Noticing a puddle of water near your furnace can be alarming. After all, furnaces aren’t supposed to leak water. While it might seem odd, this issue is more common than you think and can result from several factors. Understanding why your furnace is leaking can ensure you address the issue quickly and avoid potential damage to your heating system or home.

Before jumping into maintenance tips, you should know the warning signs that your water heater may be struggling:
Water temperature issues (lukewarm water, hot water running out too fast, or no hot water at all).
Rust-colored water coming from your taps.
Strange noises like popping or banging from the water heater tank.
Leaking or pooling water at the base of the unit.
If you notice any of these problems, immediate action is needed. While some fixes can be handled on your own, severe issues may require professional service.

High-efficiency furnaces (classified as having an Annual Fuel Utilization Efficiency, or AFUE, rating of 90% or higher) use a process that creates condensation. This water should typically drain through a condensate line. If the condensate line is clogged, cracked, or improperly installed, water can leak and pool near the furnace.
Solution:
Check the condensate line for blockages or damage.
Clean the line with a long brush or flush it with a mixture of water and vinegar to remove any buildup.
If the line is damaged, it will need to be repaired or replaced by a professional

If your home has a whole-home humidifier attached to your HVAC system, it might be the source of the leak. These humidifiers are often installed on the furnace, and a faulty or clogged water line could cause water to leak and appear near the furnace.
Solution:
Inspect the humidifier’s water supply line and drain line for any signs of cracks or blockages.
Tighten loose connections or replace damaged components as needed.
If in doubt, contact an HVAC technician to assess the humidifier.

Both high-efficiency furnaces and standard HVAC systems often have a drain line to remove excess moisture. Over time, these lines can become clogged with debris, preventing proper draining and causing water to back up and leak from the furnace.
Solution:
Locate the drain line and check for any visible clogs.
Use a wet/dry vacuum to remove any blockages or flush the line with clean water.
If the issue persists, consider consulting a professional for a thorough cleaning or inspection.

The anode rod is designed to prevent rust in your water heater tank by attracting corrosive elements. Over time, it wears out and needs replacement.
How to do it: Remove the anode rod from the top of the tank to check its condition. If it’s heavily corroded (less than half an inch thick or coated in calcium), it’s time for a new one.

Schedule Regular Maintenance:
Have your furnace inspected by an HVAC professional at least once a year to catch potential issues early and ensure all components are functioning properly.
Keep Drain Lines Clear:
Check your condensate lines and pumps periodically for clogs or debris buildup, especially if you’re using your furnace heavily during cold months.
Change the Air Filter:
A dirty air filter can cause your furnace to overwork, which may lead to condensation-related issues. Replace filters every 1-3 months, depending on your system and usage.

A leaking furnace is undoubtedly inconvenient, but it’s often a solvable problem once you identify the cause. Whether it’s a clogged drain line, a broken pump, or an issue with your humidifier, addressing the root of the problem with the right solution can help prevent further damage and keep your home comfortable.