself and cut a section sized to it. Either way, keep the cut-off piece, as you’ll need it for the bypass or overflow path.

Drill a pilot hole and use a hole saw to open the downspout. Wear safety glasses, gloves, and long sleeves when drilling metal — the shavings are sharp and the edges are unforgiving.

Insert the diverter into the hole with the collection cup facing up and the arrow pointing up. Push straight in rather than twisting, then secure it with self-tapping screws. Pre-drilling usually is not needed. Attach the hose to the diverter outlet and route it to the barrel inlet, adjusting it so it does not kink.

Set the diverter at the same level as the barrel connector, not higher or lower. A height mismatch causes overflow or stops water from reaching the barrel. After everything is connected, run water through the gutter to test the flow and confirm the barrel fills without leaking.

Managing Overflow and Bypass Flow

Heavy rain will fill the barrel, and the overflow has to go somewhere safe. Adding a diffuser at the end of the hose spreads the water out and reduces erosion in the discharge zone.

The cut-off section of downspout you saved earlier becomes part of this overflow path. Reconnect it so water flows past the diverter and continues through the downspout once the barrel is full. This keeps the system functional during storms without flooding the barrel or pooling water against the foundation.

References & Sources

FAQs

Can I install a diverter without cutting the downspout?

No. Every diverter design requires cutting into the downspout to insert the collection cup. You can avoid the cut only by replacing a section of downspout with a pre-built diverter pipe, which achieves the same result through a different method.

What happens to the water when the rain barrel fills up?

Once the barrel reaches capacity, the diverter directs water past the collection cup and down the original downspout. This bypass flow continues to the ground or your drainage system, so excess water never backs up into the gutter.

Does a downspout diverter work with any gutter system?

Diversions fit standard 2″ x 3″ and 3″ x 4″ downspouts, which covers most US homes. Non-standard gutter profiles, such as oversized or custom metal work, may require a different diverter body or professional modification.

References & Sources

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