Exterior air conditioning units are built to withstand many of nature’s elements—rain, snow, wind, even hail. It’s copper, aluminum, steel and rubber can endure almost anything. Excluding fire, flood water is the rare exception that can immediately ruin or significantly shorten the life of your air conditioning system. But how do you assess a flooded AC unit and determine next steps?

When thinking about floods and AC units, the first question that usually comes to a homeowner’s mind is how many inches of water can his/her AC unit withstand without incurring significant damage. We’ll dive into some of the specifics this question involves, but it is generally accepted an AC unit can take on 12”-16” of water without being in danger of break down. Another general rule of thumb is an external air conditioning unit can withstand the level of flood water until it reaches its lowest positioned electrical component.

Electronic components are, by far, an air conditioning unit’s Achilles heel in flooding conditions. While these components are protected from hail, ice storms and wind strewn debris, they are vulnerable to being submerged in flood water.

Okay, this is all good information, but what steps can I take before and after a storm to minimize flood damage to my external unit and overall air conditioning system?

Preventative Actions To Protect AC Unit Before the Storm:

  • Turn off breaker at the fuse box
  • Turn off indoor thermostat
  • Surround unit with sandbags if feasible

Assess Flooded AC Unit After the Storm

  • If not already done, turn of breaker at fuse box
  • If not already done, turn off thermostat
  • Clean coils in outside unit from the inside
  • Check electrical components for corrosion
  • Check condenser motor fan seal
  • Clean compressor terminals
  • Check wires and connectors for corrosion
  • Check refrigerant lines
  • Check all potentially affected duct-work
  • Replace water-contaminated filters and insulation
  • Allow air conditioning system to dry out
  • Run system continuously 48-72 hours to remove remaining contaminants


Church Services HIGHLY recommends you call one of our trained HVAC professionals to perform the above mentions tasks. 713-722-5000