Is some water around my AC normal?
A little condensation on the refrigerant lines, or right around the outdoor unit in hot weather, is normal, like a cold glass sweating on a warm day. Left alone, a real leak can damage walls, floors and ceilings and lead to mold, so the faster you find the cause, the better. These are not normal:
- Puddles under the indoor air handler
- Water dripping from the ceiling or walls near the air handler
- Steady dripping from the outdoor unit (more than light condensation)
- Water stains on drywall or flooring near the unit
Common causes of a leaking AC
1. Clogged condensate drain line
This is by far the most common cause. As your AC runs, it pulls moisture out of the air. That water collects on the evaporator coil, drips into a drain pan and flows out through the condensate drain line. Over time, algae, dust and debris clog the line, the pan overflows, and water ends up on the floor, in the walls or through the ceiling below. In the Treasure Valley’s dry, dusty climate, dust builds up in drain lines quickly, especially in homes that skip yearly maintenance.
Signs: water pooling directly under the indoor unit, a musty smell near the air handler, or an overflow safety switch that shuts the AC off entirely.
2. A frozen evaporator coil thawing
When the coil freezes from restricted airflow, low refrigerant or a dirty filter, it can look dry while the system runs. When the system shuts off, the ice melts all at once and makes more water than the pan and drain can handle. If water shows up after the AC turns off, a thawing coil is likely, and whatever made it freeze still needs to be fixed.
3. A damaged or rusted drain pan
The drain pan under the coil can rust through or crack in older systems, so water leaks out before it reaches the drain line. If your system is more than about 10 years old and leaks continue after the drain line is cleared, the pan may need replacing.
4. A disconnected drain line
Drain lines can work loose from their fittings, from vibration over time or after other work. Water then drains onto the floor or into the wall instead of out of the house.
5. Low refrigerant
Low refrigerant is one of the most common reasons a coil freezes, and refrigerant only runs low because of a leak. If water leaks keep coming back, a technician can check refrigerant levels and find the leak.
6. High indoor humidity
In very humid conditions an AC can make more condensation than the drain can handle. That’s rare in the Treasure Valley’s dry climate, but it can happen in unusually humid stretches or homes with a lot of indoor moisture.
What to do right now if your AC is leaking
Take these steps before you call. A clogged condensate line is one of the quicker repairs we handle, and catching it early prevents much more expensive water damage.
- Turn the AC off at the thermostat to stop more water and protect the equipment
- Put down towels or a bucket if it’s actively dripping
- Check your air filter and replace it if it’s dirty
- Check for a secondary drain pan (common with attic units); if it’s full, water may be close to the ceiling
- Don’t try to clear the drain with a wet-vac unless you know where the access port is: done wrong, it pushes the clog further in
How to prevent AC water leaks
Most condensate drain problems are preventable with routine maintenance. The Drake Duck Club Heating & AC plan includes a yearly cooling visit that covers the condensate drain and a coil pan treatment.
- Schedule a yearly AC tune-up: the drain line is flushed, the coil cleaned and the pan checked
- Change your air filter every 30 to 90 days, depending on your home
- Ask about drain pan treatment tablets that slow algae growth
- Ask about an overflow shutoff switch if your system doesn’t have one