AC Leaking Water Inside the House? Here's the Real Cause

An AC leaking water inside the house is almost always caused by a clogged condensate drain line, not low refrigerant. Your evaporator coil pulls gallons of moisture out of the air daily. When the drain line clogs with algae, water backs up into the pan and overflows onto the floor.

Before you panic, confirm what you are actually looking at. Refrigerant is a gas at room temperature, not a puddle on the floor. If you see a clear, odorless puddle under your air handler or furnace cabinet, it is condensate water. If you hear a hissing sound, see ice on the copper refrigerant lines, or the unit is running but not cooling, that is a different problem and you should shut the system off and call a technician. This post is about the water leak only.

In our service trucks across Pekin and Peoria, these five causes account for almost every indoor AC water leak we run:

• Clogged condensate drain line (about 80% of calls). Algae and slime grow inside the warm, wet PVC line and block the flow. The pan overflows and water finds the floor.
• Cracked or rusted drain pan. On older systems (10+ years), the metal pan under the coil corrodes and develops pinhole leaks. Replacement is the only real fix.
• Broken condensate pump. Basement installs use a small pump to lift water up to a drain. When the float switch fails or the motor burns out, the reservoir overflows.
• Frozen evaporator coil thawing out. A dirty filter or low refrigerant freezes the coil. When you shut the system off, the ice melts all at once and overwhelms the drain pan. Fix the freeze cause, not just the water.
• Disconnected or improperly sloped drain line. A PVC joint pops loose or the line sags, and water pools instead of draining. Common after basement remodels.

The EPA notes that any indoor water leak left more than 24 to 48 hours can start mold growth. An AC leak is not just an HVAC problem, it is a moisture problem.

Three steps are safe for any homeowner and stop the damage while you wait for service:

1. Turn the AC off at the thermostat. Set it to Off, not just up a few degrees. This stops new water from being produced.
2. Soak up standing water. Towels, a wet/dry shop vac, anything. Standing water under an air handler will warp subfloor and stain drywall within a day.
3. Find the condensate drain access. Look for a small white PVC pipe with a cap or T-fitting near the indoor unit. If you have a wet/dry vac, you can suction the outdoor end of the drain line to pull the clog out. This works on about half of clogs and buys you time.

What not to do: do not pour bleach down the line if you have not done it before, do not open the air handler cabinet, and do not run the AC again until the drain is cleared. Restarting just refills the pan and floods the floor again.

It is both, which is why this call frustrates homeowners. A pure HVAC company will clear the drain and leave. A pure plumber will not touch the air handler. The repair often needs a technician who handles both systems together, especially when the leak has reached drywall, subfloor, or a finished basement.

If the water is also pooling near a floor drain or you are not sure where the water is coming from, the condensate drain may be tied into a clogged household drain line. That is a plumbing fix, not an HVAC fix. We diagnose both at the same visit so you are not paying two trip charges.

Most indoor AC water leak repairs in Central Illinois fall between $150 and $700:

• Drain line clear and flush: $150 to $300
• New condensate pump installed: $250 to $500
• Drain pan replacement: $400 to $700 depending on coil access
• Float switch or safety switch install: $150 to $275 (prevents future floods, worth every dollar)
• Mold remediation or drywall repair: separate trade, often $500 to $3,000 if the leak ran for days

A flat upfront price before any work begins is the standard you should expect. If the technician finds the leak is actually from a frozen coil or failing compressor, the conversation shifts to full AC repair pricing or replacement. We will tell you straight, no upsell.

At Trouble Free Heating, Cooling & Plumbing, we are licensed for both the HVAC and the plumbing side of this repair, so one technician and one trip charge solves it. We clear the drain line, test the pump and float switch, inspect the pan for corrosion, and check that the system is not freezing up and masking the real cause. You get a flat price in writing before any work starts.

We service indoor AC leaks across Pekin, Peoria, Morton, Washington, East Peoria, Canton, and surrounding Central Illinois communities. A real person answers our phone 24/7.

To stop the water and protect your home, call (309) 347-5309 or schedule AC service today.

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