Why’s There Water Around Your Furnace During the Summer?

By: Brian Schutt  |  June 19, 2015

During normal operation, your air conditioner produces a significant amount of water in the form of condensation from your evaporator coil. That water gets channeled to the drain line—most often a 3/4 inch, white PVC pipe—and then flows to a floor drain, sump pump, or another type of drain.

When working properly, the only sign of water should be a periodic dripping noise. You should never see water on or around your indoor system, just hear it. If you do, then it’s a sign that something’s not functioning correctly.

If you’re proactive and have regular preventative maintenance done on your air conditioner, most risks of water damage are mitigated. But if it’s too late and you’re already seeing water around your furnace, here are the likely causes and the steps to take.


Causes of Water Around Your Furnace:

PVC Drain Line Plugged

As systems age, dust and dirt can collect on the evaporator coil, falling into and eventually plugging up the drain line. With this restriction, the water will push back into the coil and eventually spill onto the floor.

Filter Plugged

When the filter is plugged, it can reduce airflow through your coil. While this will most likely cause a frozen coil first, sometimes the airflow restriction caused by a blocked filter will cause water to develop.

Drain Pain Has Leak

If water has rested too long on the pan below the coil, rust and holes can develop and allow water to drain.

Problems With Condensate Pump

If your home has a condensate pump, then you have one more electrical component that can break down.


Steps to Fix Water Around Your Furnace:

1. Shut Off System

Look for shutoff switch, which looks like a light switch next to the furnace and coil, and switch it off. If you cannot find this, shut off the system at the breaker.

2. Clean Up Water Quickly

Sitting water will do quick damage to whatever it touches, so be sure to soak it up quickly.

3. Check Filter

Make sure no airflow through the filter has been impacted.

4. Place Vacuum Around PVC Drain Line

Using a water-safe vacuum (i.e. Shop-Vac®), remove any debris and potential clogs. Afterward, turn on air conditioning system and monitor to determine if this fixed leak.

5. Pour Water Into Top of Condensate Pump

If condensate pump does not react, it indicates a mechanical failure. If it does pump the water, then the drain line from pump to drain (or wherever water gets dispersed) is clear.

Call Homesense Heating and Cooling to Repair Water Leaking Around Furnace

If you’ve taken the above steps and still are seeing water in places it shouldn’t be, give us a call at 317.670.0171. Sometimes these issues require a quality contractor to disassemble air conditioner and furnace components to diagnose.


Brian Schutt


is the co-owner of Homesense Heating | Cooling. Born and raised in Indianapolis, he loves the city and its people, and is committed to bringing a servants mindset into the heating and cooling industry. One of the ways he does that is to translate the technical language of HVAC into the manageable and understandable for homeowners.

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