Downspout diverters make it incredibly simple to get started with rainwater harvesting.
This guide will go over what you need to know about how downspout diverters work, the different types of diverters, when filters are necessary, how to install, and the best downspout diverters for rainwater harvesting.
Our Top Pick
|Diverter||Type||Filter||Overflow Protection||Number of Outlets||Sizes|
|Earthminded Flexifit||Hose||No||Yes||1||3 and 4” round, 2x3 or 3x4 rectangular|
|Amerimax Diverter ||Hose||Yes||Yes||1||2x3|
|Save the Rain||Arm||No||No||1||2x3|
|Gutterworks diverter||Y||No||No||2||2x3 and 3x4|
|Fiskars DiverterPro||Hose||Yes||Yes||2||2x3 and 3x4|
Best Rain Barrel Diverters for Rainwater Harvesting
Earthminded Flexifit Downspout Diverter
The Flexifit downspout diverter by Earthminded is one of the most popular. The reason for this is because it’s the easiest to install.
All you need to do is drill a round hole in your downspout. Because the diverter is made of flexible material, it easily fits into the hole. You then screw it in place and connect it to your rain barrel hoses.
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The diverter catches water along the outside of the downspout but still allows water to pass through. This means you won’t need an overflow outlet on your rain barrel.
However, the diverter does narrow the size of your downspout, potentially causing clogs. Make sure you put some screens leaf catchers over your downspouts. Also regularly remove the Flexifit diverter to check for clogs.
If you only need the diverter and winterizing cap, you can buy it as a universal diverter for rectangular downspouts or for round downspouts. They also have an affordable kit that includes the diverter, hole saws, spigots and hoses.
- Incredibly easy installation
- Fits all residential downspouts
- Kits include everything needed for installation
- Easy to remove for cleaning
- Doesn’t leak
- Good overflow protection
- No filter
Oatey Mystic Rainwater Downspout Diverter
The Oatey Mystic is a two-piece PVC rainwater diverter. To install, you need to cut a section of your downspouts and insert the diverter. Then just connect the hose to the outlet and your rain barrel’s inlet.
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The interior of the Mystic diverter is fairly large, so it isn’t likely to clog even if you have dirty gutters. However, that means it’s not as good at collecting rainwater as some diverters, especially in light rains.
While the Mystic doesn’t have a filter and only has one hose outlet, it does have a good design: the bottom of the diverter sits inside the downspout, meaning that leaks won’t occur like with the Fiskars diverter.
Note that the winterizing stopper is really flimsy. You’ll probably need to replace it with one made of stronger rubber.
- Good design
- Holds up well even in very cold winters
- Fairly easy to install
- Won’t fit 3×4 or round downspouts
- Only has one hose outlet
- Short hose
- Winterizing stopper is flimsy and will need to be replaced
Downspout Diverter with Filter Basket (2×3”)
This downspout diverter is sold under many different brand names. Its main feature is that it has a built-in filter basket. Because you annoyingly have to disconnect the diverter to access the filter, you probably won’t empty the filter often.
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However, the diverter does have one other really nice feature: its outlet is a standard garden hose connection. This is great if your rain barrels are located far away from the downspout.
Unfortunately, as with the Fiskars, the diverter sits over the downspout rather than inside it – meaning that leaks can occur. Still, it does its job well and is a good pick if you don’t want to bother adding a hose adapter to an outlet.
- Has filter
- Garden hose compatible
- Very cheap
- Filter basket is annoying to access
- May leak a bit
Save the Rain Metal Diverter
This is a very simple rainwater diverter. When the 7 inch arm is open, it channels water outwards towards a rain barrel with a large opening. To stop diverting water, just close the arm.
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For its type, it does exactly what it is supposed to do. However, as you’d expect with this type of downspout diverter, water splashes all over the place. It’s also hard to control where the water will land.
It isn’t recommended if you are worried about damaging the foundation of your home.
- Very simple design
- Diverts all water in downspout
- Easy to open and close
- Hard to control water flow
- Can’t connect to a hose
- Lots of splashing
Gutterworks.com Y Downspout Diverter
This is a Y type downspout diverter that has a switch in the middle. You can set the switch so all of the water goes to either the left or the right. When the switch is in the middle, half of the water will flow to each side.
While the design means there is no overflow protection, it does give you a lot of flexibility with how you set up your rain barrel system. The diverter is made of metal so is very durable and you won’t have to worry about it withstanding harsh winters.
- Made of durable metal
- 2×3 and 3×4 sizes
- Available in many colors
- Lever allows you to divert water left or right
- No features like overflow protection or a filter
The standout feature of the DiverterPro by Fiskars is that it has a built-in filter. Unlike other downspout diverters with filters, the Fiskars is actually easy to use. The filter hood is see-through so you know when it needs to be cleaned. To clean, just lift the hinged hood and remove any debris inside.
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To install the Fiskars DiverterPro, you will need to cut out a small section of your downspout with a saw. It fits 2×3 and 3×4 downspouts and comes with a hose and a barrel connector. There are outlets on both sides so you can connect a barrel on each side of the diverter.
When your rain barrel is full, the diverter will divert the water back down your downspout, away from your house and foundation. This eliminates the need to monitor your barrel and reduces the risk of your rain barrel overflowing.
An annoying design flaw about the DiverterPro is that it sits outside of the downspout instead of inside it. This means that some water may leak out the bottom and trickle down the downspout.
- Filter is easy to clean
- Clear hood to view filter
- Fits 2×3 and 3×4 downspouts
- Two outlets allow you to connect rain barrels on each side
- Hose is short
- Need to modify it to use with garden hose
- Some leakage from below diverter
How Do Rain Barrel Diverters Work?
Downspout diverters attach to your downspouts. They have switches or funnels which allow some or all of the water flowing through the downspout to go through a separate exit instead. The exit (such as a hose) is connected to your rainwater barrels.
You do not need to use a downspout diverter for rainwater harvesting if you set up your system so the gutter empties directly into the rain barrel. However, there are many benefits to using a downspout diverter.
Benefits of Using a Downspout Diverter
Hose-type downspout diverters create a closed system: the hose is connected directly to the barrel and there’s no need for an overflow port. This means that there are fewer places for mosquitoes and other pests to enter your barrels and also fewer places for leaks to occur.
*Note that not all types of downspout diverters create a closed system.
Most downspout diverters have overflow protection: when the rain barrel is full, the rainwater will simply fall through the main gutter. This ensures that the barrels don’t overflow and damage your home’s foundation.
Without a downspout diverter, you will need to have an overflow port on your rain barrels. Unfortunately, sizing overflow ports can be tricky. During heavy storms, the water might not be able to exit the port fast enough and can cause the barrel to overflow and damage your property.
Debris continues to flow through downspout:
Downspout diverters do not completely block off the downspouts, so debris from your gutters is still able to pass through. This helps keep debris out of your rain barrels so they stay clean.
Cons of Downspout Diverters
Because downspout diverters allow much of the rain to flow down the middle, they are very inefficient. This usually isn’t an issue for people with small rainwater harvesting systems though.
Even if the diverter only catches 20% of the rain, it will still be able to fill up a 55-gallon barrel during a 1” shower (see our rainwater harvesting calculator here).
However, if you need to harvest large amounts of water and live somewhere with infrequent rains, inefficiency can be major issue. You’ll probably be better off setting up a system where the gutters flow directly into the rain barrels.
Types of Downspout Diverters
These are the most popular type of downspout diverters. They have a partial funnel inside of them. The funnel catches water as it flows through the downspout and channels it through a hose into your rainwater barrels.
Because the funnel doesn’t completely block the downspout, debris can still flow through.
It also allows for a completely closed system: once the rain barrel is full the water will back up into the hose and drain back into the downspout. You won’t need an exit port on your rain barrels.
3-Way Wintering Tee Diverter
This is a very basic way to set up a rainwater harvesting system. You simply replace one section of pipe with a 3-way tee (usually made out of PVC).
The tee has a plunger in it which is used to close off one of the outlets. The plunger can be set so all water from your gutters goes directly into your rainwater barrels. In winter, the flap is closed so no water enters your rainwater harvesting system. Some wintering tees have built-in filters.
Y-shaped rainwater diverters are almost always made out of metal and thus are more durable. There is usually a switch in the Y which allows you to choose which direction the rainwater will flow through the diverter.
This gives you more flexibility when setting up your system. For example, you can close the switch when your rain barrel is full. Or you can put the switch in the middle setting and have it divert water to two barrels.
Y-shaped diverters aren’t great options for many homes though. There is no overflow protection. They don’t keep debris out of the barrels, which could result in clogs and overflow. They are also very bulky and a bit trickier to install than most hose diverters.
Arm rainwater diverters (like the one by Save the Rain) are basically a piece of downspout with a flap that you can open and close. When open, some of the rainwater flows out.
There is no hose connection though, so you have to carefully position the rain barrel underneath it. You’ll need a very large inlet hole to catch the water as it flows out.
Even with a large inlet, you can still expect a lot of splashing. This makes arm-type diverters very inefficient as much of the water either goes down the main gutter or is lost to splashing.
You also need to have an overflow port on your barrels, which is another area where mosquitoes could enter.
First Flush Diverters
With first flush diverters, the rainwater first flows into a vertical section of pipe. A ball in the pipe rises as the pipe fills and blocks it off. Once blocked, the rest of the rainwater flows through a horizontal section of pipe and out to your rain barrels.
First flush diverters are often recommended in places where it rains infrequently because the roof can get very dirty between rains. When it rains, the rainwater which goes through the downspout can be very dirty and then will get cleaner. A first flush diverter keeps this dirty water from making it to your rain barrels.
Despite this, first flush diverters usually aren’t recommended. They have to be cleaned very regularly. If not maintained, they can cause clogs and other failures in your system.
Should Your Downspout Diverter Have a Filter?
You’ll probably want to get a diverter with a filter if:
- You don’t have gutter screens or guards
- There are lots of trees overhanging your roof
- It rains infrequently where you live
- You are capturing large amounts of rainwater which may remain stagnant for long periods of time
- You will use rainwater for showering, hand-washing or drinking
How to Install Downspout Diverters for Rainwater Harvesting
Each downspout diverter is a bit different. However, these are the general instructions you can expect. You’ll need a hole saw or hack saw.
- Determine where you want your rainwater barrels to be
- Set the barrel on a sturdy, level platform
- Mark where the diverter will go on the downspout. It usually needs to be level with or slightly above the barrel inlet.
- Using a saw, cut out a section of the downspout.
- Insert the diverter into the downspout.
- Connect the hose to the diverter and then attach it to the rain barrel.
The images below show how to install the Fiskars DownspoutPro and Earthminded Flexifit downspout diverters.