Central A/C & heat pumps

Water leaking from the outdoor AC unit

Some dripping from the outdoor unit is normal during humid weather, but a heavy or constant leak usually means the condensate drain or a coil issue.

Difficulty
Easy
Time
15–20 minutes to assess
DIY cost
$0
Pro cost
$100–$300

Symptoms

  • Puddle or steady drip forming under or near the outdoor unit
  • May be worse during humid weather
  • Amount of water seems more than typical condensation

Likely causes

  • CommonNormal condensation during humid weatherSome dripping from the unit is expected on hot, humid days and isn't a problem by itself.
  • CommonIndoor condensate line routed to drain near the outdoor unitSome installations route the condensate drain to daylight near the condenser, which can look like a leak from the unit itself.
  • PossibleIce on the coil melting after a freeze-upIf the system recently iced up, melting ice can create a temporary heavy drip outside.
  • Less commonDamaged pan or coil inside the outdoor unit (heat pumps)On heat pump systems that also handle defrost cycles, a damaged internal pan can leak more than normal.

What to do

  1. Note whether the water is coming from a nearby condensate drain pipe or directly from under the unit's cabinet.
  2. Check whether the leak coincides with hot, humid days, which points to normal condensation.
  3. If the indoor coil recently had ice on it, allow time for it to fully melt and see if the outdoor leak stops.
  4. Look for a small drain hole at the base of the outdoor cabinet, which is a normal factory-designed drip point for defrost water on heat pumps.
  5. If the amount of water seems excessive or doesn't match weather or a recent freeze-up, have a technician inspect it.
  6. Clear away any grass or debris blocking normal drainage at the base of the unit.

When to call a pro

Call an HVAC technician if water from the outdoor unit is heavy, constant, and not explained by humidity or a recent ice thaw.

Safety

Generally low risk

Generally low risk for a careful person. Stop if anything looks different from what this guide describes.

Related guides

Operator provides AI-generated troubleshooting information. It can be wrong. For safety-critical, electrical, gas, structural, medical, automotive safety, or other high-risk problems, consult a qualified professional.