BACKJAN 31, 2026
Discovering dampness, peeling paint, or warped wood around a window is a common issue for homeowners, and it’s right to take it seriously. Water that gets where it doesn’t belong can lead to more significant problems like wood rot, mold, and damage to your walls.
Looking for more guidance? Take a look at our Repairs overview.
The good news is that you’ve caught it, and figuring out the source is usually straightforward. Most window leaks come from one of two places: rainwater getting in from the outside or condensation forming on the inside.
This guide will help you calmly diagnose the problem, walk you through some simple repairs you can likely handle yourself, and clarify when it’s best to call a professional for help.
Before you can fix the problem, you need to determine where the water is coming from. Let's start with a simple investigation.
Grab a flashlight, even during the day, as it can help highlight moisture and water stains.
Once you have a better idea of the timing, you can move on to the right solution.
If water only shows up after precipitation, the seals protecting your home from the outdoors have likely failed. The fix depends on your window frame’s material.
On vinyl or metal windows, the most common failure point is the exterior caulk. Over time, caulk can dry out, crack, and pull away from the frame, creating a path for water.
When it’s safe to try yourself:
If the metal flashing (the L-shaped metal strips that direct water away from the top of the window) appears intact and the window frame feels solid, re-caulking is a simple and effective DIY repair.
How to Re-Caulk a Window:
Wood frames can be vulnerable to rot if their paint seal is compromised. A small area of soft wood can often be repaired without replacing the entire window.
How to Check for Wood Rot:
Use a screwdriver or an awl to gently poke the areas that look damaged or discolored. If the wood feels soft and spongy or crumbles easily, you’re dealing with rot.
When it’s safe to try yourself:
If the rotted section is small (less than the size of a quarter), shallow, and not in a critical structural part of the frame, you can usually repair it with epoxy wood filler.
How to Patch Minor Wood Rot:
While some window leak repairs are great for a homeowner to tackle, others require an expert eye and specialized tools.
It’s time to call a window repair specialist if:
If the water damage is not related to rain and you don’t see moisture trapped between the glass panes, the problem is likely excess humidity inside your home. When warm, moist indoor air hits a cold window pane, the water vapor condenses into liquid.
You can often solve this by simply reducing indoor humidity:
Fixing minor window water damage yourself is one of the most affordable home repairs.
Keeping a log of your home’s condition, like noting when you last sealed your windows, can be a great help. The Casa app is an easy way to track these small but important maintenance tasks.
Finding water damage is stressful, but by working through these steps, you can identify the source and decide on the best path forward. Many window leaks are minor issues that you can resolve with a little time and effort, preventing bigger headaches down the road.
And for everything else, Casa is here to help. Download the app to manage your home maintenance, keep track of repairs, and get clear, confident advice whenever you need it.
