Why Your Conventional (Non-Condensing) Furnace Is LeakingWater. Even though you have a non-condensing furnace, the root of the waterleakage will still be condensation. However, there could be 3 different sources of the condensation: Leakyhumidifier. Expert guide to furnaceleakingwater causes including condensation issues, clogged drains, and humidifier problems with repair solutions. If you noticed waterleaking from yourfurnace, you may be wondering what caused it.Small cracks in your humidifier can cause water to leak into the furnace. This can be prevented by doing regular humidifier inspections while you are checking our furnace. Learn whyyourfurnace is leakingwater, how to solve the problem correctly, and what you can do to prevent future furnaceleaks.A leakinghumidifier can occur when the water lines crack, break, or get clogged due to lack of maintenance. Whyis my heater leakingwater? A heater may leakwater due to blocked condensate lines, malfunctioning humidifiers, or issues with the condensate pump. These issues are common in high-efficiency systems, which naturally produce condensation. 6 Reasons WhyYourFurnace Might Be LeakingWater.Some furnaces come with built-in air handlers that have humidifiers, which make sure that the air flowing into the home from the furnace is not too dry. Therefore, humidifiers use water to add some moisture to the circulating air. Don’t panic!This excess water then leaks and drips onto the furnace, giving the impression that the furnace itself is the source of the leak. To determine if the humidifier is to blame for the waterleak, it’s important to inspect it thoroughly. If so, you may have an issue with yourfurnace’s condensate drain system and you’re likely experiencing a condensation leak.