Why Does Water Come Out From A Split AC?

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Why Does Water Come Out From A Split AC?

Many times the phone will ring at Kotz Heating, Cooling & Plumbing and a panicked Waterford, MI or Oxford, MI homeowner will ask, “My air conditioner is leaking. Where is the water coming from?” Many people are astonished to learn how much water an air conditioner removes as it cools the hot and humid summer air. It’s generally from five to as much as 20 gallons of water every day.


As I indicated the water is moisture that is taken out of the air. A split AC system has an outside compressor and an indoor air handler which includes the evaporator coil which has refrigerant flowing through it. The coil cools the warm air blown across it. Because cool air can’t hold as much moisture, condensation forms on the coil, just like it does on your glass of ice water. The moisture, also called condensate, drains into a pan then into a drain line which usually carries the water outside the house.


When the system is working correctly you should not see any water coming from your air conditioner. If you do see water, then something is wrong, and it needs to be repaired quickly. The water can quickly cause damage. With that in mind, here are a few common causes for water leaks:

  1. Clogged drain line—This is the most common problem. The water drain line can become clogged with dust, dirt, mold, or sludge. Instead of draining away, the water backs up and overflows the drain pan. You might be able to remove the clog using a wet/dry vac but it’s safer to have a professional do the job for you. NOTE: You can reduce the odds of a clog by pouring a cup or two of bleach water down the drain line a couple times a year.
  2. A leaking drain pan—This is much more likely with older split AC systems. The drain pan may be damaged or rusted through, allowing the water to leak out instead of flowing to the water line.
  3. Condensate pump is broken—If your air handler is installed in the basement there is a very good chance you have a small electric pump. It forces the water up and outside the house. If the pump stops working the water has no place to go except the basement floor.


Many times, a clogged air filter or low refrigerant level causes the evaporator coil to get too cold. The condensation freezes and forms ice. To be clear, this isn’t a problem with the condensate drain system. It’s caused by a problem with the air conditioner itself. The ice has to melt before our Kotz technicians can repair the problem. The melting ice can often cause a water leak.


Any sign of water coming from your air conditioner should be taken seriously and you should call Kotz Heating, Cooling & Plumbing to schedule an appointment. The problem needs to be identified and fixed before the water damages your Waterford, MI or Oxford, MI home or the air conditioner.