Why Is My Air Conditioner Leaking Water?

You walk past your indoor AC unit and—uh oh—there's a puddle forming underneath. What gives?

If your air conditioner is leaking water, it’s not just an annoying inconvenience. It could be a red flag that your system needs urgent attention. At Eco Pro Heating, we’ve seen it all, and we’re here to help you get ahead of the problem before it turns into water damage, mould, or costly repairs.

Here’s a no-fluff breakdown of why it’s happening—and what you should do about it.

why is my air conditioner leaking water​

Why Do Air Conditioners Leak Water in the First Place?

Let’s start with the basics. Your air conditioner naturally produces condensation as it cools your home. That water should drain safely through a line that runs from the indoor unit to the outside. When everything is working correctly, you’ll never notice a thing.

But if there’s a clog, crack, or coil issue, that moisture has nowhere to go—and starts pooling around the unit instead.

Is a Small Leak Normal?

A tiny bit of water on a hot, humid day isn’t unusual. But:

  • If it’s leaking when the unit is off
  • If there’s standing water that doesn’t dry quickly, or
  • If you see frequent dripping from the indoor unit

…it’s time to take action.

why is my air conditioner leaking water​

Common Causes of an AC Leak (And How to Fix Them)

1. Clogged Condensate Drain Line

Over time, dirt, dust, and even mold can build up in the AC drain line. Once that line clogs, water backs up into the unit and spills out.

Fix it: Try using a wet/dry vacuum to suck out the blockage. If that doesn’t work, call in a pro to flush the line.

Schedule an HVAC diagnostic visit

2. Dirty Air Filter

Restricted airflow can cause the evaporator coil to freeze. When it melts, it can overwhelm the drain pan and cause leaking.

Fix it: Change your filter every 1–3 months. If your AC has already started leaking, swap the filter and call us to check the coil.

See our AC maintenance services

3. Low Refrigerant Levels

Low refrigerant can cause the coil to get too cold and freeze. When it thaws, excess water flows into the drain pan.

Fix it: This isn’t a DIY job. You’ll need a licensed HVAC technician to check refrigerant pressure and recharge the system if necessary.Book a refrigerant inspection

4. Cracked or Rusted Drain Pan

Your AC's drain pan is designed to collect water, but over time, it can crack or rust through—especially in older units.

Fix it: Small cracks can be patched temporarily, but we recommend replacing the pan entirely to prevent repeat issues.

Get a HVAC quote for AC part replacement

5. Frozen Evaporator Coil

If the evaporator coil is dirty or airflow is blocked, it can freeze over. When it melts, it may leak excessively.

Fix it: Replace your filter, check refrigerant, and have a technician clean the coil. Prevent future buildup with routine service.

why is my air conditioner leaking water​

What NOT to Do When You See a Leak

  • Don’t keep the AC running while it’s leaking.
  • Don’t ignore standing water near your unit.
  • Don’t assume it’ll fix itself—it won’t.

Instead:

Turn off the unit.

Clean up the water.

Call a qualified technician.

When to Call an HVAC Professional

If you’ve checked your filter and tried clearing the drain line but still see water, it’s time to get help. A trained Eco Pro Heating and Cooling technician can inspect your system, identify the cause, and fix it quickly—before you’re stuck with drywall damage or mould issues.

We’ve helped over 42,000 homeowners across Vancouver and the Sunshine Coast stay dry and comfortable with expert HVAC service.

Book your leak inspection today

why is my air conditioner leaking water​

Q&A: AC Leaks

Can I run my AC while it’s leaking?
It’s best to turn it off to prevent more water from damaging your home.

How much water leakage is normal?
A few drops of condensation during operation is fine. Large puddles or leaks when the AC is off are not.

Can I fix a clogged drain line myself?
You can try a wet/dry vacuum or cleaning tool, but heavy buildup or mold will likely require a professional.

Could this be a sign I need a new AC?
If your system is over 10 years old and leaking frequently, it might be time for an upgrade. We’ll give you honest advice either way.

Ready to Fix Your Leaking AC?

Water should never be part of your cooling system. Whether you need a quick repair, part replacement, or an honest second opinion, Eco Pro Heating is here to help. With 20+ years of experience and a track record of over 42,000 satisfied customers, we’ve seen—and solved—it all.

We offer on-site assessments, transparent quotes, and 3-year extended warranties on all AC repairs and installations.

Book your free HVAC estimate today

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Your comfort is our craft. Let’s fix that leak—for good.