Why Is My AC Leaking Water?
Your AC pulls water out of the air, and that water is supposed to run away down a drain. Water on the floor usually means the drain is clogged, the pan under the unit has rusted through, or a frozen coil is melting. Switch the thermostat to OFF to stop new water, then look in the drain pan.
What makes an AC leak water?
Clogged drain line
Slime, dust, and dirt build up inside the drain pipe until water backs up into the pan and spills over. This is the most common cause of water indoors. You can check the pan and the safety switch. Clearing and treating the line is a service visit.
Technician repairDirty filter freezing the coil
A blocked filter starves the coil of air, so the coil freezes. When that ice melts, it sheds more water than the pan and drain can take. Changing the filter is safe to do yourself, and it stops the cycle from repeating.
Safe to check yourselfFrozen coil melting between cycles
When the coil has frozen from low refrigerant or poor airflow, the ice melts every time the system shuts off. All that meltwater floods the pan and shows up as puddles. The ice is only a symptom. The cause needs a technician.
Technician repairFailed water pump
Systems in basements often have to push the water uphill through a small pump. When the pump dies or its float sticks, the tank fills and spills over. You might hear it running all the time, or never. Replacing it is technician work.
Technician repairRusted or cracked drain pan
The pan under the unit rusts with age, mostly on systems past ten to fifteen years. A rusted pan drips even when the drain is clear. Attic units usually have a second pan below, and water in that one means the first pan or the drain has already failed.
Technician repairLoose drain fitting
Age and shaking can loosen the plastic fittings where the drain pipe meets the pan. Water then drips at the joint instead of running to the drain. Sealing it properly, and checking that the pipe still slopes the right way, is our job.
Technician repairWhat can you check yourself?
- Switch the thermostat to OFF so the system stops making new water.
- Look for a small safety switch on the drain pan or the drain pipe and see whether it has tripped.
- Check whether the pan under the indoor unit is holding standing water.
- Change the filter if it is dirty. A blocked filter can freeze the coil and flood the pan.
- Mop up the water and keep it away from wiring, outlets, and the furnace cabinet.
Safety note: Water and electricity are a dangerous mix. If water has reached wiring, outlets, or the furnace cabinet, leave the system off and call.
When should you call for repair?
Call when the pan is holding water, when the water comes back after a new filter, or when you see ice on the copper lines. Call before you restart the system if water has reached flooring, drywall, or anything electrical. A clogged drain does not clear itself, and every cooling cycle adds more water. A service visit clears the line, treats it so the slime does not come back, and checks that the pan and safety switch are doing their jobs.
Montgomery Village was planned all at once in the 1960s and 70s, and the mechanical closets show it. There is room for the equipment and very little else, so the drain line has no margin at all. A small slope problem or a bit of slime backs water up quickly. The layouts in Whetstone and Stedwick repeat, so a drain fault we have traced in one closet usually points straight to it in the next. Act on the first puddle.
Related questions
Is an AC leaking water an emergency?
It is urgent, but it is usually not an emergency. Switch the system to OFF to stop new water, protect the floor, and keep the water away from anything electrical. The equipment is rarely hurt by the water. Ceilings, flooring, and finished basements are. Book a repair before you run it again.
How much water should an AC drain in a day?
On a humid summer day a central AC commonly pulls five to twenty gallons of water out of the air. All of it should leave through the drain. Steady dripping where the drain pipe ends outside is normal and healthy. Water anywhere else means the drain path has a problem.
Why does my AC leak only on humid days?
Humid days make far more water, so a half-clogged drain that keeps up on a dry day falls behind when the air gets muggy. The pan fills and the overflow shows up only during those stretches. That pattern is an early warning. Clearing the line now heads off a full blockage in the hottest weeks.
Can a clogged drain shut my AC down?
Yes. Most systems have a small safety switch that cuts the power when the pan backs up, so the water cannot overflow. If your AC stopped on a humid day and the thermostat looks fine, check the pan for standing water. The system stays off until the drain is cleared and the switch resets.
If water keeps showing up around your AC, call Mora Heating & Air and we will clear the cause, not just the puddle.
Or tell us what your system is doing
Send us the details and we will call you back. If the house is very hot or very cold right now, calling is faster.