Rectangular downspouts come in several sizes, with standard options being: 2” x 3”, 3” x 4”, and 4” x 5”. They are all available in 10-foot lengths and can be connected as needed to lengthen them, as well. Wider downspouts will allow for more water drainage but may also create larger debris issues without proper gutter guards, so consider all the elements in choosing the right size. 

When they are properly installed and maintained, aluminum downspouts can last up to 20 years. Copper downspouts might last 50 years if they are durable and well-maintained, while vinyl downspouts last 10-20 years, depending on the climate. For their durability and lifespan, aluminum downspouts are a popular choice. 

Rectangular downspouts are popular because they go well with the K-style gutter systems and provide efficient drainage. However, round downspouts can typically drain water more effectively than rectangular downspouts. In most climates, the difference is nominal enough that homeowners can choose what they like based on style. 

Rectangular downspouts are corrugated, which makes these two the same thing. The corrugated feature was added to offer support and sturdiness to the gutters while promoting the drainage of water. You can find rectangular downspouts that are not corrugated, but it is less common these days. 

If you need longer downspouts, such as to reach from a second or third-story or larger commercial building, you can connect them. Most styles of downspouts have connectors, elbows, and male and female ends so that they are easy to connect and lengthen when needed. You can find some styles in 20-foot lengths, too, if you prefer the look of a single downspout instead of connected ones.