Few things are more frustrating than discovering a puddle of water forming around your air conditioner. Not only can this be alarming, but it can also signal bigger issues that, if left unaddressed, may lead to water damage, mold growth, or costly HVAC repairs. If you’ve been wondering why your AC is leaking water and what you can do about it, you’re not alone.
In this article, we’ll break down five of the most common causes of water leaks in air conditioners and how to fix them—either on your own or with the help of a professional. By the end, you’ll have a better understanding of what’s happening and how to stop the drip before it turns into a disaster.
1. Clogged Condensate Drain Line
Your air conditioner removes humidity from the air as it cools your home. That moisture collects on the evaporator coils and drips into a drain pan, eventually exiting your home through the condensate drain line. Over time, that line can become clogged with dirt, mold, algae, or debris—causing water to back up and leak from the unit.
This is one of the most common reasons for water leakage. You may notice water pooling around your indoor unit, musty smells, or even the system shutting down due to a safety switch being triggered.
Fix: You can try flushing the drain line with a mixture of vinegar and water to break up any buildup. However, if the clog is deep or persistent, it’s best to call a professional HVAC technician who can clear the line using a vacuum or pressurized tool and inspect for underlying issues. Regular AC maintenance can help prevent this issue from returning.
2. Dirty Air Filter
When your air filter is clogged with dust and debris, it restricts airflow to the evaporator coils. This causes the coils to get too cold and eventually freeze over. When the ice melts, all that water has to go somewhere—and often, it ends up leaking out of your system and onto the floor.
This issue can be especially common during the peak of summer when your AC is working overtime. Poor airflow, reduced cooling performance, and ice buildup on refrigerant lines are all warning signs to watch for.
Fix: Replace your air filter every 1 to 3 months, depending on how often you use your system and whether you have pets or allergies. Not only will this help prevent leaks, but it also improves indoor air quality and energy efficiency. Consider adding this to your regular home maintenance checklist.
3. Low Refrigerant Levels
Low refrigerant levels are another culprit behind a leaking air conditioner. When there’s not enough refrigerant in the system, the pressure drops, and the evaporator coils can freeze. Once that ice melts, it creates excess water that may overflow the drain pan or drip into unwanted areas.
You might also notice longer cooling cycles, higher energy bills, or strange noises like hissing or bubbling—signs that your AC may have a refrigerant leak.
Fix: Handling refrigerant requires special equipment and certification. If you suspect your system is low on refrigerant, call a licensed HVAC technician to diagnose the issue, recharge the system, and check for leaks. Never attempt to add refrigerant yourself, as it can be hazardous and cause further damage if done improperly.
4. Damaged or Rusted Drain Pan
The drain pan underneath your evaporator coil is designed to catch and funnel condensation safely out of your home. However, over time—especially in older AC units—it can rust, crack, or corrode, leading to water escaping the pan and pooling below the unit.
If your AC is over 10 years old, a damaged drain pan is a likely suspect for unexplained leaks.
Fix: Inspect the drain pan using a flashlight. If you see any cracks or rust holes, it’s time for a replacement. While some homeowners may attempt this as a DIY project, it’s typically best to leave it to a pro—especially if the pan is part of a larger internal system that needs to be disassembled.
5. Improper AC Installation
If your air conditioner was installed incorrectly, water may not drain properly. Units need to be slightly tilted toward the drain line to allow gravity to do its job. A poorly sloped system can result in water pooling inside the unit and eventually leaking out. Loose or disconnected drain lines can also contribute to improper drainage.
Improper sizing can also strain the system and lead to excess condensation. An oversized AC unit may short-cycle, leading to insufficient moisture removal and water buildup.
Fix: Unfortunately, this isn’t something a homeowner can fix on their own. A professional will need to inspect the system’s positioning and configuration to correct any installation errors. If the unit is the wrong size for your home, it may need to be replaced with one that matches your cooling needs.
When to Call an HVAC Professional
While some minor issues—like changing air filters or cleaning a drain line—can be handled on your own, other problems should always be addressed by a certified HVAC technician. Low refrigerant, electrical malfunctions, and improper installation are best left to the experts. Waiting too long to address a leaking air conditioner can result in significant water damage, mold growth, or even system failure.
If you’re dealing with an AC leak and aren’t sure what to do, give Trident Heating & Cooling a call. Our trained professionals can quickly diagnose the issue and recommend the best course of action—saving you time, money, and stress.
Preventing Future AC Leaks
The best way to avoid AC leaks in the future is through regular maintenance and a little proactive care. Here are a few quick tips:
- Schedule annual AC tune-ups to catch small problems before they become major issues
- Change your air filter regularly (every 1–3 months)
- Clean the area around your AC unit to reduce dust and debris
- Make sure your condensate drain line is clear and flowing properly
- Ask your HVAC technician to inspect the drain pan and refrigerant levels during your next service call
These simple steps can go a long way toward keeping your AC system running efficiently and leak-free all summer long.
Final Thoughts
Water leaking from your air conditioner isn’t just an annoyance—it’s a warning sign. Whether the issue is a clogged drain line, frozen coil, or something more serious, it’s important to get to the root of the problem before it leads to expensive damage.
Trident Heating & Cooling is here to help. Our experienced team offers fast, reliable service throughout the Rochester area, and we’re always just a call away when you need us. Don’t wait for a small leak to turn into a big problem—contact us today and get your comfort back on track.