AC Unit Dripping Water? Here’s What You Should Do

Is that puddle under your air conditioner just normal condensation, or could it be a sign of a costly problem waiting to happen? Many business owners and homeowners panic at the first sight of water near their AC units, but not all moisture signals disaster.

When your air conditioner starts dripping water where it shouldn’t, it can be both puzzling and worrying. Water in the wrong places can damage your walls, floors and even your AC unit itself. The good news? Most AC water leaks stem from common issues that you can often fix yourself with some basic know-how.

In this practical blog post, you’ll learn how to tell normal condensation from problematic leaks, identify the most common causes of dripping ACs, and follow step-by-step solutions to fix these issues. We’ll also cover when it’s time to call in professional help and share simple maintenance tips to prevent future leaks.

Why Water Leaks Occur

Your air conditioner creates condensation as part of its normal cooling process. As warm air passes over the cold evaporator coil, moisture in the air condenses into water droplets. In a properly working system, this water collects in a drain pan and flows out through a condensate drain line.

A small amount of water around the outdoor unit is normal. However, water pooling inside your property or dripping from the indoor unit signals a problem. The difference between normal condensation and a leak often comes down to where the water appears and how much there is.

Most leaks happen because something blocks the normal drainage path. Blocked drain lines, frozen coils, or damaged components can all turn normal condensation into a problematic leak.

Spotting the Warning Signs

Early detection of AC water leaks can save you from costly water damage. Watch for these signs:

What starts as a small drip can quickly turn into a big problem. Even minor leaks can damage drywall, flooring, and insulation over time. Persistent moisture also creates perfect conditions for mould growth, which can affect health and require expensive remediation.

Common Causes of a Dripping AC

Clogged Condensate Drain Line

The most frequent cause of AC water leaks is a blocked condensate drain line. This pipe carries water from your AC unit to the outside of your building or into a drain.

Over time, dust, dirt, and algae build up inside this line. The warm, moist environment of the drain pipe makes it an ideal breeding ground for slime and mould. As this growth increases, water flow slows and eventually stops completely.

When the drain line clogs, water backs up and overflows from the drain pan. You might notice water pooling around your indoor unit or water stains on the ceiling below an attic unit.

To prevent this issue, pour a cup of white vinegar down the drain line every few months. The mild acidity helps break down buildup and keeps the line flowing freely.

Frozen Evaporator Coil

When your AC’s evaporator coil freezes, it creates a secondary water problem. Ice forms on the coil when:

• Airflow is restricted (often due to a dirty air filter)
• Refrigerant levels are low
• The blower fan malfunctions

As the ice builds up, it blocks airflow further, making the problem worse. When the AC cycles off or the ice melts for any reason, all that frozen water thaws at once, often creating more water than the drain pan can handle.

A tell-tale sign of this issue is your AC blowing warm air (or no air) followed by a sudden appearance of water. You might also see frost on the refrigerant lines or hear water dripping when the unit cycles off.

Damaged Drain Pan

Your AC’s drain pan catches condensation from the evaporator coil. In older units, these pans can rust through. In any unit, they can crack from age or impact.

Look for these signs of drain pan damage:

• Visible rust spots or holes
• Cracks in the plastic
• Water dripping directly from under the unit rather than flowing to the drain

A damaged drain pan allows water to escape before it reaches the drain line, often resulting in water dripping in places it shouldn’t be. A quick inspection with a flashlight can reveal if your pan has developed problems.

Loose or Disconnected Drain Pipe

The constant vibration of an AC unit can loosen connections over time. This is particularly common at the joint between the drain pan and the drain pipe.

If these connections come loose, water leaks out at the joint instead of flowing through the pipe. You might see water dripping near the connection point or notice that the drain pipe has visibly separated from the unit.

Check all fittings to make sure they’re tight and properly sealed. PVC drain pipes should be firmly connected and, ideally, glued in place to prevent future disconnections.

Quick Troubleshooting Steps

Switch Off the AC

Before attempting any repairs, turn off your AC at both the thermostat and the circuit breaker. This will protect you from electrical hazards and prevent further water damage while you work.

If your AC is leaking a large amount of water, you should not continue to use it. Running a leaking unit can lead to electrical shorts and more extensive water damage.

Replace or Clean Your Filter

A dirty air filter is often the culprit behind AC leaks. When airflow is restricted, the evaporator coil can freeze, leading to water overflow when it thaws.

Locate your AC’s air filter and check its condition. If it looks dirty, replace it immediately. This simple step often resolves minor leaks by improving airflow and preventing coil freeze-ups.

For best results, replace your filter every 1-3 months during the cooling season. If you have pets or operate in a dusty environment, you might need to change it more often.

Clear the Condensate Drain

Clearing a clogged condensate drain line is often a quick fix for a leaking AC:

To test if your drain is clear, pour water into the access point and watch for it to flow out the end of the drain line. If water flows freely, you’ve solved the clog.

Inspect for Visible Damage

Use a flashlight to examine your AC’s components for damage:

• Look at the drain pan for cracks, rust, or holes.
• Check that the drain line is firmly connected to the drain pan.
• Inspect all connections and fittings for gaps or loose parts.
• Make sure the unit is properly mounted and level.

Minor cracks in the drain pan can be temporarily sealed with silicone or epoxy. However, cracked pans eventually need to be replaced for a permanent fix.

IMPORTANT DISCLAIMER: The following troubleshooting steps are general guidelines only. Always consult your AC unit’s specific manual before attempting any maintenance or repairs, as different models have unique requirements and configurations. Improper handling may void warranties or cause additional damage. If you’re unsure about any step, we recommend contacting a qualified professional.

When to Call a Professional

While many AC leak issues can be fixed with DIY methods, some situations require professional help:

If your AC continues to leak after you’ve cleaned the drain line and replaced the filter, deeper issues may be at play. A professional should check for the following:

• Low refrigerant levels (requires special equipment and certification)
• Faulty condensate pump (needs replacement)
• Internal component damage (complex repairs)
• Electrical problems (safety hazard)

You should also call a professional if you notice:

• Repeated leaks after DIY fixes
• Water-soaked insulation or water damage to your property
• The AC turns on but doesn’t cool properly (could indicate low refrigerant)

HVAC technicians use specialised tools, such as pressurised nitrogen, to flush drain lines completely, test refrigerant levels accurately, and access hard-to-reach parts of your system.

Preventive Measures to Avoid Recurring Drips

Regular Maintenance Checks

Preventing leaks is easier than fixing them:

These simple steps keep your AC running smoothly and prevent the most common causes of water leaks.

Professional Tune-Ups

An annual professional service goes beyond what most maintenance staff or property owners can do themselves:

• Technicians clean coils thoroughly
• They check refrigerant levels
• They test electrical components
• They flush the drain line completely

Professional maintenance typically costs £80-150, depending on what needs to be done, but it can save thousands in water damage repairs and extend the life of your AC.

If your system doesn’t already have a float switch, ask your technician about installing one. This safety device automatically shuts off the AC if water starts to back up in the drain pan, preventing overflow.

Monitor and Document

Pay attention to your AC system’s performance:

• Listen for unusual sounds (gurgling, dripping)
• Watch for changes in cooling efficiency
• Note any water or moisture, even small amounts

Keep a simple log of when you change filters, clean drain lines, and schedule professional service. This will help you stay on track with maintenance and provide useful information if you need repairs.

Conclusion: Wrap-Up

A dripping AC unit often signals a simple problem with a straightforward fix. By understanding the common causes, you can tackle many issues yourself:

• First, turn off your AC for safety.
• Replace or clean your air filter.
• Clear the condensate drain line.
• Check for visible damage.
• Call a professional for persistent problems.

Regular maintenance remains your best defence against AC water leaks. With proper care, your air conditioning system will keep your space cool without unwanted indoor puddles.

Remember that prompt action when you notice a leak can prevent water damage to your property. Don’t ignore even small drips – they often signal bigger problems on the horizon.

Need expert help with your AC issues?

At Controlled Climate Ltd, we have been providing trusted air conditioning services across Bristol, Bath, Weston-super-Mare, and surrounding areas for over 30 years. As REFCOM-accredited specialists, we make sure your system is repaired correctly and efficiently.

BOOK A FREE SURVEY or call us on 01174 528511 for emergency repairs and professional maintenance.

FAQs (Frequently Asked Questions)

• What causes the water to drip from my AC unit?
  Your AC creates condensation as part of the cooling process. When drainage systems become blocked or damaged, this water leaks out instead of draining properly.
• How can I tell if my AC condensate drain is clogged?
  Water pooling around your indoor unit or dripping from the ceiling below an attic unit often indicates a clogged drain. If your AC has a safety float switch, you might also notice it shutting off unexpectedly.
• Should I run my AC if it’s leaking water?
  No, you should turn off your AC if it’s leaking water. Continued operation can cause electrical hazards and water damage to your property.
• How often should I clean my AC drain line?
  During the cooling season, clean your AC drain line every three months by pouring a cup of white vinegar into the access point. Monthly cleaning may be necessary in very humid climates.
• Why does my AC freeze up and then leak water?
  Freezing occurs when airflow is restricted (often due to a dirty filter) or when refrigerant levels are low. When the ice melts, it overwhelms the drain system, causing leaks.
• Can I fix a cracked AC drain pan myself?
  Minor cracks can be temporarily sealed with silicone or epoxy, but a damaged drain pan should be replaced for a permanent solution.
• How can I prevent my AC from leaking in the future?
  Regular maintenance prevents most leaks: Change filters monthly, clean the drain line quarterly, schedule annual professional service, and install a float switch to shut off the AC if water backs up.
• Should I worry about a small amount of water under my outdoor AC unit?
  A small amount of water near the outdoor unit is normal, especially on humid days. However, water pooling inside your building or dripping from the indoor unit always requires attention.
• How long does it take to fix an AC water leak?
  Simple fixes like clearing a drain line take about 30 minutes. More complex repairs might require 1-2 hours of professional work.