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AC dripping water indoors

AC dripping water indoors

Why is My AC Dripping Water Indoors? A Complete Troubleshooting and Repair Guide

Walking into a room and finding droplets of water dripping from your air conditioning vents can certainly be alarming. Your mind may race with questions like “What’s causing this?”, “Is this normal?” or “How can I fix it?”. Rest assured, with some diligent troubleshooting and targeted repairs, you can solve an AC drip problem.

In this comprehensive guide, we’ll cover all aspects of diagnosing and fixing an air conditioner that is leaking water inside your home. You’ll learn what causes drips, where to check for leaks, how to troubleshoot the issue step-by-step, DIY repair tips, when to call an HVAC pro, and preventive maintenance to stop AC drips before they start. Arm yourself with knowledge and take control of the situation with the right information.

What Causes an AC Unit to Drip Water Inside the House?

Air conditioners are designed to remove heat and humidity from your indoor air. As warm interior air passes over the cold AC coils, this condenses moisture out of the air as liquid water. The water, or condensate, drips down into a drain pan below the coils. It then flows out of the house through a plastic drain line.

Problems arise when something obstructs or overwhelms this moisture drainage system. Here are the most common culprits for water dripping inside from an AC:

Clogged Drain Line: The primary cause of most AC water leaks is a blocked drain line. Dirt, algae, mold or debris can obstruct the plastic drain pipe. This prevents condensate from exiting outside.

Drain Line Leak: Cracks or disjointed segments in the drain line create openings where water drips out before reaching the outdoor outlet. This causes leaks inside the house.

Drain Pan Overflow: The drain pan underneath the coils collects condensate. If dirt clogs the drain opening or the float switch fails, the pan can overflow, sending water dripping into the indoor space.

Low Refrigerant: Not enough refrigerant impairs the AC system’s ability to properly cool and remove moisture. This leads to excessive condensate dripping indoors.

Frozen AC Coils: In cold weather, ice can buildup on the coils when they drop below freezing. The water leaks inside as the ice melts during defrost cycles.

Humid Climate: An AC in hot, muggy climates has to work overtime to condense large amounts of moisture from humid indoor air. This puts strain on the drainage system.

Improper Installation: If the outdoor unit or indoor coils lack proper slope, gravity cannot effectively draw away condensate. Water can overflow instead.

Failed Condensate Pump: Many ACs rely on a small pump to push the condensate through the drain line. If this pump fails, water leaks out inside the building.

Identifying where the excess water is coming from and why drainage is disrupted is the key first step toward diagnosing and repairing a drippy AC system.

Where Does the Leaking Water Come From in an AC?

When assessing an air conditioner that drips water inside, it helps to know the source of that condensate inside the system. The two main sources are:

AC Condensate: This is water condensed out of humid interior air by the cold evaporator coil. Warm air passing over the chilled coils turns to liquid water, like dew forming on grass in the morning.

Melted Coil Ice: In extremely cold weather, the AC coils can drop below freezing and build up a layer of ice. As the frozen coil cycles into defrost mode, the ice melts, sending water dripping into the indoor space.

Both condensate and melted ice should drain through the exit line outside. Finding where drainage is obstructed prevents proper removal, causing overflow into the house.

Signs Your AC is Dripping Water Indoors

Detecting the signs of an AC drip problem quickly can help minimize water damage. Be on the lookout for these common indicators:

  • Water Dripping from Vents: Hearing the “plink” of water hitting carpet and seeing droplets fall from the vents are clear signs of a clogged drain line.
  • Wet Floor Underneath Vents: Water dripping outside the drain system collects on the floor or soaks the carpet underneath the vent openings.
  • Water Stains on Walls and Ceilings: Overflow water leaves telltale water marks on drywall and ceiling surfaces near vents as gravity pulls it downward.
  • Musty Damp Smell: Excess moisture in the air carries an unpleasant odor. Stagnant water from the AC grows mold and bacteria.
  • Mold or Mildew Growth: Along with musty smells, consistently wet surfaces foster fuzzy black or white mold growth.
  • Pool Under Outdoor Unit: Check the ground below the exterior condenser. A puddle or pool indicates a drain line leak outside the house.
  • Dripping in Attic or Crawlspace: Water may drip in the attic or crawlspace if the clog occurs in that section of the vertical drain line.

Once you confirm leaky drip signs, it’s time to play HVAC detective and diagnose the root cause.

How to Troubleshoot an AC Dripping Water Inside the Home

Finding the specific reason an air conditioner is leaking water indoors involves methodically troubleshooting the condensate drainage system from start to finish. Here are the steps:

  1. Inspect Entire Drain Line: Carefully examine the plastic drain piping from the indoor coils all the way to the outdoor outlet for obstructions. Look for disconnected segments or cracks that could cause leaks.
  2. Flush the Drain Line: Use water, compressed air or a drain snake to force out any dirt, algae, mold or debris clogging the line. Confirm the water flows freely out the exit point after flushing.
  3. Remove and Clean Drain Pan: Take out the drain pan and clear any sludge or dirt buildup around the drain opening so condensate can flow out freely. Check for cracks.
  4. Test the Drain Pump: If equipped, unplug the small electric condensate pump. Check if it pumps water when plugged back in and working. Replace any faulty pump.
  5. Check Refrigerant Levels: Using HVAC gauges, check the refrigerant charge. Low refrigerant impairs cooling ability leading to AC coil freeze ups and drips during defrost.
  6. Inspect the AC Coils: The evaporator coils should be clear, not caked in ice buildup. Also verify the coil is correctly angled downward to promote drainage.
  7. Monitor the System: Observe the AC operating to identify overflowing drain pans, unusual ice formations or obvious water leaks.

By methodically inspecting each component, you can zero in on clogged pipes, broken pumps or freezing coils as the culprit.

Repair Solutions for an AC Dripping Water Inside

Once the specific problem is identified through troubleshooting, you can take targeted steps to fix the issue and keep condensate contained in the drainage system not dripping loose inside your home. DIY repair solutions include:

  • Snaking the Drain Line: Use a flexible auger or compressed air to open the blocked drain line so water can flow out normally.
  • Adjusting Drain Line Slope: Any sections sagging down instead of sloped out can hold water. Straighten as needed for better flow.
  • Tightening Pipe Connections: Check fittings between pipe segments and tighten any loose connections where water might drip out.
  • Replacing Damaged Piping: If cracking, holes or breaks are found, replace the leaky parts of the drain line.
  • Cleaning the Drain Pan: Remove accumulated gunk and debris so condensate can flow out the drain port as designed.
  • Installing a Float Switch: This shuts off the AC if water rises too high in the pan, preventing overflows.
  • Replacing Faulty Drain Pump: If a bad condensate pump caused the indoor leak, install a new pump.
  • Adding Backup Drain Pan: An additional deeper pan provides emergency backup drainage in case the primary pan clogs or overflows.
  • Recharging Refrigerant: Properly recharge the AC system if low refrigerant levels led to coil freeze ups and drips during defrost cycles.
  • Adjusting Coil Angle: Ensure the evaporator coil is tilted down toward the drain port to use gravity to pull water out.

Solving an AC drip involves finding and fixing the specific mechanical issue, whether it’s unclogging pipes, replacing faulty parts or adjusting components.

Calling in Professional Help with an AC Leak

While many basic AC leaks and drips can be tackled DIY, more complex issues often require a professional’s expertise. Call an HVAC technician for help if:

  • There is a Refrigerant Leak: Only certified technicians have the tools and skills to properly diagnose and repair refrigerant leaks.
  • Drain Line Access is Difficult: Getting to drain lines in walls or cramped spaces often requires pro equipment and skills.
  • Electrical Issues are Suspected: It’s always safest to have a qualified technician handle any electrical repairs or testing.
  • DIY Efforts Fail: If you’ve tried unsuccessfully to fix the leak yourself, avoid frustration and call the pros.
  • There is Mold Contamination: HVAC professionals know how to safely handle mold with proper containment and remediation.

You’ll have peace of mind getting expert assistance efficiently solving an ongoing or complex AC drip issue.

Preventing AC Leaks and Drips

Routine maintenance provides the best way to avoid problematic condensate leaks and drips from your air conditioning system. Prevent issues with these proactive steps:

  • Change Filters Regularly: Clogged, dirty filters reduce airflow leading to excess moisture buildup in the system.
  • Annual Drain Line Cleaning: Flushing debris from the drain line maintains unobstructed condensate flow.
  • Install a Overflow Float Switch: This automatically shuts off the AC if the drain pan fills up too high with water.
  • Insulate Ductwork: Prevent drips due to condensation on ducts in hot humid climates by insulating all ductwork.
  • Monitor and Maintain Refrigerant Levels: Low refrigerant reduces cooling capacity and leads to ice and drips. Stay on top of refrigerant charge.
  • Maintain Proper Drainage Slope: Keep drain pans and drain lines aligned properly to use gravity, not fight it.
  • Clean Coils and Drain Pans: An annual deep cleaning prevents muddy buildup that can clog components.

Make drip-free AC operation a priority by integrating preventive maintenance into your home care routine.


While finding water raining down from your air conditioning vents can certainly get your heart racing, resolving an AC drip or leak issue does not have to be overwhelming. Arm yourself with information on common causes, smart troubleshooting, repair solutions and preventive steps. Address problems promptly and don’t hesitate to call a professional when needed. With determination and diligence, you can banish excessive condensate drips for good and keep your air conditioning system – and your indoor space – cool, comfortable and dry.

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