Goodman Furnace Leaking Water – What Could Be Wrong?

Goodman furnaces are some of the best units on the market. However, this doesn't mean that they can't run into typical furnace issues from time to time - a common one is leaking water. What causes a Goodman furnace to leak water? And better yet, how do you fix it? We have researched the main reasons why these furnaces may leak, and in this post, we will share them with you.

One of the main reasons a Goodman furnace may leak is condensation on the exhaust pipe located outside the furnace. The second most common reasons are issues with the humidifier or a clogged condensation drain. You may also find that the furnace may leak when the air conditioner unit is on, typically a result of a clogged or faulty drain. All of these issues are repairable.

If your Goodman furnace is working correctly, the only water you should see should be a periodic dripping on the outside condenser line. But if you see water gathering around the bottom of the furnace, this is typically a huge red flag that some components are not functioning properly. Continue reading to learn more about why your Goodman furnace may be leaking water and how to troubleshoot it.

A service man working on furnace, Goodman Furnace Leaking Water - What Could Be Wrong?

Reasons Why Your Goodman Furnace Is Leaking Water

Condensation clogs and leaks

You will find this most commonly in high-efficiency Goodman furnaces. These furnaces naturally produce condensation that is quickly swept away by the condensate line or the train tap. Unfortunately, these lines can get clogged at some point in time, and if they aren't clean, you may find yourself with a pool of water around the furnace.

You can quickly check the drain trap to see if there is a clog. If there is, you can use a shop-vac to clean it out. If the clog is related to a leak, you may want to call an HVAC technician to determine the source of the leak to prevent future issues.

Pump malfunctions

The condensation pump on a furnace is responsible for moving water through the lines. However, over time this pump can begin to malfunction, and the result is a leaky furnace. If you have checked the drain tap only to find that it is clogged free, the condensate pump may be the culprit. If this is the case, it's best to contact a technician to come and troubleshoot the pump and possibly replace it if needed.

Condensation from the exhaust pipe (aka "Flue pipe")

Another likely cause of leaking water in your Goodman furnace is from the metal exhaust pipe. This exhaust pipe carries condensation outside of the furnace in the form of gas. However, if the metal pipe has a leak or is not the right shape or size, all of the condensation will not be able to escape. And turn, when the gas cools down, it will run back into the pipe and leak out the bottom of the furnace.

Over time, this can cause a pool of water to develop around the furnace base, which can cause other parts to rust and corrode. You can usually see the pipe extending out the top of the furnace or from the side. If you see water leaking from it, the chances are that this is the culprit. This is another scenario where you'll want to call a technician to come and help you shoot the issue.

Humidifier issues

Many homes will have a humidifier installed inside the furnace to help keep the home moist during the dry winter season. If the humidifier starts to leak, it may initially appear that the furnace itself is leaking. However, closely inspecting the area around the furnace and the bottom of the humidifier can give you a better idea of where the leak is coming from.

Take a close look at the drain line, feed tube, and water tap line. If you notice that more water is pulled around these components, this is the leak source. If you believe that the humidifier is old and needs to be replaced, you should have a technician replace it.

Air conditioner issues

Air conditioner systems can also cause issues with the furnace. For example, if you noticed that the leak only occurs during the warmer times of the year or in-between seasons such as fall and spring, the air conditioner could be the issue. Air conditioners absorb water from inside the home and release the water as condensation through condensate lines and drains. However, if these lines become clogged or faulty in any way, this can cause water to gather around the furnace base. This would be another issue that would be best left in the hands of a trusted professional to fix.

Need a visual? Check out this video of a repairman fixing a leaking Goodman furnace:


Is furnace leaking water dangerous?

Yes, a leaky furnace can lead to hazardous conditions in your basement or attic, and it should be addressed immediately. If you are worried that the furnace may cause issues with electrical wires near its location, you should shut down the entire system and call an HVAC professional as soon as possible to mitigate the issue. Keep in mind that this isn't a problem that you will want to ignore or put off for a week or two.

Not only can the leaky water be a potential fire hazard, but it can also cause other components inside the furnace to become faulty, leading to a more costly repair job. Lastly, a leaky furnace can also cause water damage to your home if it's located in the attic. And this can be an especially expensive repair to fix, particularly if the water has leaked down the walls.

Why is my Goodman furnace leaking water?

Independent heating in a modern house

There can be a few reasons why your Goodman furnace may be leaking. The most common reasons may be a leaky humidifier, a clogged drainpipe, leaky or incorrectly-sized flue pipe. Sometimes the air conditioner system connected to the furnace can also cause leaks. Overall, you will find that the main reason why a Goodman furnace will leak is due to excessive condensation in some areas of the furnace.

You can try to troubleshoot the source of the leak yourself, as it may be a quick repair in some cases. If you can't find the source of the leak, however, it's best to contact a professional technician.

What happens when your furnace leaks water?

When your furnace leaks water, the water will pool around the furnace base, with the specific area depending on the source of the leak. If the water continues to leak and pull around the furnace, it will eventually cause rust within certain components and even eventual shutdown. The leaky furnace can also cause water damage and potentially hazardous conditions due to electrical wiring.

What to do if the furnace is leaking water?

Here are the steps to take when your furnace is leaking water:

If you notice your furnace is leaking, the first thing to do is shut off the system.

  1. Next, you'll want to get a mop, tiles, or cleaning cloths to clean up any water that has pulled around the base of the furnace or inside of the bottom panel of the furnace. When cleaning the inside of the furnace, be sure to use a lint-free cloth, as you don't want to induce a fire once the furnace is back up and working. You can also use a Shop-Vac to remove the water as well.
  2. Then, check the furnace filter to ensure that the leaks haven't impacted the furnace's airflow.
  3. Next, take a look at the drain tap for the furnace to see if there is a clog. If there is, use a Shop-Vac to clean it out.
  4. Next, take a cup full of water and pour it on top of the condensate pump. If the pump doesn't react or start pumping out the water to the drain line, it's an indication that there is a mechanical failure with the pump itself.
  5. After troubleshooting the furnace, turn the unit back on to see if you notice any leaks. It's also a good idea to contact a service technician at this time.

Check out this shop-vac on Amazon.

How much does it cost to fix a leaking furnace?

The cost to fix a leaking furnace will depend on the cause of the leak. For example, if the heat exchanger is the source of the issue, it can cost anywhere from $150 to over $1,600 for a replacement exchanger. However, if the problem is simple flue pipe replacement, this will be less expensive and may range anywhere from $80 to $120, depending on your location.

If the humidifier and your furnace need to be replaced, this can range from $250 to over $600. This pricing depends on the type of humidifier that you have and any updates that need to be made to its corresponding parts. If you can replace the drain pump yourself, you can expect to spend anywhere from $40 to $60 for the pump itself. Replacing it is a reasonably straightforward process and can be done within about 20 to 30 minutes.

How do you clean a furnace drain trap?

Cleaning out the furnace drain trap is fairly easy. Here are the steps to do it:

  1. Start by turning off the power to your entire HVAC system.
  2. Next, locate the condensate pan, which is usually right under the air handler, and remove it.
  3. If the pan contains water, use a rag or a Shop-Vac to remove the water. Then clean the pan with soap and water.
  4. Next, find the condensate drain outlet and clean it with a wet and dry vacuum to suck any debris out of it. You can also use a plumber's snake.
  5. Next, find the access point for the drain line.
  6. Then, flush the drain with hot water or diluted white vinegar. You can also use diluted hydrogen peroxide as well. Let the solution sit for about 20 to 30 minutes, and then flush the drain again with lukewarm water.
  7. Next, let the water drain out and then and turn the unit back on. Be sure to let it run for a few minutes and confirm that it's working correctly.

Wrapping Things Up

As you can see, there are quite a few issues that may cause your Goodman furnace to leak water. Some of these issues can be fixed rather easily, while others may require the help of a professional HVAC technician. In both cases, it's best to address the leak immediately to avoid hazardous conditions in your home and potentially higher repair costs.

Before you go, be sure to check out some of our other posts:

8,000 BTU Air Conditioner – What Room Size?

Should A Window Air Conditioner Be Tilted?

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