Why Is My Condo AC Leaking Water in Fall or Winter? Toronto Residents’ Guide

Many Toronto residents see water leaks from their condo AC or fan coil unit even in fall and winter. Learn the common causes, risks, and solutions for off-season AC leaks in Toronto condos.

Hudson HVAC
October 8, 2025
5 min read

Why Is My Condo AC Leaking Water in Fall or Winter? Toronto Residents’ Guide

Introduction: The Off-Season AC Leak Problem

For most Toronto condo residents, air conditioning feels like a summer-only issue. By October, the building usually switches from cooling to heating mode, and AC units are rarely turned on again until the following May.

So why do so many Toronto residents still see water leaking from their condo AC or fan coil units in the fall and winter months?

The truth is that AC systems — especially fan coil units and water-source heat pumps common in Toronto high-rises — continue to run air movement even when they’re not actively cooling. Condensation, clogged drains, and leftover summer issues can still cause leaks long after cooling season ends.

Why Leaks Happen in Fall and Winter

1. Residual Summer Moisture

After a humid Toronto summer, condensate pans and drain lines may still be wet or clogged. Even when the building switches to heat, that trapped water can leak into your suite weeks later.

2. Clogged or Dirty Drain Lines

In fall, when residents aren’t checking their units as often, clogs from dust, dirt, or algae buildup can cause water to back up unexpectedly.
Since cooler weather means you aren’t expecting condensation, these leaks often go unnoticed until damage is done.

3. Rusted or Damaged Drain Pans

Many downtown Toronto condos (CityPlace, Bay Street corridor, Liberty Village) have fan coils 15–20 years old. Rusted drain pans leak even when minimal water is present, and the issue persists year-round.

4. Frozen or Condensing Pipes Near Windows

In winter, the temperature difference between warm indoor air and cold exterior walls can cause condensation on supply pipes connected to fan coils. This isn’t cooling-related but still leads to leaks.

5. Heat Pump Issues

For buildings with water-source heat pumps, leaks can occur even in heating season due to:
- Cracked drain hoses
- Improper sealing
- Ongoing condensation inside the cabinet

Toronto-Specific Risks of Off-Season AC Leaks

In a high-rise condo, water always finds its way downwards. Whether in July or December, the risks are the same:

Damage to your unit: Floors, drywall, and baseboards absorb water quickly.
Damage to neighbors’ units: A drip in your suite can mean a ceiling leak two floors below.
Insurance complications: Toronto condo declarations typically make residents responsible for their in-suite equipment year-round. Even if you aren’t using the AC, you can still be liable.
Mold growth: Cold weather and closed windows mean leaks can go unnoticed, creating hidden mold problems.

Resident Responsibility vs. Condo Management in Winter

A frequent Toronto question:
“If my AC leaks in winter, do I still have to fix it, or is it the condo board’s problem?”

In most Toronto condominiums:

In-suite fan coils or heat pumps = Resident responsibility.
Building risers and common systems = Condo corporation responsibility.

That means if a rusted drain pan or clogged filter causes a leak in your unit in November, you’ll likely be responsible — even if you weren’t actively using the AC.

What Toronto Residents Should Do If They Spot a Leak in Fall/Winter

Step 1: Turn Off Your Unit

Even in heating mode, switch the fan off to stop air movement and slow the leak.

Step 2: Check for Obvious Causes

Dirty filter? Replace it.
Visible standing water in the drain pan? Clean it out if safe.

Step 3: Document the Leak

Toronto condo boards often require photo or video evidence to determine responsibility.

Step 4: Notify Management

Even in the off-season, water damage is a building-wide concern. Alert your property manager immediately.

Step 5: Book a Professional Inspection

A Toronto condo HVAC specialist can clean your drain lines, inspect your pan, and prepare your system for next cooling season — preventing repeat problems.

Preventing Condo AC Leaks in Toronto During the Off-Season

The best way to avoid winter water surprises is preventive maintenance in the fall. Hudson HVAC recommends:

Seasonal fan coil or heat pump inspections (before winter shutdown)
Drain pan and line cleaning to remove summer buildup
Filter replacements every 3–4 months, even when AC isn’t in use
Checking insulation around pipes to prevent condensation near windows
Proactive replacement of aging fan coils (common in Toronto condos built 2000–2010)

Many downtown Toronto condo boards now require proof of annual maintenance, not just summer service, to avoid insurance disputes when leaks occur in winter.

Real Examples from Toronto Condos

Downtown (CityPlace & ICE Condos): Many residents report winter leaks from original fan coils that rusted through after 10+ years of use.
Midtown (Yonge & Eglinton): Fall drain clogs are common, with water backing up weeks after cooling season ends.
North York: Heat pump leaks remain an issue year-round, especially in buildings that don’t mandate seasonal service.

Why Fall/Winter Service Matters

In Toronto, most residents only think about AC once summer hits. But the truth is, winter leaks can be even more damaging, because:

Residents aren’t looking for them.
Windows are closed, so humidity lingers.
Detection often happens late, after water has spread.

By scheduling fall maintenance, you protect your suite, your neighbors, and your wallet.

Conclusion: Stop Leaks Before They Start

If your condo AC or fan coil is leaking water in fall or winter, don’t ignore it. In Toronto’s high-density condo environment, even a small drip can escalate into multi-unit water damage and costly disputes.

Know the causes — from clogged drains to rusted pans.
Take action quickly — shut down your unit, document the leak, and notify management.
Invest in preventive care — seasonal inspections keep Toronto condos dry and stress-free.

Contact Hudson Condominium Solutions today to schedule your fall/winter condo HVAC inspection. Protect your suite, your building, and your peace of mind before the next cooling season arrives.