Your air conditioner leaks water when its condensate drain line clogs, its pan cracks or its float switch fails. Turn the system off at the thermostat, then find where the water is. Lane County homes in Eugene and Springfield reach us at (541) 461-2101. Salem and Keizer homes in Marion County dial (503) 581-9982. Both lines stay open around the clock.
Your air conditioner pulls moisture out of your indoor air as it cools. It has to send that water somewhere. Most leaks come from a clogged line, which costs little to clear. The ceiling it soaked costs more. Start with the first question. A running system makes every leak worse.
Is it OK to run my AC if it’s leaking water?
No, turn your AC off when it leaks water, because a running system keeps filling the pan and can soak a ceiling in an afternoon.
Work through these checks in order, and stop at any step you are not comfortable doing yourself.
- Switch the thermostat to off. Switch off the system’s breaker too if water is close to electrical parts.
- Look at the air filter. A clogged filter starves the coil of air and can ice it over. Check it.
- Look at the drain pan under the indoor coil. Standing water means the line is blocked or the pan is cracked.
- Check the outdoor end of the drain line. A dry line while the pan is full points to a clog.
- Look for ice on the refrigerant lines or coil. Ice means trouble.
- Call us if the leak returns, ice is present, or the water is near wiring.
We check the thermostat setting before any hardware. It’s quick. A dirty filter costs the least to fix of any cause here. We check it first. Then we inspect the coil for ice. You can follow a schedule for how often to change the air filter. Once the system is off and the filter is clear, ask where the water was supposed to go. That’s the drain path.
Where does AC condensate go, and where does it back up?
AC condensate drips off the evaporator coil into the primary pan, then runs down the drain line to the outdoors.
The cold evaporator coil pulls moisture from your room air, and the moisture condenses into drops. The primary pan catches them. A drain line carries the water away through a trap on some systems and out of the house. Where the line cannot run downhill, a condensate pump lifts the water instead.
Two parts guard the path. A float switch sits in or near the pan. It shuts the cooling off when the water rises. A secondary pan under the unit catches what the primary pan misses. A cleanout tee is a vertical access port on the line. We clean the line through the tee without taking it apart. We check the drain pan while we are there.
Block the path at any point and the pan fills. Simple. The first sign you notice is usually a wet pan, a musty smell or a system that quits. Watch for those. We inspect the pan, the trap and the outdoor end of the line on every leak call, in the order the water travels. Which of those signs do you see?
Where is the water, and what does it mean?
The place where the water appears points to the cause, so match what you see to the first row that fits.
| Where the water is | Most likely cause | Normal? |
|---|---|---|
| Pan or floor under the indoor unit | Clogged line, cracked pan or tripped float switch | No |
| Ceiling stain below an attic air handler | Overflowing primary pan or blocked line | No |
| Puddle around a crawlspace or basement unit | Same causes, found late | No |
| Water dripping from a supply vent | Frozen coil thawing, or condensation in the duct | No |
| Puddle at the outdoor end of a drain line | Normal condensate discharge | Yes |
| Drips under a heat pump outdoors in winter | Defrost cycle | Yes |
| Water around a high-efficiency furnace | Condensate trap or line problem | No |
Indoor water in your home is never normal. Never. Our technicians check the pan and the drain line before they blame anything else. We check the pan first, then the line, then the switch. So what actually breaks?
What causes an AC to leak water?
Seven causes account for most AC water leaks, and a clogged condensate line leads the list.
- Clogged condensate line. Algae, dust and sediment build into a slime that backs the water up. Most leaks come down to this one. We clean the line first.
- Cracked or rusted drain pan. Older steel pans rust through. The water never reaches the drain. We inspect the pan for cracks and rust spots.
- Tripped or failed float switch. The switch shuts cooling off when the pan fills. If it trips, the system quits. If it fails, nothing stops the overflow. That’s the danger. We test the switch before we restart a system it shut down. A system that won’t start can be this switch. See our AC that won’t turn on troubleshooting guide.
- Failed condensate pump. Where the drain cannot run downhill, a small pump lifts the water out. When it quits, the reservoir overflows. We check the pump and its float on any unit that lifts its water.
- Frozen coil thawing. Ice melts faster than your pan can handle. Too fast. Read how to fix a frozen evaporator coil before you restart the system. We check airflow and the filter before we restart a thawed system.
- Dirty filter. It chokes airflow and sets up the freeze above. We check it on every leak call.
- Disconnected or sagging line. A joint pulls apart. Or a section sags and holds water, which then spills at the joint. We inspect the full run of the line for sags and loose joints.
Any one of these can overflow a pan you never look at. Many Oregon air handlers sit in places like that. Hidden pans fail quietly.
Why is my attic or crawlspace air handler leaking through the ceiling?
An attic air handler leaks through the ceiling when its primary pan overflows and the water soaks the insulation and drywall below.
Many Oregon homes put the air handler in a crawlspace or attic. Out of sight. We service units in both spots. A basement unit gets the same inspection. Nobody checks the pan there. A slow overflow can run for days before you notice it. The water crosses the platform, soaks the insulation and then stains the drywall. By the time you see the stain, the damage in your ceiling has been building for a while.
A float switch is the safeguard that matters most in these spots, because it cuts the cooling before the pan spills. A secondary pan under the unit adds a second catch. If your unit sits somewhere you rarely look, we check whether it has either one. Our technicians inspect the platform and both pans on an attic call. The EPA says wet materials need to dry within 24 to 48 hours to prevent mold growth. That’s a short window for a hidden leak. Our post on common air handler problems shows what else goes wrong in these cabinets.
Is it normal for my outdoor AC unit or heat pump to drip water?
Yes, a drain line dripping outdoors on a hot afternoon and a heat pump dripping in winter are both normal.
The outdoor drain line is the system doing its job. It needs nothing from you. We check the defrost cycle on any winter call about a dripping heat pump. A heat pump melts frost off its outdoor coil during the defrost cycle, so it drips and steams in cold weather by design. Worry when water pools around the outdoor unit while the system sits idle, or when the fluid looks oily. Call James for either. We inspect the outdoor coil for frost and the end of the drain line, and we test the system before we leave.
Why is water leaking around my furnace?
A high-efficiency furnace leaks water when its condensate trap or drain line cracks or clogs, because it condenses water vapor out of its flue gases.
The U.S. Department of Energy’s Building America guide says these furnaces reach an AFUE of 90% to 98% and need a suitable condensate drain. A cracked trap or blocked line leaves water at the furnace in January. That surprises people. We service high-efficiency furnaces as well as air conditioners. We inspect the trap, the line and the safety switch on a furnace leak call. Then we clean the trap and test the drain line.
How do I unclog an AC drain line?
Unclog an AC drain line by shutting off power and pulling the clog out with a wet-vac at the outdoor end of the line.
- Turn off the system at the thermostat and the breaker.
- Find the line’s outdoor end, usually a PVC pipe near the foundation.
- Hold a wet-vac hose against the end with a rag sealing the gap. Run it for a few minutes.
- If the line has a cleanout, pour distilled white vinegar into the access port. Use it only if the manufacturer’s manual allows it, since some makers advise against any cleaner.
- Flush with water and restart. Done. We run water through the line after we clean it to confirm the drain flows.
Do not force a wire down your line. Don’t. It can puncture the pipe or push the clog deeper. Skip bleach unless the manual calls for it. Read the manual. If the water backs up again within days, the blockage is deeper or the pan is damaged. Stop there. Call us. We pull the clog with a wet-vac at the outdoor end the same way. Then we check the coil for ice and the pan for cracks. Now the cost.
How much does it cost to fix an AC water leak?
AC water leak repairs run from about $75 for snaking a drain line to $1,000 for a condensate pump replacement in national cost guides.
These ranges come from national cost guides, not from James Heating and Air Conditioning. Access, pipe length and the unit’s location change every job, so we quote a firm price after we inspect your system.
| Repair | Low | Average | High | Source |
|---|---|---|---|---|
| Drain line snaking | $75 | $120 | $200 | Pick Comfort, May 2026 |
| Wet-vac clearing plus coil check | $90 | $140 | $250 | Pick Comfort, May 2026 |
| Drain line replacement, per 10 feet | $40 | $100 | $240 | PickHVAC, May 2026 |
| Drain pan replacement | $150 | $350 | $700 | Pick Comfort, May 2026 |
| Float switch add-on | $40 to $120 | n/a | n/a | Pick Comfort, May 2026 |
| Secondary pan | $200 | $450 | $900 | Pick Comfort, May 2026 |
| Condensate pump replacement | $150 | $400 | $1,000 | PickHVAC, May 2026 |
If your ceiling has already soaked, you add drywall and paint on top of any of these. We check the insulation and the ceiling below for moisture before we quote the repair.
Why does my AC leak in a dry Eugene summer?
Your AC leaks in a dry Eugene summer because condensate comes from the moisture inside your house, not from the outdoor humidity.
The University of Oregon’s climate page, citing NOAA data, calls July and August “very dry”, with average rainfall of 0.51 inches in July and 1.08 inches in August over a 30-year period ending in 1993. Dry air outside does not stop your cooling system from wringing water out of the air inside. It still runs. We test the drain with water before the first heat wave when you book a visit.
What the climate does do is leave your AC off for much of the year. Algae and debris sit in the line, then the first heat wave pushes a full load of water through it. A clog that formed in October shows up in July. Plan ahead. Book a preventative maintenance visit before the first hot week and ask us to look at the drain line. We inspect the line and clean it when you ask.
Call James if the leak returns, ice appears or water reaches wiring
Call if you cleared the line and the leak came back. Call if there is ice, a failed pump, a rusted pan or a ceiling stain. We handle AC repair for these across Eugene, Springfield and Salem. We diagnose the cause first. You get a quote before we start.
Eugene, Springfield and Lane County: (541) 461-2101. Salem, Keizer and Marion County: (503) 581-9982. Both lines run 24 hours a day for emergencies. We dispatch leak calls day and night. James Heating and Air Conditioning, CCB #47396, has served the Willamette Valley since 1983.
Frequently asked questions
Why is water coming out of my AC vent?
Usually a frozen coil is thawing and overflowing the pan, or a blocked line has filled the pan until water reaches the air handler cabinet. We check the filter and the coil for ice on a dripping vent call. Check them yourself first, then call us if the vent keeps dripping.
Can a frozen coil cause a leak?
Yes. When the ice melts it produces more water than the pan and line can carry, and the overflow lands indoors. A dirty filter or low airflow is the usual trigger, and we check airflow before we restart the system.
Is a leaking AC an emergency?
It is urgent, because the water can damage ceilings, flooring and drywall the longer it runs. Turn the system off. We diagnose the cause and we repair the line, pan or switch behind it.
Does a leaking AC mean I need a new unit?
Usually not, because most leaks trace to a drain line, pan or float switch. The U.S. Department of Energy’s Building America guide says to replace a system when repairs cost more than half the cost of replacement. We quote the repair and the replacement in writing.
Will homeowners insurance cover an AC leak?
Policies differ. Many cover sudden water damage to the home but not the air conditioner itself, and some exclude slow leaks. Check your policy and photograph the damage before cleanup.
Why is my outdoor AC unit leaking water?
A drain line dripping outside on a hot day is normal condensate. A heat pump dripping in winter is the defrost cycle. Water pooling around the outdoor unit when the system is idle, or oily fluid, is not normal, so call James.
