First: Turn Off Your AC
Before troubleshooting, turn off your air conditioner at the thermostat to prevent further water damage. Place towels around the leak and move any furniture or electronics away from the water.
It's normal for your AC to produce water—it's a byproduct of removing humidity from your home. But that water should drain safely away, not leak onto your floor. When it does, you need to act fast to prevent water damage and mold growth.
Why Your AC Is Leaking Water
Understanding the cause helps you decide whether you can fix it yourself or need professional help:
Clogged Condensate Drain Line
DIY PossibleThe #1 cause of AC water leaks. Algae, mold, and debris build up in the drain line over time, causing water to back up and overflow.
Fix: Try flushing the line with white vinegar or using a wet/dry vacuum.
Frozen Evaporator Coil
Pro NeededWhen airflow is restricted (dirty filter) or refrigerant is low, the coil freezes. When it thaws, excess water overflows the drain pan.
Fix: Turn off AC and let it thaw. If it refreezes, call for service.
Cracked or Rusted Drain Pan
Pro NeededThe drain pan under your evaporator coil collects condensation. Over time, it can crack, rust, or develop holes.
Fix: The pan needs to be replaced by a professional.
Dirty Air Filter
DIY PossibleA clogged filter restricts airflow over the evaporator coil, causing it to freeze and eventually leak when it thaws.
Fix: Replace your air filter immediately and check monthly.
Step-by-Step Troubleshooting
Step 1: Check and Replace Your Air Filter
A dirty filter is often the root cause of AC water leaks. When the filter is clogged, airflow is restricted, causing the evaporator coil to freeze. When the ice melts, it can overflow the drain pan.
Pull out your filter and hold it up to the light. If you can't see through it, replace it immediately.
Step 2: Inspect the Condensate Drain Line
Find where your AC drain line exits your home (usually a PVC pipe near the outdoor unit). Check if water is dripping out when the AC runs. If not, the line is likely clogged.
To unclog: Try pouring a cup of white vinegar into the drain line access point (usually near the indoor unit). Wait 30 minutes, then flush with water.
Step 3: Check for Ice on the Coil
Open your indoor unit's access panel and look at the evaporator coil. If you see ice, you've found your problem. Turn off the AC and let it thaw completely (this can take 24 hours).
If the coil freezes again after thawing, you likely have low refrigerant from a leak—this requires professional repair.
Step 4: Inspect the Drain Pan
Look under the evaporator coil for the drain pan. Check for cracks, rust holes, or damage. If the pan is damaged, it needs to be replaced by a professional.
Preventing Future AC Water Leaks
Regular maintenance prevents most AC water leak problems:
- Replace air filters every 1-3 months
- Schedule annual AC tune-ups in spring
- Pour vinegar down the drain line quarterly to prevent clogs
- Keep the area around your indoor unit clean and accessible
- Have your drain pan inspected during maintenance visits
- Install a float switch to shut off AC if the drain backs up
When to Call a Professional
Call for professional AC repair if:
- The drain line remains clogged after DIY attempts
- Ice keeps forming on the evaporator coil
- The drain pan is cracked or damaged
- You suspect a refrigerant leak
- The leak has caused significant water damage
- You're not comfortable accessing the indoor unit
Frequently Asked Questions
Why is my AC leaking water inside the house?
The most common causes are a clogged condensate drain line, a frozen evaporator coil that's thawing, a cracked or overflowing drain pan, improper installation, or a dirty air filter restricting airflow. Start by checking your filter and drain line before calling for service.
Is it dangerous if my AC is leaking water?
While the water itself isn't dangerous, the leak can cause significant damage including mold growth, ceiling/floor damage, and electrical hazards if water reaches wiring. Turn off your AC immediately if you notice a leak to prevent further damage.
How do I unclog my AC drain line?
You can try pouring a cup of white vinegar down the drain line or using a wet/dry vacuum to suction out the clog from the outdoor end. For stubborn clogs, a plumber's snake or compressed air may be needed. If these don't work, call a professional.
How much does it cost to fix an AC water leak?
Repair costs depend on the cause. Unclogging a drain line costs $75-$200. Replacing a drain pan costs $150-$400. Fixing a refrigerant leak causing frozen coils can cost $200-$1,500. We provide upfront pricing before any work begins.
Can I run my AC if it's leaking water?
No, you should turn off your AC immediately if it's leaking water inside your home. Running it can cause more water damage, potential electrical hazards, and may damage the AC system itself. Call for professional repair before turning it back on.