Why is my air conditioner leaking water?
Air conditioners naturally produce water, that’s the humidity they pull out of your indoor air. Normally it drains away quietly. So when you see water pooling around your indoor unit or dripping from a ceiling, the drainage system has failed somewhere.
Leaks matter because water damages drywall, flooring, and framing, and can breed mould in Metro Vancouver’s damp climate. Acting quickly limits the damage.
HeatLand has served Metro Vancouver and the Fraser Valley since 1999. Here’s what causes AC water leaks, how to protect your home, and when the problem needs a licensed technician.
Where the Water Comes From
As warm, humid air passes over your cold evaporator coil, moisture condenses on the coil just like water beading on a cold glass. That condensate drips into a drain pan beneath the coil and flows out through a condensate drain line, typically a PVC pipe leading outside or to a floor drain. In a healthy system, you’d never notice this water at all. A leak means one part of this drainage path has failed. The most common failure is a clogged drain line: algae, mould, and dust build up inside the pipe over time, especially in our humid climate, until water backs up and overflows the pan. Other failures include a cracked or rusted drain pan that no longer holds water, a drain line that has come loose or disconnected, or a condensate pump (in some setups) that has stopped working. Understanding this path helps you spot where the trouble is, and much of it is accessible for basic checks and clearing.
What to Do Right Now to Prevent Damage
If you find water leaking, act first to protect your home. Turn the AC off at the thermostat to stop producing more condensate. Mop up standing water and place towels or a bucket to catch active dripping, water sitting against drywall or flooring causes damage fast in our climate. Next, if you can safely reach the indoor unit, check the drain pan and drain line. A clogged drain line is the most common cause and sometimes clearable: locate the PVC drain line and, if you have a wet/dry vacuum, you can attempt to suction the clog from the outdoor end of the line. Also check that the drain line hasn’t simply come disconnected. If the pan is cracked or rusted through, it needs replacing by a technician. Don’t ignore even a small leak, because it often signals a growing blockage that will worsen. Safety note: if water has reached electrical components, wiring, or the furnace, do not touch them, shut off power at the breaker and call a professional to avoid electrical shock hazards.
Causes That Need a Technician
Some AC leaks point to problems beyond a simple clog. A frozen evaporator coil that’s thawing produces far more water than the drain can handle, causing overflow; if you find ice along with water, the underlying cause (dirty filter or low refrigerant) must be fixed to stop the leaking for good. Low refrigerant itself both freezes coils and, indirectly, causes leaks, and refrigerant work is regulated and requires a licensed technician. A failed condensate pump, a improperly sloped or installed drain line, or a rusted-through pan all need professional repair or replacement. Persistent leaks despite a clear drain line warrant a full inspection to protect your home from ongoing water and mould damage, a real concern in Metro Vancouver’s humidity. Safety note: standing water near electrical or gas components is hazardous; keep clear and shut off power. HeatLand’s licensed, insured technicians diagnose and repair AC drainage problems across all major brands, and can add preventive measures like drain treatments and float switches that shut the system off before an overflow reaches your ceiling.
Quick Checklist
- Turn the AC off to stop condensate production
- Mop up water and protect flooring and drywall
- Check the drain pan for cracks or overflow
- Look for a clogged or disconnected drain line
- Check for ice signalling a frozen coil
- Keep clear of any water near electrical parts
| Cause | Sign | Fix |
|---|---|---|
| Clogged drain line | Water overflowing the pan | Clear line (DIY) or pro |
| Cracked or rusted pan | Water under the unit | Pan replacement (pro) |
| Frozen coil thawing | Ice plus heavy water | Fix airflow/refrigerant (pro) |
| Disconnected drain | Water at the unit base | Reconnect (DIY or pro) |
| Failed condensate pump | Water backing up | Pump repair (pro) |
Frequently Asked Questions
Is it normal for my AC to leak water?
No. While your AC produces condensate as it removes humidity, that water should drain away unseen. Visible leaking means the drain pan, drain line, or pump has failed, often a clogged drain line. Turn the system off, protect your floors, and clear or repair the drainage path promptly.
Can I fix an AC water leak myself?
Sometimes. A clogged condensate drain line can often be cleared with a wet/dry vacuum from the outdoor end, and a disconnected line can be reconnected. But a cracked pan, failed pump, or frozen coil needs a technician. Never touch components where water has reached electrical wiring.
Why is water dripping from my ceiling below the AC?
A ceiling leak usually means an attic or upper-floor air handler’s drain pan is overflowing, often from a clogged drain line or thawing frozen coil. This can cause serious water damage, so turn the AC off and call a technician quickly. HeatLand serves Metro Vancouver and the Fraser Valley.
How do I prevent my AC from leaking?
Replace filters regularly to prevent coil freezing, and have the condensate drain line cleaned during annual maintenance. Technicians can add drain-line treatments and a float switch that shuts the AC off before an overflow reaches your ceiling. Regular servicing catches drainage issues before they cause damage.
Reviewed by the HeatLand Heating & Cooling team — licensed HVAC contractor serving Metro Vancouver & the Fraser Valley since 1999. This article is for general guidance only. If you smell gas, suspect a carbon monoxide leak, or are unsure about any electrical or gas component, stop troubleshooting immediately and call a licensed technician or 911.