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Why Is My AC Unit Leaking Water Inside the House?

An indoor AC unit leaking water usually means a clogged condensate drain line or a frozen evaporator coil. Clearing the blockage stops the leak.

Category:HVAC
Difficulty:Moderate
Time:1 hour
Success:50%
Updated:May 29, 2026

quick_referenceQuick Answer

For Why Is My AC Unit Leaking Water Inside the House?, start with "Locate the condensate drain line": Find the PVC pipe coming from your indoor air handler. It usually exits near the outdoor unit or into a floor drain. Stop DIY if the drain pan is rusted through or cracked. This is listed as a moderate recovery and usually takes about 1 hour.

verifiedGuide Snapshot

Repair areaHVAC
Estimated time1 hour
DifficultyModerate
Stop conditions3

Last updated May 29, 2026. Review the stop conditions before continuing.

account_treeRecovery State

DeviceAc Unit
Current stateWater Leak
Specific stateIndoor Leak
Failed stepCondensate Drain Clog
Likely failure typeBlocked Path
DIY boundaryDIY recovery first
paymentsCost decision

help1. Understand the Problem

Your air conditioner produces condensation as it cools. Normally, this water drains outside through a plastic line. If that line gets clogged with algae or debris, water backs up and overflows the drain pan, leaking into your home.

build_circle2. Try This First

Best First Step
Locate the condensate drain line

Locate the condensate drain line

Find the PVC pipe coming from your indoor air handler. It usually exits near the outdoor unit or into a floor drain.

visibility3. Visual Guidance

See what's happening and how to try the first recovery step.

1
Clear the drain line with a wet/dry vacuum
Clear the drain line with a wet/dry vacuumSeal the vacuum hose to the drain line end. Run the vacuum for 2-3 minutes to suction out the clog.
2
Flush the line with distilled vinegar
Flush the line with distilled vinegarPour 1 cup of distilled vinegar into the drain line access port. Let it sit for 30 minutes, then flush with water.
3
Check the drain pan for standing water
Check the drain pan for standing waterLook under the air handler for the drain pan. If water is present, the clog is cleared and the pan will drain.
4
Restart the AC and monitor
Restart the AC and monitorTurn the AC back on. Watch the drain line for steady water flow outside. Check for leaks over the next hour.

autorenew4. If That Doesn't Work

Try the next recovery options.

Turn off the AC and let the coil thawIf the coil is frozen, turn off the system for a few hours. Ice melting can clear minor clogs and stop the leak temporarily.
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Pour vinegar down the condensate lineMix 50/50 vinegar and water and pour it into the condensate drain opening to kill algae growth.
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Frequently Asked Questions

How often should I clean my AC condensate line?expand_more
At least once a year before the cooling season. Monthly vinegar flushes during heavy use can prevent clogs.
Can I use bleach instead of vinegar?expand_more
Bleach is harsh on PVC and can damage your system. Distilled vinegar is safer and equally effective for algae.
Is a clogged condensate line covered under warranty?expand_more
Clogged lines from neglect are typically not covered. Annual maintenance is the homeowner's responsibility.

warning5. Stop DIY If

Don't continue if any of these apply.

reportThe drain pan is rusted through or cracked
reportWater is leaking from the ceiling or walls
reportThe drain line is frozen or has ice inside
Still stuck?Get personalized help with AI Recovery.

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This page provides general DIY guidance.
If you're unsure, it's always best to consult a professional.