Items that Cause Plugged or Clogged Downspouts
What Causes Plugged Downspouts?
There are many items around a house that plug downspouts. By knowing the most common ones, you can take action to keep your downspouts from being plugged.
First, recognize that a plug is something that blocks the entrance to a downspout. A clog is a blockage inside a downspout. Plugs are easily remedied by clearing the downspout entrance where it meets the gutter. A downspout clog is cleared with a plumbing snake and water. Sometimes a disassembly of the downspout is required.
Most people know they have plugged or clogged downspouts when water overflows the gutters onto the barkdust or walkway below. Even if the gutters have been recently cleaned, gutters can overflow from plugged downspouts.
Leaves Plug Downspouts
Leave are by far the most common plugger of downspouts. They are nice and curly when they fall into the gutter, but then rain and moisture softens them into flat flexible pancakes. They then wash down towards the downspout and effectively seal it off. The solution to this is downspout strainers (various types) and gutter filters or gutter guards. Also, cutting back tree limbs helps. There should not be any tree branches directly over the roof.
Needles
More about needles to go here
Twigs Jam downspouts
Twigs that are longer than a downspout is wide may jam at the opening or first bend in the downpout's elbow. This further blocks the opening, allowing even smaller material to plug or clog the downspout.
Roofing Material Seal off downspouts
If you've had your roof worked on recently, the roofer may have left debris on the roof or in the gutter. Pieces of composition roof, 3 tab, roofing nails, splinters of cedar shake etc migrates towards the downspout and plugs it off. Check with your roofer as they are cleaning up to make sure they remove any debris that fell into the gutter or is lying on the roof. Downspout strainers and gutter filters and gutter guards help also.
Nuts From Squirrels Clog Downspouts
Squirrels themselves don't usually plug downspouts, but if they have access to your roof, they drop nuts and nut shells into the gutters which float their way to the downspouts. The nut shells are often large enough to make a blockage, especially walnut halves. One solution to this is to install downspout strainers. Another solution is gutter filters or gutter guards.
 Squirrels drop things into gutters that plug downspouts
Raccoons
Raccoons can get access to your roof through stout branches from neighboring trees. Raccoons may leave poop on your roof that washes down into the gutters and may plug the downspouts. This is very gross. A solution to this is to remove neighboring branches and trees. Another solution is to install slippery metal flashing around the tree trunk which keeps the raccoon from being able to climb the tree.
 Raccoon in a tree with stout branches
Shoes, Sandals and Flip-Flops Seal Off Downspouts
I don't know why, but flip-flops and shoes are found in gutters. A solution to this is don't throw them up there. I think it's because kids get to playing etc cannot get up there to remove it and then don't want to tell their parents :)
Toys Clog Downspouts and Drains
Toys are also found in gutters. This includes tennis balls, shuttles and plastic figures. Encourage your kids (and spouse) to let you know soon after a toy is lost in the gutter so that it can be removed before it causes the gutter to overflow in a rain. It's easier to remove in nice weather than during a downpour.
 A shuttlecock from a badminton game laying in the gutter.
The Solution To Plugged and Clogged Downspouts
There are several solutions to plugged downspouts. Each solution listed below should be chosen according to your situation and needs. More than one solution can be used.
Enlarged downspouts
Downspout Strainers
Enlarged Downspout Openings |