What are the signs of an AC refrigerant leak?

What this symptom usually points to

Signs of an AC refrigerant leak are usually not the refrigerant itself being visible. What homeowners usually notice is the chain reaction: the system cools less, the indoor evaporator coil gets abnormally cold, ice forms on the coil or refrigerant line, and then water appears after that ice melts. If you have weak airflow together with ice, or puddling that started after poor cooling, that pattern fits low refrigerant far better than a simple drain issue.

What you can observe to separate likely causes

Water by itself near the indoor unit often points people toward a clogged condensate drain, but a refrigerant leak is more likely when the water shows up with warm supply air, long run times, hissing, or frost on the insulated copper line. Ice on the refrigerant line or indoor coil is a stronger clue than a small puddle alone. If moisture is reaching walls or ceilings in several rooms, the system may have frozen repeatedly and overflowed after thawing, or the air handler may be in an attic where meltwater can spread before it becomes visible indoors.

Location matters. Water near wiring or powered equipment is a stop-use situation because the immediate hazard is electrical, even if the root problem is low refrigerant. A small amount of water near the drain with no icing can still be a drain problem instead of a leak, but once you add weak airflow or visible ice, low charge moves much higher on the list.

Why this is different from other AC water problems

A refrigerant leak symptom page is about loss of charge in the sealed system, not just water management. The key difference is that the water is often secondary: the coil freezes because refrigerant pressure has dropped, then the ice melts when the system cycles off or is shut down. That is why homeowners often report the AC was cooling a little, then airflow faded, then they found water later.

What usually happens on a service visit

A qualified technician will usually confirm whether the coil is frozen, check operating pressures and temperatures, inspect the evaporator coil, line set, service valves, and outdoor coil for leak evidence, and use electronic leak detection and/or soap solution at likely points. If a leak is confirmed, the repair is not just adding refrigerant; the leak source should be repaired or the leaking coil or line component replaced before the system is recharged to specification. If the coil is iced over, thawing alone can take several hours before accurate testing and repair can be completed.

What affects repair cost

Cost depends mostly on where the leak is, what refrigerant the system uses, and whether the fix is a simple valve-core repair or a major coil replacement. Typical 2025-2026 US estimates are roughly $188-$607 for leak detection, about $188-$607 for minor accessible leak repairs such as a valve core or small joint, around $188-$607 or more for refrigerant recharge depending on type and amount, and often $1,450-$5,267+ for evaporator or condenser coil replacement. Older systems using R-410A or especially R-22 can push costs higher and sometimes make replacement more practical than major sealed-system repair.