Why is My AC Leaking Water?

Having a cooling system at your home can do wonders for keeping your family comfortable throughout the long summer months. However, you should be paying attention to your unit so that you can detect when it’s operating differently than usual. One common issue you may experience is water leaking from your indoor cooling system components.

A Note on How Air Conditioners Work

Before we jump into the most common culprits of your water leak, it’s imperative that you first understand how your cooling system actually operates. All home air conditioning systems have an outdoor condenser unit and one or more indoor air handler units. Inside the indoor unit will be an evaporator coil filled with pressurized refrigerant.

As the blower fan forces hot air from your home over the evaporator coils, the refrigerant will absorb the heat. This process will naturally cause condensation to occur on the surface of the evaporator coil. Think of this process as being very similar to a glass of ice water forming condensation on the outside of the glass.

These water droplets will fall off the evaporator coil and down into the drain pan. This pan has a drain that connects to a drain pipe, which typically runs to the outside of your home. When your system is working properly, excess humidity will be pulled out of the air and dispersed outside.

Clogged Condensate Drain

Probably the most likely cause of water pooling around your indoor air conditioning unit is a clog in your condensate drain line. Dust, dirt, algae, and other debris can enter your AC’s drain pan. Over time, this debris can build up and create a clog at the drain or somewhere in the drain line.

Unfortunately, this will stop water from being able to flow to a safe location outside your home. Instead, the water created by the condensation process will backup in your drain pan and eventually cause it to overflow onto the ground beneath. The drain and drain line will need to be cleared of debris to get your system back to working effectively.

Damaged Drain Pan

Another reason you may notice pooling around your indoor cooling unit is that your drain pan is damaged. Even a small crack can allow water droplets to constantly run out of the pan and onto your floor. Unless you physically damaged the drain pan by force on accident, it’s likely that it may just be old. Most cooling systems that are over 10 years old can experience rusting at their drain pans, which will lead to leaking. Regardless of the reasons that your drain pan is damaged, it will need to be replaced with a new one to prevent water seepage.

Evaporator Coils Thawing Out

One of the most frustrating issues you may experience with your air conditioning system is that its evaporator coils freeze up. This unfortunate situation can be caused by a number of different things, such as dirty coils, dirty air filters, low refrigerant levels, and even restricted airflow.

When you turn your system off or to fan mode, the built-up ice on your coils will thaw out fairly quickly. This can lead to an influx of water that backs up your drain pan and causes spillage. Whenever you’re letting your evaporator coil thaw out, you should regularly monitor your drain pan and remove excess water before it completely fills up the pan.

Faulty Condensate Pump

In cases where your indoor air handler unit is installed in the basement, you’re going to need to rely on a condensate pump to transport water from the drain pan to a safe location outdoors. If your condensate pump fails to run, water is going to backup indoors. In some cases, the pump or its float switch may be too clogged with debris to operate correctly and will need to be cleaned. In other cases, the pump itself may be faulty and need to undergo professional replacement service.

Leaking Drain Pipe

As with any sort of piping, it can deteriorate over time and fail. If you have an older cooling system with a metal drain pipe, it may have corroded and developed a leak. If you have a plastic drain pipe, it may have been inadvertently damaged and developed a crack. Either way, you’ll need to have the drain piping replaced to stop the water leak.

Disconnected Drain Line

Another issue that can cause water to leak out of your air conditioning unit is a disconnected drain line. This could be due to physical damage that caused the pipe connections to loosen. Or, it could be due to faulty drain line installation where the fittings weren’t adequately adhered together. Over time, faulty piping connections can loosen and end up falling apart. You’ll need to get the drain line fittings reconnected to your piping with the right adhesive to prevent further issues.

Imbalanced Installation

If you’ve recently had your cooling system installed and started to notice water pooling under your unit, it’s a likely indication of a bad installation job. Your air conditioning unit must be installed on level ground. This way, your drain pan can fill with water evenly. If your AC unit is installed on a slope, the water that enters the drain pan can be forced to one side and overflow over the pan’s edge. Unfortunately, to solve this issue, you’ll need to have your air conditioning system reinstalled on a level surface.

Faulty Pan Switch

In more modern-day air conditioning units, a drain pan switch is usually installed as an added safety mechanism. Its job is to sense when the water inside the drain pan hits a certain level. When it does, the drain pan switch will automatically turn the cooling system off. This is meant to help prevent the pan from overfilling and spilling over onto your floor. If your drain pan switch is faulty, it can allow your air conditioning system to keep running and end up overfilling your drain pan with water.

Running Your AC System With a Leak

Regardless of the reason that your air conditioning system is leaking water, it’s imperative that you shut it off when you first notice a problem. You don’t want to continue running it as this could lead to damage to your system’s internal components.

Additionally, the excess water will keep pooling around your indoor unit and can damage your flooring, walls, and anything else it comes into contact with. If left go too long, the excess moisture can even lead to unhealthy mold and mildew growth inside your home. You should opt for calling a professional to assess and repair the issue before turning your system back on.

Professional AC Service

Lightfoot Plumbing, Heating, Air & Electrical offers professional AC service for the entire Weatherford, TX and surrounding communities. We can also assist with all of your electrical, plumbing, heating, indoor air quality, and ductless mini-split needs. Give us a call today to schedule your next service appointment.