How to Fix a Leaking AC Unit & Top 3 Causes


How to Fix a Leaking AC Unit & Top 3 Causes

If you have a central air conditioning system in your home, you have more than likely experienced a water leak from your unit at one point. Causes for these AC water leaks can vary but are always an inconvenience to deal with. So, continue reading and you just might figure out what’s causing your air conditioner to leak and how to better prepare yourself!

Do you have an AC water leak?

Tiger Services is proud to provide homeowners in the San Antonio area with the essential tips and tricks they need to properly maintain their HVAC systems.

Cause #1: Your AC Drain Line is Clogged

Every air conditioning unit contains an indoor evaporator coil (which produces condensation caused by pulling humidity in the air). To catch this condensation, a drip pan is located beneath the indoor coil where the moisture can then flow into a connected drain line that carries the collection of water outside of the house or into the sewer. If the drain line has a clog, the water will no longer be displaced away from the home and backs up into the drain pan and into the house, causing an AC water leak. At that point, you might see water on the floor, ceiling or carpet. If you turn the system off, the water will eventually stop leaking into the house. The algae, sludge and dirt that is causing the drain line to clog up, will need to be cleared out.


To clear the drain line from the blockage, the pipe needs to be vacuumed out or blown clear with high-pressure air or nitrogen. Once clear, the pipe, pan, coil and filter need to be inspected to see what contributed to the issue. Many times, the drain line needs to be treated with some PVC compatible drain cleaner.

Tiger Services offers two unique products that could serve as an automatic drain cleaner dispenser so you would never have to treat the drains again. Or, we could simply deep clean all the sludge, calcium, dirt, slime and other build-up from the pipe (you should see what this drain line cleaner pulls out of the drain – ask the technician to show you). This clear drain solution cleaning process takes about 30 minutes and requires the technician to seal the line temporarily and flush it with water for a full deep cleaning. It is very impressive.

As an added service, we have a list of recommended sub-contractors to help homeowners with any needed carpet or sheetrock repairs due to water damage.

Most drain line blockages can be avoided with proper routine maintenance and an effective drain line cleaning program. As a professional air conditioning and heating company in San Antonio, Texas, Tiger Services can share with you all available programs to assist you.

Cause #2: Your AC Drain Line is Disconnected or Cracked

If you experience an AC water leak, it is important that the drain line (the pipe carrying the condensation collection) is properly inspected. It is very possible that someone or critter disconnected the line, causing misdirection of the water. Obviously, if the line has an air pocket in it or has become disconnected, it needs to be reconnected and corrected.


To find the disconnected pipe, a technician needs to follow the line to the outside drainage point.  If your home is a two-story structure and the indoor units are upstairs, attic access is needed for this process. The pipe will need to be reconnected or repaired. Tracking down the exact location of the issue can be time-consuming because of the number of tight crawl spaces.

Cause #3: Your Indoor AC Evaporator Coil is Frozen

If a filter has NOT been properly maintained or a motor has failed, the lack of airflow through the air ducts and across the indoor coil will cause the coil to ice up

(which can cause an AC water leak). So, look for ice on the refrigerant lines next to the indoor coil or the outside condensing unit. If you see ice, the system needs to be turned off and the system needs to thaw out.  Once the accumulation of ice starts blocking the water from draining or if the ice starts melting over the sides of the drain pan, water will be displaced and leak onto the ceiling and floor. The most common of those two issues is the filter has not been properly maintained.


When’s the last time you’ve replaced those dirty air filters? If the filter looks dirty and does not allow air to pass through, change the filter. Go ahead and turn the system to OFF and turn the fan to the ON position. You will want to make sure to reset that switch to the AUTO setting once everything is corrected. The thawing can take anywhere from 4 to 8 hours. Once the ice seems to be thawed, reset the thermostat to the cooling mode and fan to the auto mode. If the unit starts leaking water again, a service technician will be required to see the next course of action.

Frozen evaporator coils are a good indicator of poor airflow, typically caused by old and filthy air filters. Tiger Services is rated the #1 air filter provider by Aprilaire for San Antonio and the surrounding areas. Contact us today to get started with a maintenance plan to be proactive about maintenance for your air conditioning system! (210) 774-6322


Tiger Services Air Conditioning & Heating


111 E. Rhapsody Dr.
San Antonio, TX 78216


(210) 344-0060

Service Hours

8:00 AM - 8:00 PM | 7 Days A Week

Showroom Hours

8:00 AM - 5:00 PM | Mon - Fri

Tiger Services Air Conditioning and Heating Services maintains HVAC Heaters, AC Repairs AC Service and Maintenance and installs New Air Conditioning systems in San Antonio and the surrounding areas.

Tiger Services Air Conditioning and Heating Services is experienced at repairing HVAC and heat systems and have been in the business of keeping San Antonio comfortable since 1990. Tiger Services Air Conditioning and Heating Services at (210) 361-1926 today if you need an air conditioner or heating services. We respect your privacy and will never share your information.

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