Water dripping from your indoor unit is almost always a drainage problem — a blocked condensate drain or a dirty coil that ices and overflows — not a refrigerant leak. Here’s what causes it and how it’s fixed.
7 min read FreshDuct Melbourne Melbourne, Victoria
Water dripping from your indoor unit is almost always a drainage problem — a blocked condensate drain or a dirty coil that ices and overflows — not a refrigerant leak. Here’s what causes it and how it’s fixed.
Usually DrainageMost leaks are a blocked or mis-set drain
Don’t IgnoreWater can damage walls & wiring
Quick FixOften a clean & drain clear
Most indoor-unit water leaks come from a blocked condensate drain or a dirty coil that freezes and overflows — not a refrigerant leak. A service that clears the drain and cleans the coil resolves the large majority.
Why Is Water Dripping From My Split System?
If water is dripping from your indoor unit, the most common cause is a problem with the condensate drainage, not refrigerant. A split system removes moisture from the air as it cools, and that condensation is meant to drain away through a condensate line. When the drain blocks, or the unit can’t drain properly, the water overflows the tray and drips into the room. A dirty coil or filters can also cause icing that melts and overflows. The diagram above shows the usual suspects.
The Main Causes
Blocked condensate drain — the most common cause. The drain line clogs with dust, grime and biofilm, so condensation backs up and overflows. Dirty filters or coil — restricts airflow, the coil ices up, then melts and overflows the tray. Poor drainage slope — an install fault where the drain doesn’t fall away properly, so water sits and back-flows. Low refrigerant — can freeze the coil and cause melt overflow (this one also needs the gas issue fixed). Most leaks trace back to the first two.
What to Do Right Now
Turn the unit off to stop more water entering the room and protect the wall and any wiring below. Check and clean the filters (a quick DIY step). If the leak continues, it’s almost certainly the drain or coil and needs a service — clearing the condensate line and cleaning the coil. Don’t keep running a leaking unit, as water near electrical components and into walls causes real damage. See our cleaning guide.
Preventing Leaks
Regular servicing is the best prevention — it keeps the condensate drain clear and the coil and filters clean, which is exactly what stops the two most common leak causes. Cleaning or replacing filters every few months and having the system serviced periodically keeps drainage flowing and the coil clean. A well-maintained split system rarely leaks. See our service frequency guide.
When to Call a Technician
Call if the leak continues after a filter clean, if there’s a lot of water, or if you see ice on the indoor unit (which points to airflow or refrigerant issues). A technician will clear the drain, clean the coil, check the drainage slope, and confirm refrigerant levels — resolving the cause rather than just mopping up. Persistent leaks left unaddressed lead to ceiling, wall and electrical damage.
Frequently Asked Questions
Why is my split system leaking water inside?
Almost always because of a drainage problem, not a refrigerant leak. As a split system cools, it condenses moisture from the air, and that water is meant to drain away through the condensate line. When the line blocks with grime, or the coil ices up from dirty filters and then melts, the water overflows the tray and drips into the room. The fix is clearing the drain and cleaning the coil and filters — a standard service task.
Is a leaking split system dangerous?
It’s not immediately dangerous to you, but it can cause real damage if ignored — water dripping near the indoor unit’s electrical components, and onto walls, ceilings and floors, leads to staining, damage and potential electrical issues. Turn the unit off to stop the water, and have the cause addressed. It’s best not to keep running a unit that’s actively leaking.
Can I fix a leaking split system myself?
You can do the first step — turn it off and clean or replace the filters, which sometimes resolves a minor icing-related leak. But clearing a blocked condensate drain, cleaning the coil, and checking the drainage slope and refrigerant are technician tasks. If the leak continues after a filter clean, it needs a service to clear the drain and clean the coil properly.
Why does my split system leak only when it’s cooling?
Because cooling is when the unit condenses water from the air — the coil gets cold, moisture condenses on it, and drains away. In heating mode (reverse cycle) the indoor coil isn’t producing that condensation, so a drainage-related leak typically only shows up in cooling. This is a strong sign the problem is condensate drainage rather than anything else.
How do I stop my split system leaking in future?
Keep it serviced and the filters clean. Most leaks come from a blocked condensate drain or a dirty, iced coil — both prevented by regular servicing that clears the drain and cleans the coil, plus cleaning the filters every few months yourself. A maintained split system drains properly and rarely leaks.
Split System Problem or Quote? Talk to FreshDuct
Service, cleaning, repairs & installation across Melbourne — 7 days a week. Call or request a quote.
