Why Does Your Air Conditioner Leak Water? Expert Help in Katy, TX

When an air conditioner leaks water indoors, it can be a tricky situation requiring expert help. And fast! Find out why air conditioners sometimes leak water and how to prevent the problem. This way you can react quickly, if it happens to you.

If you see water leaks, we suggest getting to the bottom of the issue sooner rather than later. Water damage causes more extensive damage the longer it’s left unattended. In humid climates like those where we operate in Katy, Texas, mold and mildew growth is a big concern. It can affect air quality indoors.

What Are the Top Reasons an Air Conditioner Might Be Leaking Water?

The biggest reasons an air conditioning unit may be leaking water are:

1. 1. A clogged condensate drain.
   2. Rusted or damaged drain pan.
   3. A frozen coil that is defrosting.
   4. Failed contactor which keeps the unit running nonstop.

Let’s dive a little deeper into each possible cause of AC water leaks.

1. Water Leaks Caused by Clogged Condensate Drains

We find clogged condensate drains most often in the spring, middle of summer, and then again in the late summer/early fall in Katy, Texas. The condensate drain removes water that accumulates on your evaporator coil and funnels it outdoors. The drain can accumulate build-up when the air conditioner starts to run a little less often.  Because the weather in Katy, Texas is hot and humid, a a slimy mixture of dust, mold, and algae can build up and clog a condensate drain line. Yuck!

When a condensate drain is working properly, it drips outside when the air conditioner is humming along, removing humidity from the air. When the outside condenser turns off, it will stop dripping outside. If the condensate drain is clogged, the drain will also stop dripping outside while the drain pan is filling up indoors. If the drain pan overflows, it can be a messy situation. 

What Should I Do Next?

First turn off your HVAC unit to stop water production. If you have a float switch installed on your drain pan, your air conditioner may stop on its own. If that does not stop the water from leaking indoors, then the issue may be related to plumbing, not the air conditioner.

A general rule of thumb is if the water is hot, the leak is most likely tied to the water heater. If the water is cold, it could be coming from the air conditioner or be a supply plumbing issue. 

Not sure where the leak is coming from? Call a licensed air conditioning and heating professional who can diagnose and fix the issue quickly. If it is a clogged condensate drain, your HVAC technician can blow out the clog. They can show you where the pipe is and explain how to maintain it yourself. Chemically-treating a drainline is typically included in most HVAC preventative maintenance plans. 

ProTip: Do NOT use Liquid Plumber or other acidic mixes to clear a condensate drain line. Vinegar is the low-cost solution we recommend homeowners use if they want to maintain the line themselves.

Good to Know

If your clog doesn’t easily clear, it may require manual treatment to clear the line. True story. One homeowner did not tell us they had used sulfuric acid on their condensate line. Unfortunately, this treatment did not clear the clog. They called us for help, but did not tell us what they had tried. When we manually broke through the clog, liquid spilled everywhere and began burning our hands. Please do your technician a favor and tell them what you tried to avoid this hazardous situation.

2. Water Leaks Caused by Rusted Out or Cracked Condensate Drain Pans

In Katy, Texas and Far West Houston, excessive humidity can cause drain pans to rust out or crack over time. The drain pan collects water that drips off the evaporator coil during the cooling process. If the pan is cracked or damaged, it can leak water onto the floor, down the walls, and through the ceiling. Many drain pans are made of galvanized metal, but we have seen more plastic drain pans, which can crack after exposure to extreme heat. 

If poor-quality PVC pipe is used for the drain, it can become detached and cause water issues. Most people don’t realize they have two drain pans. One is located inside the indoor evaporator coil and the emergency drain pan is located under the evaporator coil.

Especially if your condensate drain has been maintained using bleach rather than vinegar, these drain pans can cause a big mess when they start to rust out. Exposure to bleach accelerates the rusting process. As the rust develops, it looks like red dirt from East Texas accumulating on the pan. It can happen faster than you think.

Because this is something we do see on a regular basis, we install lifetime drain pans that are guaranteed to last a lifetime of the system and hold up to the elements on all of our new air conditioner installations.

What Should I Do Next?

First things first, turn off your air conditioner to stop the accumulation of water. Then, call your AC technician who will inspect the condensate drain to determine if the source of the water. Sometimes it is a clog in the condensate drain line AND a rusted or damaged drain pan.

Your favorite AC technician can install a new drain pan, eliminating concerns about water leaks. Ask your favorite AC technician if they have a solution if a rusted drain pan happens to you more than once. 

3. A Frozen Coil Causes Water to Pool Due to Low Refrigerant or Poor Air Circulation

A frozen coil can cause water leakage, but it is often not a huge flood of water all at once. Several reasons can cause this annoying problem. Homeowners can check some themselves.

What Should I Do Next?

First, check your air filter and replace it if it’s dirty. Believe it or not, excessively dirty air filters can cause your air conditioner to break down. It’s easy to prevent this problem by regularly changing your air filters. Some mini-split systems have washable filters, so check those, too.

Next, ensure there are no obstructions around your air conditioner unit that could block airflow. Sometimes, furniture and curtains can block air vents and make it difficult for the air conditioner to operate. If you are not sure where your air intake and outtake registers are, your HVAC technician will gladly show you. Just ask.

If your air conditioner or heat pump is low on refrigerant, you’ll need the expertise of a licensed professional to check that for you. Small pinhole leaks or even big ones can happen when the system is starting to show its age or it has been running nonstop during a heatwave. It’s best to turn the system off and let it unfreeze, so your AC technician can properly diagnose the system.

Good to Know

If you have a brand-new home and air conditioner and find leaks frequently, its possible that your air conditioner was not properly sized or some other installation mishap is causing the problem. We have spotted air registers that were accidentally covered by sheetrock, drains that were not properly connected, and air conditioners that simply needed someone to check them over thoroughly to ensure that small hiccups don’t cause bigger problems down the road.

4. Leaks Caused by a Failed Contactor

A failed contactor located in your outside condenser can cause an issue with water leaks but this is more rare. A contactor that is not working properly can cause your air conditioner to run nonstop. This can cause your system to freeze up. Ice can build up over the internal condensate drain and out to the secondary drain pan. When it thaws out, it looks like water pooling.

Contactors are electrical parts that fail from time to time and are easy to replace. The water damage resulting from this failure is a bit more rare, but it can happen.

What should I do next?

If you try to turn the system off at the thermostat, but the outdoor unit continues to run, you may have to turn the power off at the breaker. Then,  call a professional technician to inspect the condenser for a diagnosis.

How Can I Avoid Water Leaks from My Air Conditioner in the Future?

We recommend servicing your air conditioner twice a year, once in the spring and once in the fall. These are great times to check and treat your condensate drain (in the spring and fall), check refrigerant levels (in the spring), and make sure your heater is operating safely (in the fall).

1. Maintaining Your Condensate Drain Line

This type of maintenance is part of our regular preventative maintenance (AC checks, AC tune-ups) we do on air conditioners in the spring and early fall.  If you have frequent drain issues, your AC technician can recommend algicide tabs or an enzymatic solution that is long-acting.

DIY Condensate Drain Maintenance  – You can service your drain yourself. Because of Houston’s humidity, we recommend at least four times a year to pour a one-half cup of plain, white vinegar down your condensate drain. The drain line and pan is usually located under your evaporator coil in your attic or indoors with the piping leading outdoors. 

We don’t recommend using bleach because it’s an oxidizer. Bleach reacts with copper, zinc, and aluminum and can cause pinhole leaks and rust. 

2. Installing a ceiling saver/float switch

You can also protect your ceilings and walls from water leaks by having your HVAC contractor install a “ceiling saver” or “float switch.”  These handy devices turn off the air conditioning unit if the drain pan fills up. This only happens when the drain line is clogged. The float switch will keep your air conditioner from pumping out more water into the pan, eliminating costly spills and sheetrock replacement. We install float switches that come with a visual and auditory alarm on all of our new HVAC installations. This alerts the homeowner that there is a water issue immediately. 

Pro Tip: If you are getting a quote on a new system installation, make sure your HVAC contractor includes this safety feature.

3. Installing a UV light

Another tactic we recommend is installing an Ultraviolet (UV) Light in the evaporator coil. This improves air quality in the home and reduces the grime and slime that can develop on the evaporator coil and the condensate drain line. Because our climate is so humid, the air conditioning equipment parts that take out humidity from the air are constantly damp and that is a recipe for a build-up of dust, mold, and algae. 

Pro Tip: Ask how often the UV light requires replacement so you know that in advance. The one in my house requires replacement every two years or so. For most manufacturers, it’s either one or two years.

4. Replace Air Filters Regularly

Replace your disposable air filters at least once each season. You can also ask your favorite AC technician if they offer media filters, which are thicker and can last longer. We have a whole post with tips on where to find air filters in Fort Bend County, how to install them, and how to maintain filters if you have a mini split where the filters are washable. 

Pro Tip: If you’re not sure, ask your AC technician to recommend a replacement schedule that delivers the optimum efficiency and filtration for your specific system. Air filters keep your system clean and keep your air conditioner working properly. 

Looking for Expert Help in Katy, Texas? We Can Help

If you are in need of expert advice on maintaining and repairing your air conditioning system, contact the cooling experts at Terry’s A/C and Heating at 281-495-7830. We specialize in installing, maintaining, and servicing all makes and models of air conditioning equipment for residential and commercial customers in Katy, Texas and Far West Houston. We’ve seen all sorts of condensate drain issues and frozen coils causing leaks in homes and know how to fix the problem quickly.

Find out how we are different from other HVAC contractors in West Houston and contact my wife Summer today at 281-495-7830 to set up an appointment!