Why Is My Furnace Leaking Water?

Are you noticing dripping water around your furnace? Is a furnace leaking water dangerous? Why is your furnace leaking water on the floor? We have the answers!

It can be jarring to notice a water leak coming from your furnace. After all, furnaces are associated with heat output, which is generally unconducive to water leaks. But there are sound reasons for this phenomenon and even better, simple solutions to this unpleasant problem.

Furnace Leaking Water from the Bottom?

The most common reason for a furnace to leak water is a general lack of maintenance or clogging of some related system. 

The gasses and fuel from a furnace aren’t immune to reverting to liquid form. When there is a clogged component, these gasses can condense into a liquid and leak onto the floor.

How can you tell which component is causing the leak? Well, there are a few signs that could point to the culprit, depending on the type of furnace you have and what other systems are running concurrently with it.

Some of the most common parts to cause a furnace leak are:


  • Clogged condensation line
  • Overflowing drain pan
  • Secondary heat exchanger crack

To find out what is causing the leak in your furnace, you should call a professional HVAC service to come out and inspect the system.

Furnace Leaking Water When AC Is On?

If your furnace is connected to your HVAC system, the problem could be coming from an overwhelmed drain pan or condensation line. 

When you run your AC, it creates condensation that runs from the unit into the drain pan via a condensation line. If that line gets clogged, or if your furnace and AC are running at the same time and overflowing the drain pan, your furnace will appear to spring a leak.

Furnace Leaking Water in the Winter When Heat Is On?

If it’s freezing out and no AC is running, but you still notice your HVAC leaking water, the first question to ask yourself is: what kind of furnace do I have? Is it a high-efficiency furnace leaking water or a standard furnace?

If you have a high-efficiency furnace, the issue might still be with the condensation line or drain pan. These furnaces produce a lot of condensation that can drip all over your floor. Unfortunately, the leak could also be coming from a crack in the secondary heat exchanger, in which case, you will need to purchase a new furnace. 

If you have a conventional furnace, the problem might come from an improperly fitted vent pipe.

Some of these solutions will have easy fixes or necessitate a new furnace. Only an expert will be able to find out exactly why your furnace is leaking.

Contact Hearn Plumbing Heating and Air

If you’re asking yourself, “Why is my furnace leaking water?” there is only one way to find out for sure. Call the experts at Hearn Plumbing Heating and Air and schedule an appointment with us today!

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