Basic gutters aren’t always enough for proper rainwater harvesting. You need to direct water where it needs to go. One of the most overlooked yet crucial components of a well-functioning gutter system is the downspout elbow. Choose the wrong one, and you could end up with water pooling at your foundation, leading to costly damage.
Not sure whether to use an A or B elbow for your downspout? The difference is simple.
A elbows bend forward or backward, while B elbows turn left or right. Choosing the right elbow ensures proper water drainage and prevents foundation damage. Learn how to select the correct size, angle, and placement below.
What is a Downspout Elbow?
A downspout elbow is a bent section of a gutter system designed to redirect rainwater flow. Instead of allowing water to pour straight down from your gutters, elbows guide it along a controlled path, ensuring it reaches a safe drainage area.
Why Are Downspout Elbows Important?
Without properly placed elbows, rainwater can erode landscaping, seep into basements, or damage your home’s foundation. These simple but essential components play a critical role in preventing water-related issues.
How do I know if I need an A or B elbow? We’ll cover that in the next section.
A Elbow vs B Elbow: When to Use Each
When it comes to choosing the right downspout elbow, it all depends on which direction you need the water to flow. Using the wrong type can cause drainage issues, so understanding the difference between A elbows and B elbows is crucial.
A Elbow: Straightforward Drainage
Bends outward or inward when facing the house.
Used at the top or bottom of a downspout.
Directs water straight out into a yard, driveway, or garden.
Best for homeowners who need water to flow directly away from the foundation.
B Elbow: Turning Corners
Turns left or right when facing the house.
Ideal for running a downspout along a wall or around obstacles.
Commonly used when installing downspouts along the side of a house.
Best for homes where water needs to be guided along the structure before being diverted away.
Can I Mix A and B Elbows in the Same Downspout?
Absolutely! Many downspout systems use a combination of A and B elbows to create the most efficient water flow.
A elbows at the top help direct water downward from the gutter.
B elbows at the bottom route water away from the foundation, preventing pooling and erosion.
The key is to ensure that water flows smoothly through the system without restrictions, unnecessary bends, or backflow issues. Proper alignment and secure installation will keep your drainage system working effectively.
What Sizes and Angles Do Gutter Elbows Come In?
Choosing the right size and angle for your gutter elbows is just as important as selecting the correct type. Too small, and your system can’t handle heavy rainfall. Too sharp of an angle, and you risk clogging and flow restrictions.
Common Downspout Sizes
2” x 3” – The standard size for most residential homes.
3” x 4” – Best for homes in high rainfall areas or larger roof surfaces.
Typical Gutter Elbow Angles
30° – A gentle bend, ideal for extending drainage over a long distance.
45° – The standard bend, helping guide water smoothly through turns.
75° – A more pronounced turn, useful in tight spaces.
90° – The sharpest bend, best for areas where space is extremely limited.
How do I measure for the right elbow size?"
Simply measure the width of your existing downspout and match it to an elbow of the same dimensions to ensure a perfect fit and seamless water flow.
Gutter Elbows Matter
We’ve spent nearly two decades perfecting rainwater solutions, so you don’t have to learn the hard way. We offer 90-degree elbows, traditional A- and B-style elbows, downspout diverters, and color-matched options to fit any setup. Plus, our products come pre-crimped, so you can install them correctly without water leaking from the joints—a common mistake we see all too often.
Need a tight turn for a tricky spot? We’ve got true 90-degree elbows that hug the wall.
Installing a rain barrel? Grab an offset downspout diverter that includes the correct elbow.
Want a clean, professional look? Choose from our color-block selection to match your existing gutters.
Don’t wait until your gutters are overflowing or your basement is damp— take control of your drainage system today. Browse our full selection of downspout elbows and accessories at AquaBarrel and get the right fit for your home. Because when it comes to rainwater, planning ahead always beats cleaning up after.