Seattle’s summers aren’t scorching, but when July brings warm afternoons and indoor humidity, more households rely on central air or mini-split AC systems. Unfortunately, air conditioning systems can leak—not from storm damage or burst pipes, but from the one component most homeowners overlook: condensation lines.
Whether you live in a Craftsman-style home in Tacoma, a newer townhouse in Edgewood, or a split-level in Lakewood, a leaking AC unit can silently soak drywall, subfloors, and insulation. This blog explains why HVAC leaks happen, how to spot the signs early, and what to do when you’re faced with unexpected water damage caused by your cooling system.
How Condensation Becomes a Water Hazard
As your air conditioner pulls warm air across its evaporator coil, it naturally collects moisture from the air. That water typically drains away through a condensate line or pan. But if anything blocks that line, or if the system isn’t properly maintained, the moisture backs up—and ends up leaking inside your home.
Common causes of AC water damage include:
- Clogged drain lines from dust, algae, or pet hair
- Dislodged or cracked drain pans
- Poor installation with improper sloping or no shutoff switches
- Frozen evaporator coils that drip excessively when thawing
- Condensation on ducts due to high indoor humidity or insufficient insulation
In many cases, these problems don’t trigger alarms or even affect AC performance right away. Water may be quietly pooling inside walls or ceilings for days before any outward signs appear.
Signs Your AC Is Causing Water Damage
If you’re running your AC regularly in July, especially during humid afternoons, stay alert for:
- Ceiling stains near air registers or attic ducts
- Musty odors coming from vents or nearby walls
- Warped or buckled flooring near indoor air handlers
- Wet spots or soft drywall on lower levels
- Water near the furnace or in mechanical closets
Because many Seattle-area homes have HVAC systems in attics, closets, or crawl spaces, leaks can go undetected longer—making damage more severe and expensive.
Who’s Most at Risk?
In neighborhoods like University Place and Spanaway, where homes often feature forced-air HVAC and sealed attics, condensation issues are common. You may be especially vulnerable if:
- Your system is over 8–10 years old
- You haven’t scheduled AC maintenance this year
- You notice excess indoor humidity during hot spells
- Your air handler is located above finished spaces (ceilings, hallways, etc.)
Mini-split systems aren’t immune either. Improperly routed drain hoses on ductless units can leak directly onto walls, causing slow but serious drywall deterioration.
What to Do When You Discover a Leak
If you find signs of AC-related water damage, act quickly:
- Shut off the AC to stop further condensation
- Inspect the area for active dripping or pooling water
- Take photos of visible damage for insurance purposes
- Call a water damage restoration professional immediately
At 911 Restoration of Seattle, we specialize in pinpointing the cause of HVAC-related moisture, drying affected areas with industrial equipment, and repairing or restoring ceilings, drywall, flooring, and insulation. We’ll even work with your HVAC technician to ensure the root issue is resolved.
How to Prevent HVAC Water Damage
Prevention starts with routine AC maintenance, ideally every spring or early summer. Your technician should:
- Clear the drain line and test for clogs
- Inspect and replace cracked pans or tubing
- Install a float switch that shuts off the system if overflow is detected
- Insulate ducts in humid zones to prevent sweating
- Check system slope to ensure proper drainage
If you live in Tacoma, Edgewood, or surrounding areas, request a restoration-grade inspection of your attic or HVAC closet. It could uncover hidden water damage before it leads to mold or rot.
Don’t Let Your AC Soak Your Home
In Seattle, water damage isn’t always caused by rain. Sometimes, it’s the quiet drip from an overworked AC system that does the most damage.
If you’ve spotted water near your air vents, ceilings, or HVAC system, don’t wait. Contact 911 Restoration of Seattle for fast, local water damage remediation that gets your home—and your cooling system—back on track.
SEO Title: AC Leaks and Water Damage in Seattle Homes
SEO Description: Learn how AC condensation causes water damage in Seattle homes and what to do if your HVAC system leaks.