Why Is Water Leaking Around My Window?
The good news is that this is usually the cheapest category of window problem — and frequently no glass needs replacing at all.
Water appearing at a window during rain is almost always a sealant, gasket or weep hole failure rather than a glass problem. Windows are designed to manage water, not exclude it entirely: rain that gets past the outer seal is meant to drain out through small weep holes at the sill. When those block, or perimeter sealant cracks, the water finds its way inside instead.
This matters financially, because a company that diagnoses it as a glass problem will quote a replacement you do not need. A meaningful share of these calls end with no glass being replaced at all.
- Usual cause
- Sealant, gasket or blocked weep holes
- Is it a glass problem?
- Usually not
- First thing to check
- Weep holes at the outside of the sill
- Why act quickly
- Water in a wall causes rot and mould
Windows Manage Water, They Don't Block It
This surprises most homeowners. A modern window is not designed as a watertight barrier. It is designed on the assumption that some rain will get past the outer face, particularly in wind-driven conditions, and that the water must then be given a controlled path back outside.
That path runs down the inside of the frame to a channel at the sill, and out through small openings called weep holes on the exterior face. As long as that route is clear, the system works invisibly for decades and you never know it is happening.
Block the route and the channel fills. Once it overflows the interior lip, water appears on your sill and you have what looks like a leak. Nine times out of ten nothing is broken — the drainage has simply stopped draining.
Working Out Where It Is Actually Coming From
| Symptom | Most Likely Source |
|---|---|
| Water pooling on the interior sill after heavy rain | Blocked weep holes. The sill channel is filling and overflowing inward. |
| Water only during wind-driven rain from one direction | Perimeter sealant failure on that elevation, letting water in behind the frame. |
| Damp or staining on the wall below the window | Water getting behind the frame rather than through it. More serious, and worth acting on quickly. |
| Water running down the inside of the glass | Often condensation rather than a leak, especially in winter. Check whether it correlates with rain or with cold. |
| Draft plus water at the same spot | Failed or compressed gasket. The seal is no longer making contact along that run. |
| Leak appeared after a recent installation | Perimeter flashing or sealing at the wall opening. This is an installation defect, not a maintenance issue. |
| Water at a corner specifically | Corner joint failure in the frame or the sealant. Corners are where movement concentrates. |
The single most useful thing you can do before calling anyone is to find the weep holes. They are small slots or holes on the outside face of the sill, usually with a flap or baffle. Check whether they are blocked with dirt, paint, insect nests or caulk — and it is remarkably common to find that someone has sealed them shut, believing they were a defect.
Why This Is Worth Dealing With Promptly
Water on a sill looks minor and is easy to keep wiping up. What makes it worth attention is where the water goes when it is not appearing on the sill: into the wall cavity, the framing and the insulation below the opening.
In a DFW climate that means rot in timber framing, corroded fixings, ruined insulation and, given our humidity, mould. None of it is visible until the repair becomes structural, at which point you are into carpentry and drywall rather than a sealant and drainage job that might have taken an hour.
A quick way to distinguish a leak from condensation: condensation appears on cold mornings regardless of rain, forms on the room-side face of the glass, and wipes away leaving the glass clear. A leak correlates with rainfall, tends to appear at the sill or frame perimeter rather than across the glass, and often leaves a mineral tidemark.
How We Trace and Fix a Window Leak
Diagnosis first, because the fix is often much smaller than expected.
Trace the Actual Source
We check weep holes, perimeter sealant, gaskets and the frame-to-wall interface before concluding anything about the glass.
Clear the Drainage Path
Blocked weeps are cleared and the sill channel flushed. On a good number of calls, this alone resolves it.
Renew Seals & Gaskets
Failed perimeter sealant is cut out and replaced properly; compressed or missing gaskets are renewed in place.
Confirm and Document
We test the repair and give you an itemized invoice and photographs, useful if a builder, landlord or insurer is involved.
Water Coming in Faster Than You Can Manage?
Broken or displaced glazing during a storm needs securing before anything else. 24/7 emergency service across DFW.
What DFW Property Owners Say
Verified reviews from commercial and residential clients across the Metroplex.
★★★★★Called late night after my front door to my business was broken. They were out to me within 90 minutes to board the door. Had my door as good as new within a week with replacement glass. Good people that do good business. Highly recommend!
Dal Poteat
★★★★★I am a contractor, and I work with this glass shop on a regular basis because I have a lot of clients who want to install custom shower doors. They are the ones that I use for these orders, and they are always on point. I really like the way they do business.
Wayne Castillo
Window Leak Questions
What homeowners ask about water at the window.
Should I just caulk around the window myself?
Be careful, because this is where well-intentioned DIY often makes things worse. Caulking over the exterior sill can seal the weep holes shut, which converts a small drainage problem into a trapped-water problem that damages the frame from inside. If you do caulk, never seal the underside of the sill or any slot on the exterior face — those are drainage, not defects.
Is water on the inside of the glass a leak?
Usually condensation rather than a leak, and the distinction matters. Condensation forms on the room-side surface on cold mornings, appears regardless of rain, and wipes away leaving clear glass. A leak correlates with rainfall, shows up at the sill or frame perimeter, and often leaves a mineral tidemark behind. If it is between the panes, it is neither — that is a failed seal.
Can a leak be fixed without replacing the window?
In the large majority of cases, yes. Clearing weep holes, renewing perimeter sealant and replacing gaskets are all done in place with the window staying exactly where it is. Full replacement only becomes the answer when the frame itself has rotted or the flashing at the wall opening has failed, and the latter is essentially an installation defect rather than a maintenance issue.
The leak started after a new window was installed. Who is responsible?
Almost certainly the installer, and it is worth pursuing rather than paying to fix. A correctly installed window should not leak, and leaks that begin immediately after installation generally trace to flashing or perimeter sealing at the wall opening — which is installation work. Document it with photographs and dates, and go back to them before commissioning anyone else.
How urgent is this really?
More urgent than it looks, because the visible water is not the problem. What matters is water reaching the wall cavity, framing and insulation below the opening, where in our humidity it produces rot and mould without ever being seen. A sealant and drainage repair is inexpensive; the carpentry and drywall work that follows a neglected leak is not.
Could it be the roof or siding rather than the window?
Genuinely possible, and worth keeping in mind. Water travels along framing before it appears, so it can enter well above a window and emerge at the head or sill, making a sound window look guilty. If the window checks out and the leak persists, the investigation should widen to flashing, siding and roof penetrations above the opening rather than continuing at the window.
Get a Window Leak Diagnosed in Your City
We trace leaks to their actual source across the Metroplex — and often fix them without replacing any glass.
Get Your Window Leak Traced Properly
We diagnose before we quote, and a good number of these calls end without any glass being replaced at all.
Window Leak Diagnosis and Repair in Dallas-Fort Worth
Blade Glazing LLC diagnoses and repairs window leaks throughout the Dallas-Fort Worth Metroplex, including Arlington, Dallas, Fort Worth, Frisco, Garland, Grand Prairie, Irving, McKinney and Plano. Water appearing at an interior sill during rain is most commonly caused by blocked weep holes, failed perimeter sealant or compressed and missing gaskets rather than by any fault in the glass. Windows are designed to drain water that passes the outer seal through weep openings at the sill, and blocking those openings — often inadvertently, by caulking over them — is a frequent cause of apparent leaks.
Services include leak source tracing, weep hole clearing and sill channel flushing, perimeter sealant renewal, gasket and weatherstripping replacement, glazing bead re-bedding, failed insulated unit replacement and photographic documentation for insurance, landlord and builder claims. Blade Glazing is a family-owned company serving Texas since 2016 with OSHA-certified technicians, free estimates and BBB accreditation.
Blade Glazing LLC · 1504 South I-35E #250, Lancaster, TX 75134 · (214) 687-1216 · Family owned and operated · OSHA-certified technicians · BBB accredited · Serving Dallas-Fort Worth 24 hours a day.