You weren’t expecting to add “investigate mysterious puddle” to your summer to-do list, but here we are.
If you’ve noticed water around your air conditioner, don’t panic. While an AC leak should never be ignored, it doesn’t automatically mean your system is done for. In many cases, the cause is something relatively straightforward and fixable.
Let’s take a look at what might be causing the leak, what you can safely check yourself, and when it’s time to call in the experts.
First Things First: Turn Your AC Off
If water is actively pooling around your system, switch your air conditioner off.
This helps prevent additional water damage and gives you a chance to investigate safely. It can also prevent further strain on the system if the leak is related to a frozen coil or airflow issue.
Now that the emergency has been downgraded from “panic” to “mild annoyance,” let’s look at some common causes.
Why Is My Air Conditioner Leaking?
Believe it or not, your air conditioner is supposed to create water.
As your system cools your home, it removes humidity from the air. That moisture turns into condensation and is normally carried away through a drain system. When something interrupts that process, water can end up where it shouldn’t.
1. Your Condensate Drain Line Is Clogged
This is one of the most common causes of an AC leak.
Over time, dust, dirt, algae, and debris can build up inside the drain line. When the blockage becomes severe enough, the water has nowhere to go and starts backing up into your home instead.
Think of it like a clogged sink. The water isn’t the problem. The blocked pathway is.
2. Your Air Filter Is Long Overdue for Retirement
We know.
Changing furnace filters isn’t exactly at the top of anyone’s list of exciting weekend activities.
But a dirty filter restricts airflow, which can cause the evaporator coil to become too cold and freeze. When that ice eventually melts, the excess water can overwhelm the drain system and create a leak.
If you can’t remember the last time you changed your filter, this is a great place to start.
3. Your Evaporator Coil Has Frozen
Frozen coils often go hand-in-hand with airflow issues, dirty filters, or low refrigerant levels.
When the ice melts, it can create more water than the drain pan can handle, resulting in puddles around your equipment.
You may also notice:
- Reduced cooling performance
- Ice on refrigerant lines
- Weak airflow from vents
- Higher indoor humidity
If you spot ice anywhere on your system, turn it off and allow it to thaw before scheduling service.
4. Your Drain Pan Has Seen Better Days
Like many things in life, drain pans don’t last forever.
Over time, older pans can rust, crack, or develop holes. Instead of collecting condensation and directing it away safely, they allow water to escape underneath the system.
The good news? This is typically a repairable issue when caught early.
5. There Could Be a Refrigerant Problem
Low refrigerant can cause pressure changes within the system that lead to frozen coils and subsequent water leaks. Unlike changing a filter, this is not a DIY fix. Refrigerant issues should always be diagnosed and repaired by a licensed HVAC technician.
What Can I Safely Check Myself?
Before booking a service call, there are a few simple things homeowners can inspect:
✓ Check your air filter
✓ Look for visible ice on refrigerant lines or coils
✓ Check for standing water around the indoor unit
✓ Make sure your thermostat is set correctly
✓ Ensure your system has adequate airflow around vents and returns
If you find a dirty filter, replacing it may solve the issue before it becomes a larger repair.
When Should I Call a Professional?
If the leak continues after changing the filter, if you notice ice buildup, or if water is causing damage to surrounding flooring, drywall, or equipment, it’s time to bring in an expert.
Air conditioners are complex systems, and while some causes are minor, others can indicate larger airflow, drainage, or refrigerant problems that require professional diagnosis.
At Harding, our technicians don’t just clean up the symptom. We identify the root cause so the leak doesn’t become a recurring summer tradition.
Because honestly, nobody wants “mopping the furnace room” added to their seasonal maintenance checklist.
The Best Way to Prevent AC Leaks
Routine maintenance.
Annual AC maintenance allows technicians to inspect drain lines, clean components, check refrigerant levels, verify airflow, and catch small issues before they become expensive repairs. Regular maintenance also helps improve reliability, efficiency, and overall comfort throughout the cooling season.
Need Help With a Leaking Air Conditioner?
If your AC is leaking, don’t wait for a small puddle to become a big problem.
The Harding team has been helping Ottawa homeowners stay cool and comfortable since 1994. Whether it’s a clogged drain line, frozen coil, or something more complex, we’re here to help get your system back to doing what it does best: keeping you cool without turning your basement into a splash pad.
