Homeownership comes with many responsibilities and sometimes learning things the hard way.

Some learning experiences are more expensive than others, though, as we realized.

We recently had our AC suddenly leaking water from the top floor onto our main floor, through the ceiling.

And after a costly appointment with a technician, we now know what to do to avoid this from happening again. 

I am sharing this post in the hopes of helping you avoid this costly mistake and potentially pricey repairs on a damaged ceiling or more.

AC Leaking Water From the Ceiling - What To Do

Since we purchased our home, we’ve booked our regular yearly tune-up service appointments for our furnace and the AC. I also clean the AC filters regularly (it is recommended to do this every three months).

But something we didn’t know was that we were supposed to clean and flush the condensate drain line from the AC every year.  

We maintain the AC unit outside and cleaned the filters inside but never flushed the drain line before, this was our problem.

Why is water leaking from the ceiling? 

Warm air blows over the AC’s evaporator coil, and that process forms condensation. The condensation then drips into a drain pan inside the HVAC system unit located inside your house. 

The drain pan collects condensation, and the water is then removed from your home through a condensate drain line. 

If, for some reason, the drain line becomes clogged with dust particles, dirt, sludge, or mould, then the water backs up and ends up overflowing the pan, causing a very messy and inconvenient leak. 

Not all HVAC unit leaks are caused by clogged condensate lines, though you can have a cracked drip pan, clogged air filter, or other issues. So I highly recommend you contact a qualified technician to service your unit if you have an unexpected leak.

We discovered the leak as soon as it started, and it was a slow leak. Since this happened in the evening, we had to pay a premium for emergency service, but we managed to get somebody in to check the HVAC within an hour of the leak starting. 

The technician used a Shop Vac and water to unclog the condensate line and showed us how to clean it.

What to do if your HVAC unit is leaking?

The first thing you have to do is turn the unit off. Call a certified technician to assess and fix the leak.

After the leak has been fixed, use fans and ensure the ceiling and all wet areas are as dry as possible to avoid mould issues.

Depending on the size of the damage, you may need to fix the floor/ceiling, paint, etc.  

We were lucky to fix the issue fast enough not to have extensive water damage.

 After the leak stopped, we used big fans to dry everything properly, and a magic eraser to remove any stains in the paint. 

AC Leaking Water From the Ceiling - What To Do

How to avoid this from happening? 

As part of maintenance, you are supposed to flush the AC drain line with vinegar or bleach every year.

Here are the steps to follow to do this:

  1. Ensure you have turned off your AC system. Turn off the system both at the thermostat and the breaker.
  2. Find the condensate drain line. 
  3. Find the drain line’s access point. 
  4. Flush the AC drain line with vinegar or bleach.
  5. Let it sit for about 30 minutes.
  6. Finish by flushing it with water and see test the AC works properly.

Many YouTube videos available online show you exactly how to do this. Always reference your manual and call a technician if you are not comfortable doing this yourself.

It is also very important to clean or change your filter every 3-months. If the filter clogs, this can lead to a leak as well.

I hope this serves you as a reminder to maintain your AC and HVAC systems, to avoid pricey emergency calls and damage.