8 Supplies for Installing a Rainwater Harvesting Diverter

Collecting rainwater is one of the smartest moves you can make on a small farm, turning a free resource into a lifeline for your gardens and livestock. But the success of your system hinges on a single, critical connection: the diverter that joins your downspout to your barrel. Getting this small installation right means a leak-free, efficient system for years to come, and it all starts with having the right tools on hand before you make the first cut.

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Gearing Up for Your Rainwater Diverter Install

Installing a rainwater diverter is a straightforward job, but it’s one where precision matters. A sloppy cut or a poor seal will turn your water-saving system into a water-wasting leak right next to your foundation. The difference between a frustrating afternoon and a successful 30-minute project is having every tool you need laid out and ready before you begin.

This isn’t the time to improvise. Trying to eyeball a straight line or using the wrong sealant will create problems that are much harder to fix later. By gathering these specific supplies, you’re not just buying tools; you’re buying a clean cut, a perfect fit, and a leak-proof seal. This list is built from experience and is designed to get the job done right the first time, with no extra trips to the hardware store.

Rainwater Diverter – Fiskars Rain Barrel DiverterPro

The diverter is the heart of the operation, channeling water to your barrel when it’s empty and automatically bypassing it when it’s full. The Fiskars Rain Barrel DiverterPro Kit is an excellent choice for most hobby farm setups because it’s a complete, well-designed system. It includes the diverter body, a connecting hose, seals, and even a drill bit for the downspout hole, removing much of the guesswork.

What sets the Fiskars model apart is its internal reservoir and automatic overflow design. When the rain barrel fills, water backs up into the diverter and is redirected down the original downspout path, preventing messy and potentially damaging overflows. It’s designed to fit standard 2×3-inch and 3×4-inch rectangular downspouts, which covers the vast majority of residential and outbuilding gutters. This kit is ideal for anyone looking for a reliable, all-in-one solution that minimizes potential points of failure. It’s a plug-and-play system for people who want to harvest water, not become plumbing experts.

Hacksaw – DeWalt 12-inch High-Tension Hacksaw

You need a hacksaw to make a clean, straight cut through your existing downspout to insert the diverter. This is the most critical step, and a flimsy, low-quality saw will wander, bend, and leave you with a jagged edge that’s impossible to seal. A high-tension hacksaw is essential because it keeps the blade rigid, allowing for precise control.

The DeWalt 12-inch High-Tension Hacksaw is the right tool for this job. Its robust frame lets you tension the blade up to 330 lbs, which translates to a dead-straight cut with minimal effort. The saw also allows for 90-degree and 45-degree blade angles, which can be useful for cutting in tight spaces against a wall. Pair it with a 24 TPI (Teeth Per Inch) bimetal blade for a smooth finish on thin aluminum or vinyl downspouts. This tool isn’t for someone who needs to make one rough cut; it’s for the person who understands that a clean cut is the foundation for a waterproof seal.

Tape Measure – Stanley PowerLock Tape Measure

Accuracy is everything. You’ll use a tape measure to determine the correct height for your diverter based on your rain barrel’s inlet, and to mark the section of downspout that needs to be removed. Being off by even a quarter of an inch can compromise the seal or create drainage problems.

The Stanley PowerLock 25-foot Tape Measure is a classic for a reason. It’s durable, the blade has a clear coating for longevity, and the thumb lock is solid and reliable. You don’t need a fancy digital measure; you need a tool that gives you a consistent, easy-to-read measurement every time. The 1-inch wide blade has enough standout to make measuring alone easy, and its rugged case can handle being dropped. This is a foundational tool for any farm, and it’s the perfect choice for ensuring your diverter installation is measured twice and cut once.

Marking Pen – Sharpie Fine Point Permanent Marker

Once you’ve measured, you need to transfer that measurement to the downspout with a clear, precise line. A pencil won’t show up well on metal or vinyl, and a thick marker can make your cut line ambiguous. The goal is a razor-thin guide that your hacksaw blade can follow exactly.

A Sharpie Fine Point Permanent Marker is the perfect tool. It creates a crisp, dark line that’s easy to see and won’t smudge or wipe away as you handle the downspout. It works equally well on painted aluminum, bare metal, or plastic PVC downspouts. For dark-colored downspouts, a silver metallic Sharpie is an even better choice. This isn’t a place to overthink it—you just need a reliable marker that makes a line you can trust.

Cordless Drill – DeWalt 20V MAX Drill/Driver Kit

You’ll need a drill for two key tasks: creating the initial hole in the downspout where the diverter outlet will connect, and drilling the larger inlet hole in your rain barrel. While some diverter kits come with a small bit, a capable cordless drill provides the power and control needed for a clean job, especially on the barrel itself.

The DeWalt 20V MAX Drill/Driver Kit is a versatile workhorse that belongs in every farm workshop. Its variable speed trigger is crucial here—it lets you start holes slowly to prevent the bit from "walking" and allows you to control the speed to avoid cracking the plastic of the rain barrel. The power is more than sufficient for driving a hole saw (sold separately) through the side of a thick plastic drum. This drill is an investment, but its utility extends to countless other projects, from building fences to repairing equipment. It’s for the person who wants a reliable tool that will handle this task and hundreds more.

Ensuring a Level and Accurate Downspout Cut

The single biggest mistake in this installation is making an angled or uneven cut in the downspout. A crooked cut creates gaps that even the best sealant can’t reliably fill, leading to persistent drips. The key is to create a perfect guide line that wraps around all four sides of the downspout.

Forget trying to eyeball it. The best method is to use a piece of wrap-around material as a guide. Take a sheet of paper, a piece of thin cardboard, or even a flexible plastic folder and wrap it tightly around the downspout, aligning the edge with your measurement mark. When the edge of the paper lines up with itself perfectly, you have a dead-straight line. Trace this line with your Sharpie, and you’ll have a foolproof guide for your hacksaw. This simple technique takes 30 seconds and guarantees a professional-quality cut.

Silicone Sealant – GE Advanced Silicone 2 Sealant

Once the diverter is in place, you need to create a permanent, waterproof barrier around it. This is not a job for cheap painter’s caulk or interior-grade silicone. You need a sealant that can withstand constant exposure to water, temperature swings, and UV rays without cracking or peeling.

GE Advanced Silicone 2 Window & Door Sealant is the right choice. It is 100% silicone and 100% waterproof, offering excellent flexibility and adhesion to metal, vinyl, and plastic. It’s also permanently weatherproof, with a 30-minute rain-ready time that’s helpful when you’re working between storms. Applied with a standard caulk gun, a neat bead around the top and bottom seams of the diverter will ensure not a single drop of water escapes where it shouldn’t. This is your final defense against leaks, so using a high-quality, exterior-grade product is non-negotiable.

Work Gloves – Gorilla Grip All-Purpose Work Gloves

Cutting metal, even thin downspout aluminum, creates razor-sharp edges. Handling the freshly cut pieces without hand protection is asking for a nasty slice. Good work gloves provide both protection and an enhanced grip on your tools.

Gorilla Grip All-Purpose Work Gloves are ideal for this kind of task. They offer a fantastic balance of protection and dexterity. The polymer coating gives you a secure hold on the hacksaw and drill, while the breathable knit shell keeps your hands from getting too sweaty. They are thin enough that you don’t lose your sense of touch, but tough enough to protect you from the sharp burrs on the cut downspout. They’re an inexpensive piece of gear that prevents a simple job from turning into a trip for bandages.

Safety Glasses – 3M Virtua CCS Protective Eyewear

Drilling and cutting create flying debris. Tiny shards of metal or plastic can be ejected at high speed, and your eyes are the most vulnerable target. This is a simple, non-negotiable safety step.

The 3M Virtua CCS Protective Eyewear is a great option because it’s lightweight, comfortable, and provides excellent coverage with integrated side shields. The anti-fog coating is a practical feature that keeps your vision clear, even if you’re working on a humid day. They meet ANSI Z87.1 standards for impact protection. There is no excuse for skipping eye protection; a five-dollar pair of glasses is the best insurance you can buy against a serious, permanent injury.

Choosing the Right Spot for Your Rain Barrel

Where you place your rain barrel is just as important as how you install the diverter. The first rule is that the barrel must sit on a solid, level surface. A full 55-gallon drum weighs over 450 pounds, and it will sink into soft ground, putting stress on the diverter hose and potentially tipping over. A base of leveled paver stones or cinder blocks is an ideal foundation.

The height of the base also matters. Elevating your barrel a foot or two off the ground provides two key benefits. First, it ensures the barrel’s inlet is lower than the diverter, allowing gravity to do its work. Second, it raises the spigot at the bottom, making it high enough to fit a watering can underneath or to provide enough head pressure for a short soaker hose. Finally, always consider the overflow. Position the barrel so that if the diverter’s internal bypass ever fails, the overflow will drain away from your home’s foundation, not towards it.

Final Checks for a Leak-Free Installation

Once the sealant has had time to cure according to the manufacturer’s instructions (usually a few hours), it’s time for a final inspection. Don’t wait for a downpour to discover a problem. Use a garden hose to run a small amount of water into the gutter above the downspout to simulate a light rain.

Carefully watch every connection point. Check where the diverter meets the top section of the downspout and where it meets the bottom. Inspect the connection between the diverter and the flexible hose, and where the hose connects to the rain barrel. If you see even a tiny drip, now is the time to dry the area thoroughly and apply another small, targeted bead of sealant. A leak-free test run gives you the confidence that your system is ready to perform perfectly when the real rain arrives.

With the right tools and a bit of careful work, you’ve installed more than just a piece of plumbing; you’ve created a resilient water source for your farm. This small project pays dividends every time it rains, reducing your reliance on municipal or well water and connecting your garden directly to the cycle of nature. Now, you can spend less time worrying about leaks and more time putting that precious rainwater to good use.