Water Damage Around Windows: Signs, Causes, and Solutions

Water damage around windows is more than a cosmetic issue—it can indicate ongoing problems that damage your home's structure. According to the EPA, moisture intrusion also creates conditions for mold growth.

Signs of Water Damage

According to FGIA and DOE, watch for:

• **Peeling paint or wallpaper** around window frame
• **Soft or spongy wood** on sill or frame
• **Staining** on walls below window
• **Visible mold or mildew** (often black spots)
• **Musty odor** near window
• **Bubbling or warped drywall**

Where the Water Comes From

According to the U.S. Department of Energy, water intrusion sources include:

Window-Related Causes

• Failed glazing seals letting water behind glass
• Deteriorated frame allowing penetration
• Failed weatherstripping directing water inside
• Condensation from poor-performing windows

Installation/Exterior Causes

• Improper flashing above window
• Failed caulking between frame and siding
• Clogged weep holes (designed to drain water out)
• Ice dams pushing water under roofing

Diagnosis Matters

According to FGIA, before deciding on repairs:

1. Identify the source: Is water entering through the window or around it?
2. Assess extent: Has damage spread to wall framing?
3. Check for mold: According to EPA, mold indicates ongoing moisture

If water is entering around the window (flashing, caulking), the window itself may be fine—only exterior work needed.

If water is entering through the window, replacement is likely needed.

When to Replace

According to DOE, replacement is typically needed when:

• Frame is rotted and structurally compromised
• Damage has spread to surrounding wall
• Water is penetrating through window (not just around it)
• Multiple repair attempts haven't resolved problem

The Bottom Line

Water damage is a symptom—finding the cause determines the solution. According to EPA, address moisture promptly to prevent mold growth and structural damage. Sometimes that means window replacement; sometimes it means exterior repairs.

*For all replacement indicators, see: [Signs Your Windows Need Replacing](/guides/signs-windows-need-replacing)*