Gutter Leak: Causes & How to Fix a Gutter Leak

leaking gutter

Gutter Leak vs Gutter Overflow

A gutter leak us when water drips, seeps, or leaks out of the gutter system anywhere other than from the downspout. However, leaking gutters are often confused with overflowing gutters. Gutter overflow is when the water goes over the tops of the gutters or behind the gutters. Whereas gutter leaks are when the water drips, leaks, or seeps from the undersides of the gutters. 

From how to identify the issue to how to fix a gutter leak, the gutter experts at My Gutter Pro will tell you everything you need to know about leaking gutters. 

Types of Gutter Leak

There are only a few locations that the gutter system could possibly leak water from. Places like the seams and corners are the most common. If you are able to observe the leak in gutter systems, like when it is raining, you’ll be able to determine what is causing the problem. Or at least you will have it narrowed down to 2 or 3 possibilities.

1. Gutter Corner Leak or Gutter Mitter Leak

outside miter leak

The most common place that you will see a gutter leak are the miters. Gutter Miters are the corner joints that take the water around a corner to another gutter section. Without miters the gutters would be separate from each other and every gutter would need it’s own downspout. A good way to think of a gutter miter is a corner joint.

A gutter corner leak can happen for a few reasons. 

The first thing people think is that the seal has broken and the miter need new gutter sealer. While this is often true there are actually a couple other possibilities that could cause this. Such as clogged downspouts. 

When the downspout is clogged the water can not drain and eventually it begins to fill up the gutter. That water must go somewhere so it will escape from any seams it can find like the miter seams. Be sure to verify that your downspouts are not clogged before re-sealing the miter.

The most common reason for miter leaks (assuming they are sealed properly) is when the gutter pitch is off. When the pitch of the gutters is off the water is not able to flow properly towards the downspout. This will cause water to sit in the gutters. It is frequent for the water to pool in the corners. This water eats the seals away in the miters.

In the short video clip below we show how water slowly drips from under the miter seam. You may also notice an icicle that has formed here. This is a good indication that the miter is leaking. However you can’t rule out all icicles as signs of gutter leak. If there is enough snow and ice accumulation all gutters will have icicle hanging from them.

Not only should you fix your gutter pitch, you might also need to reapply gutter sealer on the miter.

2. Gutter Seam Leak

gutter leak

When we say gutter seam we are only referring to an actual gutter seam where two gutter sections meet. Some people will confuse the seam created by a miter the seam, or we’ve even hear where the gutter and downspout meet referred to as the seam.

Two sections of gutter are joined together sometimes for whatever reason and the seam is sealed over will a gutter sealant or caulk. Over time the sealant eats away, causing the gutter leak. It all depends on how much water hits the seal, if it drains, etc.. Regardless of the cause, if water is leaking from an area where to gutters are joined, then likely the gutter seam needs to be cleaned and re-sealed.

3. Gutter End Cap Leak

On the left end and right end of every gutter is either a miter of an end cap. Miters are for going around corners whereas end caps are for ending the gutter run. It is easy to identify a gutter end cap because it is the end of the gutter. Therefore it is also easy to identify a gutter end cap leak because the water will be leaking from the end of the gutter.

Almost every time you see an end cap leak it is directly related to the gutter pitch being off. When the gutter is tilted in the wrong direction, the only place for the water to go is through the the gutter end cap seal.

back pitched gutter


The pitch of this gutter causes the water to damage the end cap seal.

4. Downspout Leak

Downspout Connection

gutter downspout leak

The place where the downspout meets the gutter is called the gutter outlet. It is basically a circular outlet that is installed to the gutter that the downspout then attaches to. Water leaks from this area pretty much mean one thing , and that is that the downspout is clogged. Nothing else causes water to leak from this area.

Downspout Seams

gutter downspout seam

Two or three story homes require downspout runs to be 20 to 30 ft. plus. Since downspouts only come in 10 ft. sticks they need to be seamed together. The connection point of two sticks of downspout is called the downspout seam. Much like the gutter outlet connection or seam, there is only one cause of this. And this is a clogged downspout. If you see water leaking from you downspout seams it is a direct indication of clogged downspouts.

5. Gutter Rust

gutter rust

Water will leak through any hole that it can find in the gutter system. Whether the hole is from damage, rust, or corrosion the result is always the same. You are left with the decision to attempt to seal the hole with a waterproof sealant, or to replace the section that is leaking. The problem with sealing up rust holes is that sealant does not stop the rust from spreading. Once aluminum gutters have started to rust there really is no stopping it. It permeates the metal and destroys it from the inside. CLICK HERE for more information on Gutter Rust.

6. Water Leaking Behind Gutter

If you observe water coming from behind the gutter, that is could be caused from a couple different issues. We always go through the check list to cancel out any possibilities and narrow it down. With this type of gutter leak, the first thing you want to makes sure is that the gutters and downspouts are clear of debris. Clogged gutters and/or downspouts can cause the water to go over or behind the gutter. Next we would rule out loose gutters and then gutter pitch. They both can cause water to go behind the gutter. Lastly we would look towards issues with the flashing or drip edge.

Water going behind the gutter can be a serious issue and should be looked into more seriously or promptly then most other gutter issues. Wood damage is likely occurring if water is going behind the gutters.

CLICK HERE to visit My Gutter Pro’s new blog spot “Talking Gutters” where we give away all the information you will ever need about gutters.

My Gutter Pro

93 Monocacy Blvd. A-6

Frederick, MD 21701

(973) 852-6987

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