Downspout Diverters: Rain Barrels, Drainage, and Winter Use

We may earn commission from links on this page. Lead-form submissions are forwarded to local inspector partners. How we research and review.

Every downspout on a house delivers a concentrated stream of roof water to one small patch of ground. Where that water goes next matters a great deal for basements, crawl spaces, slabs and landscaping. A downspout diverter is a small fitting that changes the path of that stream, either sending part of it into a rain barrel or swinging it away from the foundation and toward a better discharge point. The hardware is inexpensive and simple, but the way it is installed, set up for winter and paired with overflow routing determines whether it helps or quietly causes problems. This guide explains the main diverter types, how they differ from extensions and splash blocks, what Colorado allows for rain barrel collection, how to handle Front Range freeze-thaw cycles and what a home inspector typically looks at around gutters and drainage.

Part of our Structure & Exterior guide — start there for the full picture →

What a Downspout Diverter Does

A downspout diverter is any fitting installed in or at the bottom of a downspout that redirects some or all of the water away from its default path. The term covers two fairly different products. The first type sits partway up the downspout and taps water off to a rain barrel or other storage container. The second type sits at or near the bottom and swings or switches the flow so water lands farther from the house or in a different direction, such as toward a lawn, a rain garden or a drainage pipe.

Both types share one goal: controlling where roof runoff ends up. The U.S. Environmental Protection Agency’s Soak Up the Rain program describes downspout disconnection as disconnecting a downspout from a pipe or paved area so water is redirected into a rain barrel or onto a lawn or garden where it can soak into the ground. The same page cautions that disconnection may not be appropriate for every location and that homeowners should consider local regulations and where the water will go to avoid property damage or unsafe conditions.

For houses on the Colorado Front Range, where expansive clay soils are common and summer storms can drop a lot of water quickly, the discharge point deserves as much attention as the fitting itself. The broader structure and exterior hub covers how grading, gutters and foundations interact.

Types of Downspout Diverters

Most diverters fall into a few generic categories.

Inline rain barrel diverters

An inline diverter is installed by cutting a section out of an existing downspout and inserting the diverter body in the gap. Inside, a lip or channel catches water running down the inner wall of the downspout and sends it through a side port and a short hose to the barrel. The remaining water continues down the downspout as normal. Many inline models have a lever or rotating insert with two positions: one that sends water to the barrel and one that bypasses the barrel entirely.

Because the diverter only captures part of the flow during heavy rain, the downspout still has to discharge correctly at the bottom. An inline diverter does not replace an extension or splash block. It adds a second path.

Auto-overflow (fill-and-bypass) diverters

Auto-overflow diverters are a variation on the inline style. They rely on water level: the hose to the barrel sits at a height roughly matching the barrel’s top, so once the barrel is full, water backs up in the hose and the diverter automatically sends the rest down the downspout. This avoids the classic rain barrel problem of a full barrel spilling over its rim and soaking the soil right next to the foundation. Installation height matters. If the diverter is mounted too low relative to the barrel, it may not stop filling at the right point; if it is mounted too high, the barrel may never fill.

Flip-up and hinged diverters

Some diverters are simply a hinged section of downspout elbow. In one position, the water runs into a barrel inlet or a collection basin. Flipped the other way, it discharges onto the ground or into an extension. They rely on someone remembering to move them, and a barrel filled by a flip-up diverter with no automatic overflow can spill when it reaches capacity.

Directional diverters for foundation protection

The other broad family has nothing to do with collection. These fittings let a homeowner redirect a downspout sideways or toward a different outlet, for example away from a patio, sidewalk or window well. Some connect to a buried drain line, a pop-up emitter in the lawn or a swale. Others are adjustable elbows or swivel fittings that point the water in a chosen direction. Their value depends entirely on the ground they send the water to: a fitting that turns water toward soil that slopes back at the house has accomplished very little.

Diverters vs Downspout Extensions and Splash Blocks

Diverters, extensions and splash blocks often get lumped together, but they do different jobs. An extension lengthens the discharge path so water lands several feet from the foundation. A splash block is a shaped pad, often concrete or plastic, that slows and spreads water at the outlet so it does not dig a hole in the soil. A diverter changes the direction or destination of the flow.

In practice, many downspouts need more than one of these. A rain barrel diverter still needs a bottom outlet that carries bypass water well away from the house. A directional diverter that points water toward the yard still benefits from an extension long enough to clear the backfill zone around the foundation, and a splash block at the end can keep the discharge from eroding the lawn.

The EPA’s brief guide to mold, moisture and the home recommends cleaning and repairing roof gutters regularly and making sure the ground slopes away from the building foundation so water does not enter or collect around the foundation. A diverter is one tool for following that advice, not a substitute for it.

Colorado Rain Barrel Rules and What They Mean for Diverters

Colorado has historically been one of the stricter states on collecting rainwater, because of how its water rights system treats precipitation. A 2016 state law opened the door for limited residential collection. Under that law, as it is commonly summarized, a single-family household or a multifamily residence with four or fewer units may use up to two rain barrels with a combined storage capacity of no more than 110 gallons, collecting from rooftop downspouts, and the water is to be used outdoors on the same property, such as for lawns and gardens. That summary comes from the state statute rather than a federal source, and rules can change, so homeowners should confirm the current law and any HOA covenants before installing barrels. The rain barrel guide walks through setup and maintenance in more depth.

The 110-gallon limit has a practical effect on diverter choice. A modest roof section can fill a typical barrel in a single moderate storm, which means the bypass behavior of the diverter does most of the work during any heavy rain. In Colorado, an auto-overflow diverter or a barrel with a properly routed overflow outlet is generally more important than maximizing collection, since the household cannot legally store much more anyway.

The EPA notes that rain barrels capture water from a roof and hold it for later use on lawns, gardens or indoor plants, and that collecting roof runoff reduces the amount of water flowing from a property. The agency also points out that rainwater flowing over a roof can pick up pollutants such as bacteria from birds and animals and chemicals from roofing materials, which is worth considering before using barrel water on edible plants. The EPA’s Soak Up the Rain pages carry a disclaimer that they are no longer being updated, so they are best treated as general background rather than current regulation.

Overflow, Foundations and Where the Water Really Goes

The most common failure with rain barrel setups is not the diverter. It is the overflow. A barrel that fills and spills over its rim, or an overflow hose that dumps right beside the barrel, places a concentrated volume of water against the foundation in the exact spot the downspout used to protect. On expansive soils, repeated wetting and drying near a foundation wall can contribute to movement and cracking, and in basements or crawl spaces it can show up as damp walls, efflorescence or musty odors.

A few checks help keep overflow under control:

• Route bypass water out, not down. The downspout below the diverter should end in an extension, a buried line or another outlet that carries water several feet from the foundation.
• Route barrel overflow the same way. If the barrel has its own overflow port, connect a hose or pipe that discharges well away from the house rather than at the base of the barrel.
• Set the barrel level and stable. A full 55-gallon barrel is heavy. A tipping barrel on soft soil can dump everything against the wall at once.
• Check the grade under the barrel. Soil and pavers beneath the barrel should still slope away from the house.
• Keep window wells in mind. A barrel or diverter outlet near a basement window well can flood it. The window well drain guide explains how those wells should handle water.

Where grading is poor or the lot drains toward the house, a diverter cannot solve the problem by itself. Larger fixes such as regrading, swales or a French drain may be needed, and those are better scoped by a drainage contractor after an assessment.

Winter Use: Bypass Mode and Freeze Risk

Front Range winters bring sharp freeze-thaw swings. Sunny afternoons can melt snow on the roof while nights drop well below freezing, which means downspouts often carry meltwater in conditions that freeze it partway down. Diverters add internal edges, channels and hoses where ice can form.

A widely followed practice is to switch any rain barrel diverter to its bypass setting in late fall, disconnect and drain the barrel hose, and empty and store the barrel or turn it upside down so it does not collect water that can freeze and split it. Specific recommendations vary by product, so following the manufacturer’s instructions is the safest approach. If the diverter has no bypass position, some homeowners temporarily replace it with a plain downspout section for the winter.

Ice-related problems near the top of the system also affect diverters. When gutters are packed with debris, water can freeze in the trough and build up at the eaves. That contributes to ice dams, which are usually driven by heat loss into the attic and inadequate insulation or ventilation. A frozen or blocked downspout can make the backup worse, sending meltwater over the gutter edge and down beside the foundation instead of through the downspout and diverter. Clearing the diverter screen and the downspout before the first hard freeze helps.

Gutters, Debris and Diverter Maintenance

A diverter can only pass along what the gutter sends it. Leaves, pine needles, shingle granules and seed pods wash into downspouts and collect on diverter screens and inlet lips. When the screen clogs, water may back up and overflow the gutter or bypass the barrel entirely without anyone noticing.

Routine gutter cleaning, usually at least in late spring and again in fall after leaves drop, keeps diverters working. Homes under heavy tree cover may need more frequent attention. Some homeowners add gutter guards to reduce debris, though guards still need periodic cleaning and can create their own problems with ice and with heavy flow overshooting the gutter.

A simple maintenance routine for a rain barrel diverter usually includes:

1. Checking the diverter screen or inlet after major storms and removing debris.
2. Flushing the barrel hose and confirming water reaches the barrel.
3. Confirming the overflow works and discharges away from the house.
4. Inspecting the barrel lid and screen to keep out mosquitoes, debris and small animals.
5. Switching to bypass and draining everything before winter.

Downspout Diverter Costs

Costs vary by material, brand, region and whether a handyman or gutter contractor does the work, so the figures below are rough estimates rather than quotes. Hardware for a basic flip-up or swivel diverter is often in the range of about $10 to $30. Inline rain barrel diverters, including auto-overflow models, commonly fall somewhere around $20 to $60. A complete rain barrel kit with a barrel, diverter, spigot and overflow fittings may run from roughly $80 to $250 or more depending on size and finish.

Professional installation for a diverter is usually a small job. Some gutter contractors fold it into a service call or a cleaning visit; others charge a minimum trip fee that can make a single fitting relatively expensive. Larger drainage work changes the math completely. Buried downspout lines, pop-up emitters and regrading can run from a few hundred dollars to several thousand, and the French drain cost guide covers the much larger projects that sometimes follow persistent water problems.

What a Home Inspector Looks At

Under the American Society of Home Inspectors Standard of Practice, a home inspector inspects roof drainage systems, which the standard defines as components used to carry water off a roof and away from a building. Inspectors also inspect vegetation, grading, surface drainage and retaining walls that are likely to adversely affect the building. The same standard lists geological and soil conditions and erosion control measures among the items an inspector is not required to inspect.

In practice, an inspector walking the exterior may note downspouts that discharge at the foundation, missing or disconnected extensions, diverters stuck in a barrel position with no working overflow, barrels sitting on soil that slopes toward the house and staining or erosion near outlets. Inside, signs such as damp basement walls or water marks below a downspout location can point back to the same issue. An inspector will generally recommend correction by a gutter, drainage or grading contractor rather than designing the fix. The hiring process section explains how to choose an inspector and what to expect in the report.

More Questions About Downspout Diverters

How do you install a downspout diverter?

A downspout diverter is installed by marking the downspout at the height of the rain barrel inlet, cutting out a section with a hacksaw or tin snips, and fitting the diverter into the gap.

Most kits include a hose that runs from the diverter to the barrel, and the barrel should sit level on a firm, raised base so the inlet lines up and a watering can fits under the spigot. Secure the downspout above and below the diverter with straps. Check that the overflow or bypass returns water into the downspout and then to an extension that carries it away from the foundation.

Do downspout diverters work with all downspout sizes?

Downspout diverters are made for common residential sizes, most often 2×3-inch and 3×4-inch rectangular downspouts, and round downspouts in several diameters, but no single diverter fits every size.

Some models include adapters for multiple sizes. Measure the downspout’s outer dimensions before buying, and note whether it is aluminum, vinyl, steel or copper, since cutting and sealing methods differ. Oversized downspouts on large roofs can overwhelm small diverters in heavy rain, so models with a full bypass or a larger hose outlet handle high flows better.

Can a downspout diverter send water to a garden or lawn?

Yes, a downspout diverter can send roof water to a garden, rain garden or lawn area, as long as the water ends up at least several feet from the foundation and does not flow toward neighbors’ property.

Flexible hoses, soaker hoses connected to a barrel, or a diverter feeding a shallow swale are common setups. Avoid discharging onto steep slopes, septic drain fields, or near window wells. Roof runoff can carry debris and residue from roofing materials, so many gardeners avoid using it on edible plants’ leaves. Local rules on collecting or redirecting rainwater should be checked first.

What size rain barrel works with a downspout diverter?

A 50 to 60 gallon rain barrel is the most common size used with a downspout diverter, and it fills quickly; even a modest rain on a small roof section can fill one barrel.

Larger tanks or linked barrels store more water but need stronger bases, since a full 55-gallon barrel weighs over 400 pounds. The diverter’s overflow or bypass handles the extra water once the barrel is full. Local rules can limit total storage, so check before adding barrels. A screened inlet keeps out mosquitoes and debris, and a lid keeps children and animals safe.

References

• Soak Up the Rain: Disconnect / Redirect Downspouts — U.S. Environmental Protection Agency
• Soak Up the Rain: Rain Barrels — U.S. Environmental Protection Agency
• A Brief Guide to Mold, Moisture and Your Home — U.S. Environmental Protection Agency
• ASHI Standard of Practice for Home Inspection — American Society of Home Inspectors

Seeing water pool by the foundation after storms? Reach out to us and we can point you toward a Front Range inspector who checks exterior drainage.