How To Install a Rainwater Collection Barrel – This Old House

If you’ve ever watched a summer storm and thought, “Wow, there goes my free water bill,” a rainwater collection barrel is your new best friend. Installing a rain barrel is one of those classic This Old House–style projects: simple enough for a weekend, big enough to make a real difference for your yard, your wallet, and your local watershed.

Modern rain barrels are more than just big plastic tubs under the gutter. They’re purpose-built systems with screened lids, downspout diverters, overflow outlets, and sturdy basesall designed to safely capture stormwater and make it easy to reuse for watering gardens, washing tools, and other non-potable tasks. With a few basic tools and a bit of planning, you can install a rainwater collection barrel in an afternoon and start harvesting the next storm.

Why Install a Rainwater Collection Barrel?

Save Money and Reduce Outdoor Water Use

A typical rain barrel holds about 50–60 gallons of water. During a decent storm, a roof area of just 500 square feet can fill a barrel from a quarter inch of rain. That water can replace tap water for tasks like watering flower beds, vegetable gardens, and container plants. Over a season, that adds up to real savings on your water bill, especially in areas with summer watering restrictions.

Help Your Local Watershed

Rain barrels are a simple piece of “green infrastructure.” Instead of letting water rush off roofs, down driveways, and into storm drainspicking up pollutants on the wayyou slow it down and use it on-site. That reduces stormwater runoff, eases pressure on local drainage systems, and helps keep streams and lakes cleaner.

Be Kind to Your Plants

Rainwater is naturally soft and free of chlorine and many dissolved minerals that show up in municipal water. Many gardeners notice that rainwater-irrigated beds look happier and more vigorous. It’s not magic; it’s just water that hasn’t been processed or pushed through a bunch of pipes.

Planning Your Rain Barrel Installation

Choose the Right Location

The best spot for a rainwater collection barrel is right under an existing downspout. Look for:

• Good roof drainage: A downspout that handles a large section of roof will fill the barrel quickly.
• Stable ground: You’ll be placing the barrel on a base that must remain level and solid.
• Convenience: You want the barrel close enough to garden beds or a hose connection that you’ll actually use the water.

A full 55-gallon barrel weighs around 450–500 pounds, so once it’s in place and full, you won’t be casually dragging it across the yard. Plan carefully before you start cutting anything.

Pick a Proper Rain Barrel

You can buy ready-made rain barrels from home centers, garden stores, and online retailers, or assemble your own from a food-grade plastic drum. Look for features like:

• A tight-fitting lid or top with a built-in screen to keep out leaves, debris, and mosquitoes.
• A low spigot with hose threads for filling watering cans or attaching a soaker hose.
• An overflow outlet near the top to direct excess water away from the foundation.
• UV-resistant materials so the barrel doesn’t become brittle in the sun.

If you’re feeling fancy, many manufacturers now offer decorative barrels that mimic wooden barrels, stone urns, or plantersperfect if you want function without the “industrial drum in the yard” look.

Decide on a Direct Feed or a Diverter

There are two common ways to get water from your gutter into the barrel:

1. Elbow method: You cut the downspout and add an elbow that directs water right into the top of the barrel.
2. Diverter kit: You install a downspout diverter that sends water to the barrel when it’s empty and sends overflow back down the downspout when the barrel is full.

A diverter kit is often the easiest and neatest option, especially for beginners. It usually requires drilling a hole in the downspout rather than removing a whole section, and it automatically handles overflow so you’re not flooding your foundation.

Tools and Materials You’ll Need

• Rain barrel with lid, screen, spigot, and overflow fitting
• Downspout diverter kit or metal elbow and connectors
• Level, tape measure, and marker or pencil
• Shovel and hand tamper (or a scrap 2×4) for leveling ground
• Gravel or sand for a compacted base
• Concrete blocks, bricks, or pavers for a raised platform
• Hacksaw or metal-cutting snips (for aluminum downspouts)
• Drill and hole saw (usually 2″–3″, per diverter instructions)
• Flexible hose or tubing for the diverter and overflow
• Optional: Teflon tape for threaded fittings and exterior caulk around connections

Before you start, read through the instructions for your specific rain barrel and diverter kit. They’ll give exact height measurements and hole sizes that matter for a leak-free installation.

Step-by-Step: How to Install a Rainwater Collection Barrel

Step 1: Prepare the Base

The base is the unsung hero of the whole rain barrel installation. A wobbly barrel is not just annoyingit’s unsafe.

1. Clear grass and roots in a square or rectangle slightly larger than your future base.
2. Excavate a few inches of soil so the area is flat and below the surrounding grade.
3. Add a layer of compacted sand or gravel to create a stable, well-draining pad.
4. Set your concrete blocks, pavers, or bricks in a tight formationmany This Old House–style setups use two or three concrete blocks high to raise the barrel.
5. Use a level to check in both directions. Adjust as needed until it’s dead level.

Raising the barrel 12–24 inches gives you better water pressure and more room to fit watering cans under the spigot. Just keep the base wide enough that it won’t tip.

Step 2: Position the Barrel

Set the rain barrel on the base with the spigot facing the direction you’ll be standing when you use it. Make sure:

• The barrel feels stable when you give it a gentle nudge.
• You can easily reach the spigot and any top opening or screen for cleaning.
• There’s space behind the barrel to connect the diverter hose and overflow hose.

Step 3: Mark the Downspout Height

This is where measuring once and cutting twice is a bad idea. With the barrel in place:

1. Hold the diverter or elbow against the downspout at the height of the barrel’s inlet (or per the diverter kit instructions).
2. Mark where the diverter opening or elbow will connect.
3. If you’re using a diverter that installs in the middle of a downspout, follow the manufacturer’s template for the cut or drilled hole.

Take your time here. A diverter installed too high won’t feed the barrel well; too low, and it may not clear the barrel lid or will send overflow in the wrong direction.

Step 4: Cut or Drill the Downspout

Once you’re confident in your marks:

• Use a hacksaw or snips to cut the downspout if required for an elbow or in-line diverter.
• Deburr any sharp edges with a file or sandpaper.
• If your diverter uses a hole instead of a full cut, drill with the specified size hole saw and clean up the edges.

Wear safety glassestiny bits of metal or vinyl in the eye can turn a simple rain barrel project into an urgent care trip.

Step 5: Install the Diverter or Elbow

Attach the diverter or elbow according to the instructions:

• Slide the diverter into the downspout opening and secure it with included screws.
• Make sure it sits upright and angled correctly so water flows toward the barrel.
• Seal any small gaps with exterior-grade caulk if recommended.

Diverter kits typically include flexible tubing that connects the downspout to the barrel inlet. Cut the tubing to length so it runs smoothly without kinks.

Step 6: Connect the Barrel Inlet and Overflow

Now connect the rain barrel itself:

1. Attach the diverter hose to the inlet fitting on the barrel, tightening clamps or threaded fittings securely.
2. Hook up the overflow outlet near the top of the barrel to a hose or pipe that will safely carry excess water away from the foundationideally to a splash block, dry well, or garden bed that can handle occasional flooding.
3. Double-check that the lid or top screen is fully closed and seated.

Many homeowners eventually connect multiple barrels in series: the overflow from one barrel feeds the next. If you go that route, be sure each barrel sits on a similarly solid base and that overflow ultimately has somewhere safe to go.

Step 7: Test the System

Before waiting on the next storm, give your new rainwater collection barrel a test drive:

• Use a garden hose to run water into the gutter or straight into the diverter opening.
• Watch the barrel fill and check all connections for drips.
• Open the spigot and confirm you have a steady flow.
• Let the barrel fill close to the top and make sure overflow goes where you plannednot back against your siding or under the foundation.

If everything looks dry where it should be dry and wet where it should be wet, congratulationsyou’ve just installed a rain barrel like a pro.

Safety, Maintenance, and Mosquito Control

Keep the Water “Yard-Only”

Water collected in a rain barrel is considered non-potable. Don’t drink it, don’t let pets drink it, and don’t connect the barrel to indoor plumbing or outdoor household spigots. Use it for:

• Watering ornamental plants and garden beds
• Soaker hoses and drip irrigation for landscaping
• Washing garden tools or muddy boots

Always check local regulations if you’re planning more advanced rainwater harvesting systems, but for a basic rain barrel, sticking to outdoor, non-food-contact uses keeps things simple and safe.

Defend Against Mosquitoes

Standing water and mosquitoes go together like summer and sunburn, so your rainwater collection barrel needs to be mosquito-proof:

• Make sure the lid closes tightly and any top opening is covered with fine mesh screen.
• Seal around inlet and overflow fittings so gaps are too small for bugs to sneak in.
• Empty and refill the barrel regularly if you’re in a high-mosquito area, or use mosquito “dunks” that are labeled safe for use in water around plants.
• Check that water isn’t pooling on top of the barrel, on lids, or in nearby containers.

Good screening plus a bit of routine maintenance keeps your rain barrel a water saver, not a mosquito factory.

Routine Maintenance

To keep your rain barrel installation working smoothly:

• Clean the top screen periodically to remove leaves and roof grit.
• Flush the barrel once or twice a season to remove sediment.
• Inspect the diverter or elbow after heavy storms to make sure it’s still firmly attached.
• Keep gutters and downspouts cleanclogged gutters mean less water in your barrel and more chance of overflow in all the wrong places.

Seasonal Care and Winterizing

If you live where temperatures routinely dip below freezing, you’ll need to winterize your rain barrel:

• Drain the barrel completely before the first hard freeze.
• Disconnect the diverter hose and either install a winter cover on the diverter or reconnect the downspout straight to the ground.
• Store the barrel upside down or in a sheltered area like a garage or shed.
• Open the spigot so any remaining water can drain and expand without cracking fittings.

In milder climates, you may be able to use the barrel year-round, but still keep an eye out for cold snaps and occasional freezing conditions.

Troubleshooting Common Rain Barrel Problems

Barrel Not Filling

If the barrel barely fills even during a good rain:

• Check that the downspout diverter is oriented correctly and not clogged.
• Confirm that the diverter hole or cutout aligns with the water flow inside the downspout.
• Make sure the inlet hose is not kinked or blocked.

Overflow in the Wrong Place

If water is spilling behind the barrel or pooling at the foundation:

• Double-check the overflow connection and hose routing.
• Make sure the diverter is not stuck partially closed.
• Extend the overflow hose to a spot that can safely handle extra water.

Cloudy or Smelly Water

Some cloudiness or a faint “outdoor water” smell is normal, but strong odors or visible algae mean it’s time for a reset:

• Drain the barrel completely and rinse out sediment.
• Clean the inside with a dilute bleach solution (then rinse thoroughly) or a scrub brush and mild soapavoiding harsh chemicals.
• Replace or clean screens and filters.

Real-World Tips and Experiences from the Yard

Homeowners who install rain barrels all seem to go through the same journey: curiosity, installation stress, then quiet satisfaction every time they water the garden with “storm savings” instead of tap water. Here are some practical lessons that tend to show up after living with a rain barrel for a while.

1. One barrel is a gateway project. Many people start with a single 50–60 gallon rain barrel and quickly realize how fast it fills. A modest summer storm can top it off in minutes. After seeing that, it’s common to add a second or third barrel, either in series on the same downspout or at other corners of the house. If you think you’ll want more capacity later, leave room on the base or nearby for expansion.

2. Elevation is everything. The first time you fill a watering can from a barrel sitting directly on the ground, you’ll understand why all the pros insist on a raised platform. Even a 12–18 inch lift makes a big difference in water pressure. People who upgrade from a low base to a taller, block-style stand often say it’s the single biggest improvement they made after installation. Just make sure that added height comes with extra stabilitywider bases, more blocks, and careful leveling.

3. Downspout diverters are worth the extra effort. Technically, you can just chop the downspout and aim a new elbow into the barrel, but diverter kits earn their popularity. They tend to look cleaner, protect the foundation by redirecting overflow back into the downspout, and are easier to “undo” if you want to take the barrel out of service for winter or maintenance. Many homeowners who started with the elbow method later retrofit diverters for the convenience.

4. Plan the overflow as carefully as the inlet. During heavy storms, the overflow can move a surprising amount of water. People often notice that the first time they see a “mini waterfall” coming out of the overflow spout. Routing that overflow to a rock-filled splash area, a small dry well, or a thirsty garden zone keeps it from eroding soil near the foundation. Some DIYers even run overflow hoses to rain gardens or low landscape spots designed to temporarily hold water.

5. Maintenance is small but non-negotiable. Most of the work happens in tiny chunks of time: scooping leaves off the top screen, checking that the diverter isn’t clogged with roof grit, and draining the barrel if you won’t use the water for a while. Skipping these steps is how you end up with sluggish flow, smelly water, or mosquitoes. Homeowners who set a recurring reminder once a month in peak season tend to have the smoothest experience.

6. Labels save future you. On multi-barrel setups, it’s surprisingly helpful to label hoses and valves: “Overflow,” “To Soaker Hose,” “Winter Bypass,” and so on. Six months later, when you’re reconnecting things in spring or troubleshooting during a storm, those quick notes keep you from playing “guess that hose” in the rain.

7. The satisfaction factor is real. There’s something quietly satisfying about waiting out a storm and then heading outside to see a full barrel ready to go. Many people find the project shifts how they think about watersuddenly, downspouts look less like drains and more like potential water sources. It’s a small, tangible step toward a more sustainable home, and it’s one of those projects that visitors actually notice and ask about.

In short, installing a rainwater collection barrel isn’t just a one-and-done taskit’s the start of a new habit. With a solid base, a good diverter, a mosquito-proof lid, and a bit of seasonal care, your This Old House–worthy rain barrel setup can serve your yard (and your water bill) for years.