13 Causes of Your Air Conditioning Leaking Water

At ARS/Rescue Rooter, we often get panicked calls from homeowners wondering, “Why is my air conditioner leaking water?!” Sometimes, it’s simple condensation — to the relief of both the homeowners and ourselves.

Other times…well, it’s a problem that requires emergency attention, like a substantial amount of water pooling below the home’s AC unit.

The last thing you want is for your air conditioning to conk out, particularly during the blazing heat of summer. Read on for insight into what causes an air conditioner to leak water and how you can prevent AC problems.

Why Does Water Form in Your Air Conditioning System?

Water forming on or dripping from your AC isn’t bad in small amounts. It’s actually a natural byproduct of the AC doing its job.

Have you ever wondered how an AC makes cold air? Well, to tell you the truth, it doesn’t make cold air—it takes the heat out of the air that gets blown into your home.

A modern AC unit has both an outdoor and indoor unit that helps with proper airflow. The inside AC system has an evaporator coil that chills the warm air from outside to a comfortable temperature inside.

The remaining heat is absorbed into the coil and becomes hot gas. This gas passes through a compressor and then into a condenser, which releases it outside.

Because of this temperature change, condensation builds up as your AC unit turns hot air into cold air for your home. It’s just like when you have an iced drink on a hot day, and the glass sweats condensation.

A little condensation is okay because as it forms, dripping water lands in the drip pan, and excess water funnels through the condensate drain line. The drain pipes lead out of your home, so you won’t find your air conditioner leaking water as long as the pipes are functioning properly.

However, there are many ways in which this process can go wrong. If even one part is not working, you may notice a leak. That’s when a little condensation becomes a larger water problem.

Why Your AC is Leaking Water: 13 Potential Reasons

Is water leaking from an air conditioner dangerous? While you can still use a leaky air conditioner, it’s not recommended for extended use. You should turn off the system to explore different parts of your AC to find the problem, which will most likely be one of the 13 common reasons below.

AC leaks can be caused by simple problems like dirty air filters or more serious threats like frozen evaporator coils. Inspect your unit for the following causes of leaks.

1. Clogged Drain Line

A clogged drain line prevents an air conditioning unit from emptying any drain pans properly. They can become clogged with built-up dirt and debris, making it difficult for water to escape outside the home.

You can try to clear the blockage yourself with a wet/dry vac, but be careful not to damage the HVAC unit.

When in doubt, call a professional at 866-399-2885 to handle the clogged drain lines.

2. Damaged Drain Pan

As mentioned above, a drain pan is crucial for allowing excess condensation to drain out of your unit. If the drain pan is damaged and the water flow obstructed, that may cause a water leak. Since the drain line leads outside the home, you may find leaking water inside if the drain pan cannot filter the condensate properly. This can lead to water damage over time if left untreated.

If you have an older unit, it may have a rusted drain pan that prevents the dripping water from reaching the condensate line.

You can replace the drain pan, but if that doesn’t fix the problem, call an HVAC technician.

3. Disconnected Drain Line

You’ll find your air conditioner leaking water inside your home if there’s a disconnected drain line! The drain pan funnels water into the drain line, but a severed connection sends water leaking all over instead of leading it outside the home.

An AC system leaking water due to a problematic water drain line requires professional attention to repair. When in doubt, have your AC leak looked at by an HVAC technician for the best results.

4. Broken Condenser

If your condenser is broken, then the heat that’s usually released ends up stuck and causes leakage. Damage can include dents, holes, or cracks, which will cause the refrigerant to leak.

The most obvious sign of a broken condenser, other than the water leaking, is decreased airflow, in which case it will take longer for your home to cool down.

It’s best to schedule an appointment with a professional to discern the extent of damage to the condenser. It could be a minor problem that’s fixable in an afternoon, or it could require a complete replacement.

5. Broken Condensate Pump

An air conditioner leaking water may be due to a condensate pump failure. This doesn’t mean the condensate pump is faulty, necessarily, but it can mean a drainage issue is causing water accumulation to spill over.

If the pump cannot drain water, manually empty the drain pan to see what the issue is. If the pump doesn’t work, it’s time to replace it.

6. Full or Damaged Condensate Pan

Most AC units have two pans to assist with collecting and releasing excess water. We’ve already discussed the drain pan, so now it’s time for the condensate pan. Excess water can build up due to a frozen evaporator coil or a clogged condensate line, causing water to back up into the condensate line.

The pan can fill with natural debris like mold, dust, or maybe even bugs or small animals, depending on the size of the unit.

It’s best to let a professional check your condensate pan rather than trying to do it yourself. Schedule an appointment today!

7. Frozen Evaporator Coil

Over time, the evaporator coil can clog up. Instead of cooling hot air and improving indoor air quality, it gets dirty and slows down as refrigerant can’t pass through the coil into the unit. With no heat to absorb, the coil gets colder and colder until it freezes and your air conditioning unit stops.

To fix a frozen coil and restore airflow to your home, you’ll need to start by turning off your AC. You’ll notice your AC dripping water, but this is just the unit thawing out. Call a professional at 866-399-2885 to look at the unit later to ensure everything runs smoothly.

8. Dirty Air Filter

Your AC unit has an air filter. When you turn your AC on, it captures particulates so they don’t get into your home. Over time, your filter will get dirty and potentially blocked.

A dirty filter causes the air conditioner to work harder than normal. This extra strain makes it difficult for oxygen to reach the evaporator coil, which can cause the coil to freeze when the necessary heat is not absorbed.

You’ll want to make sure the air vents are clear and not blocked by any debris. For the best results, replace your air filters once a month. A clean air filter will improve air quality in your home and prevent harm to the unit from freezing or water damage.

9. Outdoor Temperatures Too Cold to Run AC

Do not operate the AC unit if the outside temperature is too cold. This can cause the coils to freeze and damage the unit. Instead, wait for the weather to warm up before turning on the unit.

A professional will advise you not to run the AC when the temperature is under 65 degrees Fahrenheit.

10. Low Refrigerant Level/Leaking Refrigerant

If your AC doesn’t have enough refrigerant, you’ll find the air conditioner leaking water. A hissing or bubbling sound can indicate you’re low, or, if your home feels warmer than usual, you may need to check the unit.

If you catch a refrigerant leak in time, you can repair the damage before it gets too bad. You can replace the refrigerant yourself or contact a professional to check the system and perform routine maintenance.

11. Improper AC Installation

Our technicians know the best and most cost-efficient approaches to fixing air conditioners leaking water, but sometimes the issue is because of poor installation by another company’s technicians. Water leakage from faulty installation can’t be fixed by DIY methods like a long wire brush or a float switch—it requires a professional.

If the problem is left too long, built-up water located underneath your unit can destroy whatever the unit is resting on if improperly drained.

Also, if the HVAC unit is too big or too small for your home, it won’t regulate circulation properly within the structure. You can contact a professional to replace the system so that your home is correctly cooled.

12. Thermostat Working Incorrectly

Your thermostat tells the evaporator coils in your AC how cold your house should be, so when the thermostat starts to malfunction, it affects the air conditioner. If the thermostat changes the temperature constantly, that can cause strain on the unit, leading to various problems. If the temperature drops too low, it can cause the coils to freeze over and then leak.

Make sure your thermostat is set to “auto” or “cool” to ensure your house is comfortable but not cold enough to affect the AC. If the thermostat continues to act up, you’ll need a professional to look at it and figure out the problem.

13. Damaged Insulation

Insulation inside your AC helps reduce the amount of condensation produced within the unit. If it’s damaged with holes or cracks, it won’t work properly, leading to leaks. It can even lead to parts of your AC freezing due to water within the unit cooling too much.

Broken insulation can decrease your AC’s performance, raise your energy bills, and, of course, cause leaks.

While you can replace or repair damaged insulation on your own, it’s a delicate process. If you have no experience, it’s best to let a professional handle the job to prevent further damage to your AC unit.

Trust ARS/Rescue Rooter for Your AC Repair Needs

What does it mean when your air conditioner leaks water? It means something isn’t working the way it should. Obvious water leakage from your AC unit is never a good sign. Water damage is expensive and can ruin your home.

Thankfully, you can prevent that kind of damage by contacting the air conditioning repair professionals at ARS/Rescue Rooter! We’ll be happy to take a look at your unit, diagnose the cause of the leak, and get your system in like-new condition again.

Schedule an appointment today at 866-399-2885! We even provide emergency services if it’s too uncomfortable to wait.

If you’re still looking for more information, read our FAQ section below.

Answers to Customers’ Frequently Asked Questions

How do I stop my air conditioner from leaking water?

To stop your air conditioner from leaking water, you should first turn off the unit to prevent more leaks from occurring. Next, you should open your unit if you can, and if you can’t, call a professional to find out what’s going on.

You may find that it’s either a simple problem or that it’s time to call a professional.

Can I still use my AC if it’s leaking water?

If your AC is leaking a large amount of water, then no, you should not still use it, because the water will cause a variety of larger problems within your unit with continued use. If it’s just the usual condensation, it’s fine to continue using it.

If you’re not sure, call a professional.

What do I need to do to address a broken thermostat that makes my air conditioner drip condensed moisture?

Begin by verifying the settings you programmed into the thermostat and installing fully charged batteries. The location of the thermostat can influence its operation, so keep it away from heat sources and shield it from sunlight that could distort its reading of your home’s temperature.

If you discover the thermostat is still malfunctioning, contact an expert to fix or replace it.

To keep water from dripping out of my air conditioner, what do I need to do to clear blocked condensate lines?

Customers often call us to fix water leaks coming from their air conditioner’s clogged condensate lines. If lines are clogged by algae, debris, or dirt, water cannot readily flow. As water accumulates, it starts leaking from the AC unit.

Do-it-yourself homeowners can attempt to break up a clog by using a pipe cleaner, a long wire brush, or a wet/dry vacuum cleaner—but if you lack the experience or knowledge, ARS/Rescue Rooter is standing by to assist!

Why is my central AC system leaking water?

If you’re wondering, “Are air conditioners supposed to leak water?” you should know that the sudden appearance of a pool of dripping condensate can indicate a serious problem. Leaks in AC systems can occur because:

• The air filter needs cleaning or replacement.

• The evaporator coil is frozen.

• The refrigerant level is low.

• Condensate lines are clogged.

When water doesn’t properly drain, it will drip or overflow, potentially causing property damage. The professionals at ARS/Rescue Rooter are adept at determining why a central AC unit is leaking and will come up with a customized repair plan to take care of the situation for you.

What can I do to keep condensed moisture from dripping out of my air conditioner’s vent?

When you notice drops of condensation falling out of the vent, it may indicate the evaporator coil is frozen or dirty. An AC system’s evaporator coil pulls moisture out of the air as it chills the warm air coming from outside. Frozen and dirty coils cannot keep up with the heat and humidity, leading to condensed moisture dripping out of the vent.

For optimal performance, change air filters according to the manufacturer’s recommended timetable, and schedule annual maintenance from ARS/Rescue Rooter. Our leak repair experts will make sure that the refrigerant level is adequate.

Another tip for avoiding condensed moisture leaking is to not run your AC when it’s extremely cold outside.

How do I unclog my AC drain line?

To unclog your AC drain line, first turn off your AC unit to prevent any injuries or further damage to your unit. Once that’s done, you have a few choices for how to clean out your drain line:

• Clearing debris by hand: If the problem is due to large pieces of debris, you can carefully remove them by hand.

• Using a wet/dry vacuum: Make sure to use a vacuum that’s powerful enough to suck out any wet or dry debris stuck in your line.

• Pouring a DIY mixture: Sometimes, the debris can be small and sticky, so people turn to pouring mixtures with vinegar or bleach down their lines—we suggest talking to a professional first to prevent permanent damage to your AC.

• Blowing air: Depending on your unit, you may be able to use bursts of air to clean out your line.

• Chemical drain cleaners: As with DIY mixtures, we suggest you talk to a professional before using drain cleaners.

• Flushing water: If the debris is loose enough, you may be able to flush it out with water.

• Pipe cleaners/snakes: These are professional plumbing cleaning tools; we suggest you don’t use them without prior experience because you can easily damage your AC.

How long will AC last with a leak?

How long your AC will last with a leak will depend on the severity of the leak and how it’s caused. It can be a couple of weeks or months. To prevent as much damage as possible, call 866-399-2885 to get a professional to look at your AC—this could be the difference between needing a repair or a replacement.