Air Con Leaking Water Indoors
Indoor air conditioning units produce condensate as a normal part of cooling, in exactly the same way a cold drink sweats on a warm day. That water is supposed to run away through a small drain pipe, usually out through an external wall alongside the refrigerant pipework. When you see water indoors, something in that drainage path has gone wrong.
Left alone, a dripping unit can damage plasterboard, ceilings, and flooring, so it's worth addressing quickly even though the cause is usually straightforward.
What usually causes it
- Blocked condensate drain pipe, often from algae or dust build-up inside the pipe
- A drain pipe with a dip or 'belly' in it where water pools and can't drain by gravity
- A cracked or displaced condensate tray inside the indoor unit
- Ice forming on the coil and then melting faster than the drain can cope with
- On units with a condensate pump, a failed or jammed pump
Safe checks before calling anyone
Look outside for the end of the drain pipe, usually a small white or grey pipe near the outdoor unit or lower down the wall. If it's dry when the unit is dripping indoors, that's a strong sign of a blockage somewhere along its length.
Check the unit is mounted level, as even a slight tilt can send condensate the wrong way inside the casing. Beyond that, we'd avoid poking anything into the drain pipe or dismantling the indoor unit, since the tray and coil are easy to damage.
Why a professional clear or repair is worth it
Clearing a blocked condensate line properly usually means using a vacuum pump from the outdoor end rather than pushing a blockage further in, and checking the pipe run for the low points that cause repeat blockages. If the tray itself is cracked or the pump has failed, that's a parts replacement job rather than a clean.
We'd also check whether icing on the coil is the underlying cause, since that points to a refrigerant or airflow problem that will keep causing drips until it's fixed.
On the day
We isolate the unit, inspect the drain pan and pipe run, and clear blockages using a vacuum method suited to the pipe size. Where the pipe has a poor fall or an awkward route, we'll flag it, since a badly installed drain will keep causing problems regardless of how often it's cleared.
Reducing the chance of it recurring
- Have the condensate line checked as part of an annual service, not just the filters
- Keep an eye out after long idle periods, when algae build-up is most likely
- Address any icing on the coil promptly, as melting ice is a common trigger for overflow
FAQs
Common questions
Is a leaking indoor unit dangerous?
It's not an electrical safety risk in most cases, but ongoing water ingress can damage plasterboard and flooring, so it's worth fixing promptly.
Can I just put a towel under it until someone comes out?
Yes, that's a sensible short-term measure, alongside switching the unit off if the drip is heavy, to limit further water damage.
Why does this happen more in summer?
Higher condensate volumes from heavier cooling loads make existing drainage restrictions more likely to overflow.
Will this happen again after it's cleared?
If the underlying cause, such as a poor pipe fall, isn't addressed, blockages can recur. We'll tell you if that's a risk on your system.
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