Why Water is Leaking Through Your Sliding Glass Door and How to Stop It

Water leaking through a sliding glass door isn’t a new issue. Leaking sliding glass doors can result from something simple, like dirt buildup, improper installation, or damage, requiring the aid of a repair specialist. Combine these issues with a pelting rainstorm, tornado, or hurricane, and you have a recipe for a flooded patio door track, small water leaks around the frame, and water damage in your home. 

Try not to fret—sliding patio doors may be finicky, but there’s often an easy fix if there’s leaking. Here’s how you can identify the common issues, what to do about them, and who to call for a professional fix.

How to Locate the Leak

Let's say you come home from a long day of work, and there's a pool of water just inside your sliding door. You're not sure where it came from either—was it a leaky window? The track of the door? Or was it even around the top frame?

If it’s not currently raining and you want to stop further leaks in the future, break out the garden hose. Lightly spray the outside of your door and observe where the water breaks through to the inside. If a light mist doesn't do it, add some water to the track. The bottom track is the most common culprit, but it's important to rule out other areas first.

How to Identify the Cause of Your Sliding Door Leak

A leak's pooling point and travel path can clue you into what's causing the problem. Before water pools near your feet, it usually leaves behind a wet trail. Use the following to help you trace the origin.

Wait for a rain shower to observe the water's path in real time. If you never seem to be home when it rains, simply use a hose to lightly spray the door from the outside to watch the water's path of travel in real time. If necessary, deposit water directly on the bottom track if you suspect that a broken track is the culprit.

1. The Door Was Installed Incorrectly 

If your patio door was installed recently and you notice water pooling around the bottom of your door, it’s possible that the threshold or sill pan was installed incorrectly. If water is coming in through the side of your patio door, you might need additional caulking or reinstalled flashing. When hiring a contractor for your patio door, make sure to find a local door installer that comes with references and a good online reputation.

How to Fix It

Depending on the issue, you’ll likely need to have parts of your door, or the entire door, reinstalled. Contact sliding glass door companies nearby to assess the situation.

2. The Track Is Dirty

Dirty shoes, muddy paws, and gusts of wind all carry grit, dirt, stones, and everything in between into the tracks of our door. These small particles can build up over time, slowly breaking the seal between the bottom of your sliding door track and the door itself.

Even the smallest separation or misalignment can lead to water intrusion and even lower its security.

How to Fix It

It’s time to grab your vacuum and clean the sliding doors. Try to remove as much visible frit from the door track as you can. If possible, vacuum around the edge of the stationary door as well. You can also use a simple solution of dish soap and water with a wire brush to break up the remaining grit.

3. The Track or Rollers Are Broken

Do you find yourself dragging the door along its track, especially in one tricky spot that always seems to catch? You may have a broken or dented track breaking the seal with your door and letting water in.

The rollers—which move your door along the track—can also wear over time, further causing the door to drift off its track and cause a leak.

How to Fix It

The easiest route is to call sliding glass door companies in your area to have them examine the track and rollers. Replacing the rollers or track yourself will cost between $20 and $100, while hiring a pro will cost an extra $75 to $140.

4. Your Weep Holes Are Blocked

Many sliding doors come with built-in protection against misdirected rain. Even if your door is properly installed, rain still naturally blows into the track. Weep holes are actually small slats that allow water to drain from the base of the track without being big enough to let in bugs.

However, these slats can easily become clogged during installation—often with caulking—or clogged from debris.

How to Fix It

Look up the model number of your sliding door to find details about where your weep holes are located. Check if paint, caulking, or other debris block the water flow and remove it on your own or with the help of a contractor.

5. The Door Flashing Is Broken

The base of your door should have a line of metal flashing that redirects water away from your house. This is particularly necessary if your door sits flush with the ground or patio and water frequently flows past the base. If this flashing becomes dented, it could have trouble draining the water.

You should also have the door flashing above the frame, which acts the same way. If it's improperly installed or bumped by a tree branch at some point, it could send water up against the side of your home and eventually through the frame.

How to Fix It

It's best to bring in a sliding door specialist to install or replace your door flashing. The piece requires very specific placement, and you may need to adjust surrounding parts to remove or place it.

6. The Glass Is Unsealed

If the hose test sends water creeping through the top or side of your windowpane—instead of around the frame—there's a chance the glass has come unsealed. This can happen over time, after severe weather damage, or even when it is installed improperly.

How to Fix It

If you recently had the door installed, double-check your warranty for repair requests. If not, call a local glass repair specialist to take a look.

7. You Need Weatherstripping

If you're experiencing leaks in the colder months, especially after a snowstorm, adding new weatherstripping can help reinforce your doors. Weatherstripping often only consists of a thick foam tape or a rubber tube that latches onto the bottom of the door.

How to Fix It

Adding new weatherstripping yourself should only cost between $30 and $100. Calling in a professional to tackle the project will add about $150 for the labor.

8. There’s Wood Rot Around the Door

Rotted wood in the door frame or siding can happen because of prolonged exposure to moisture, leading to decay. One of the tell-tale signs of this problem is water stains or visible deterioration on the siding, which may appear as discolored patches or areas where paint has peeled off. 

How to Fix It

You might not be able to perceive the extent of the damage, which is why it’s best to have a professional come inspect it. They’ll need to remove the rotted wood, install new siding material, and properly seal any gaps or joints. 

When to Call a Pro

Smaller leaks caused by clogs, dirt buildup, or parts that you can easily replace likely won’t need a pro to come fix them. But, in some cases, professional help may be necessary, and it’s best to get the leak fixed as soon as possible to prevent mold growth, structural deterioration, and higher repair costs down the line.

Here are some questions to help you decide if you need a pro:

• Is the leak widespread, affecting multiple parts of the door?

• Have your previous DIY attempts to fix the leak been unsuccessful?

• Is there visible damage to the door frame, walls, or flooring?

• Do you have the tools or experience to repair it yourself?

Local water cleanup professionals can also help you both move more quickly and allow you to avoid potentially dangerous water hazards. Handling the damage after the fact may require hardwood floor repair or more extensive water damage restoration services.