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HVAC expert | Published: November 29, 2022 Update on: November 20, 2025

Is Furnace Leaking Water Dangerous? Furnace Leaking Reasons & How to Fix It

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Having a heated home is essential at times of extreme winters and snowstorms. Canadians know the value of having a heated furnace fully working when necessary; however, having a faulty appliance can be quite frustrating. One issue they may present with furnaces is water leaking – when that occurs, many homeowners wonder how dangerous it is and how they can fix this problem.

Is Furnace Leaking Water Dangerous?

Yes, Water leaking from a furnace is extremely dangerous due to the risk of electrocution it imposes. When witnessing this incident, homeowners must immediately turn their furnace off, clean the water and contact a professional contractor to deal with any necessary repairs.

Why is my furnace leaking water? Top 4 Reasons for Furnace Leaking Water

A furnace leaking water can happen during any weather condition and for a number of reasons. Whether the furnace is leaking water in the summer or winter, it can be due to condensation, a faulty humidifier or an overflowed pipe.

There are a number of causes that can make a furnace show signs of damage and have water leaking as a result. Here are some of the reasons for water leaking from furnaces that homeowners should pay attention to:

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1. Condensation Leak

This is a very common reason for water leaking in furnaces. Highly efficient furnaces have a cool exhaust that produces a lot of condensation that leads to a floor drain, or to water dripping from the furnace.

Different parts of the furnace can produce condensation and cause leaks:

Drain hose

The drain hose of a furnace can easily clog due to excess dirt or dust in its draining tube, resulting in damage or disconnection and, eventually, causing water to come out of the furnace.

Drain line

In furnaces, water flows through a drain line that, if ever clogged, disconnected or damaged with cracks and holes, can cause water leaking.

Condensate trap

Condensate traps in furnaces are also subject to clogging. When condensate traps get clogged, water can overflow and leak from the furnace.

Condensate pump

Water drains to condensate pumps, and these parts can easily clog when the drain is blocked. A faulty pump can cause water to back up and leak from the furnace; in this situation, a professional will need to replace the furnace completely. Most pumps last between 3 to 5 years, and after this time period, they tend to clog often.

2. Faulty Heat Exchanger

Apart from condensation, heat exchangers in a furnace can also cause water leaks. When the heat exchanger captures heat for a home and the gases cool down, they eventually condense to liquid form. Furnaces that leak due to heat exchangers often require a full replacement.

3. Furnace Humidifier Leak

A humidifier can easily leak inside a furnace, and a professional HVAC specialist can look into it when checking for any furnace leaks. Humidifiers sustain a lot of liquid; therefore, leaking can be expected from them. A technician can alert homeowners of a leaking issue caused by humidifiers very early on and easily solve the problem.

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4. Drain System Clog

A system clog often happens when an air conditioning shares the drain system with a furnace, and a clogging issue sends water to the furnace, resulting in leaks.

How to Fix Leaking Water from Furnace?

furnace leaking condensate water

Water leaks in furnaces are a huge, dangerous issue and can cause serious accidents. The best way to fix water leaking from furnaces is by contacting a heating and cooling specialist like ALP Heating – they will be capable of quickly assessing and diagnosing what is causing the water leak on your furnace and fixing it right away in the safest way possible. 

However, you can fix leaking water from the furnace if you keep the furnace in good condition. It will also help you prevent other furnace problems.

FAQ About Furnace Leaking Water

What can I do if my furnace is leaking water?

If you notice water coming out of your furnace, it is best to contact a specialist to fix the issue. Water leaking from furnaces is extremely dangerous, and a professional in cooling and heating knows how to deal with the problem appropriately.

What is causing my furnace to drip water?

Water can overflow from your furnace if there is a lot of condensation, or an issue with the furnace’s humidifier, heater or drain system.

Is Furnace Leaking Water Dangerous?

Yes, a furnace leaking water can be dangerous. Water near electrical components increases the risk of electrocution and short circuits, potentially causing fires. The moisture can also lead to mold growth, which compromises indoor air quality and poses health risks. If you notice water leaking from your furnace, turn off the system immediately, clean the area, and contact an HVAC professional for safe repairs.

Why Is My Furnace Leaking Water from the Bottom?

A furnace leaking water from the bottom usually results from one of the following issues:

  1. Condensation Leak: High-efficiency furnaces produce condensation, which flows through a drain line. If the line clogs or cracks, water can pool at the furnace’s base.
  2. Clogged Drain Line: Dust, debris, or mineral buildup can block the drain line, causing water to back up and leak from the bottom.
  3. Faulty Humidifier: If your furnace has an integrated humidifier, a leak in its water line can lead to water pooling around the base.
  4. Broken Heat Exchanger: A cracked heat exchanger can cause condensation to escape, resulting in water accumulation at the bottom.

To prevent further damage, turn off the furnace and seek professional assistance to diagnose and fix the issue promptly.

Can ALP Heating assist me with my water-leaking furnace?

Our contractors at ALP Heating are experts in all cooling and heating systems, and they will know right away what is causing water to leak from your furnace. If you want this issue resolved right away, call us or visit our website – and we will fix your leaking furnace right away!

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