AC Leaking Water? Here Are 5 Common Causes and Solutions

Noticed your AC leaking water? Even though condensation is a normal part of the cooling process, you’ll want to take a closer look if water is constantly coming out of your air conditioner. If there’s an issue, addressing it quickly could spare you from a slew of bigger (and more expensive) problems, including water damage and a broken AC unit. Here are five common causes for why your AC is leaking water.

1. Blocked Drain Line

The drain line transports excess water out of your AC unit to drain outside your home. Over time, it can collect dirt, mold, and deposits from the water, which can clog the line and prevent the water from draining—eventually leading to a leaky AC unit.

How to Fix It

There are a few DIY ways to clear a clogged drain line. For example, you can try flushing it with vinegar to get rid of any organic matter blocking the line, or you can suck out debris with a wet/dry vacuum. However, these methods work best on minor clogs, so if you have a more severe blockage, it’s better to call an HVAC repair pro.

2. Clogged Air Filter

As air moves through your AC unit’s air filter, the filter catches large particles and debris—including dirt, dust, and hair—to prevent these particles from entering your HVAC system and circulating through your home.

But if the filter is too dirty, your AC may struggle to pull air through the filter, which can cause condensation to build up and freeze inside the unit. When the ice melts, it can fill up the drain pan and leak out of your air conditioner.

How to Fix It

Replacing your air filter can solve this problem. If you aren’t already, make sure to change your filter every three months. But it’s better to swap out your filters every month or two if you own pets, have allergy sensitivities, or keep your windows and doors open often.

3. Low Refrigerant Levels

If your AC is low on refrigerant, your evaporator coil won’t be able to absorb enough heat from the air passing over it. If that happens, the moisture can condense inside the AC unit, resulting in a frozen evaporator coil that leaks as it melts.

How to Fix It

If your AC is still losing water after clearing the drain line and replacing the filter, you may have a refrigerant leak. Don’t try to fix this problem on your own. Refrigerant can be dangerous if inhaled or ingested, potentially leading to nausea, headaches, seizures, or loss of consciousness. Instead, hire an HVAC pro to check your refrigerant levels and add more if needed.

4. Drain Pan Issues

A drain pan collects water from the condensation in your AC unit before directing it into the drain line. As we’ve mentioned, a dirty air filter or lack of refrigerant can cause the drain pan to overflow, but those aren’t the only causes of a leaky drain pan.

After years of use, metal drain pans can corrode or rust, and polymer drain pans may crack. If so, water can seep out of the pan, leading to your AC leaking water. Improper installation can also cause a drain pan to overflow.

How to Fix It

Inspect the drain pan for rust, cracks, or other damage. You can use silicone sealant to repair cracks, but you’ll need to replace a rusted-out drain pan. If the pan was installed incorrectly, call a local AC repair pro to put it in the right place.

5. Faulty Condensate Pump

This pump pushes condensate water out of your air conditioner so that it drains safely outside. If it stops working, the water will stay in your system and start to leak out.

How to Fix It

You’ll need an HVAC pro to repair or replace a broken condensate pump. If you don’t know what you’re doing, trying to tackle this job yourself could lead to HVAC system damage, electrical shock, or fire. It can also void your warranty.

Will My AC Stop Leaking on Its Own?

Don’t expect your AC to stop leaking by itself. Air conditioner leaks have several different causes (including dirty air filters, clogged drain lines, or low refrigerant), all of which need to be addressed—either by you or an expert. You can solve some of these issues on your own, but be sure to hire an HVAC professional to deal with refrigerant or fix a broken condensate pump.