Quick answer: An AC leaking water inside is most often caused by a clogged condensate drain line, a dirty air filter, or a damaged drain pan. Shut the system off, clean up the water, and check the drain line first — most indoor AC leaks are fixable before they cause real water damage.

If you live in Snellville or nearby Loganville, Grayson, or Lawrenceville, your air conditioner works overtime pulling moisture out of Georgia's humid summer air. All that moisture has to go somewhere, and when the drainage system that carries it outside gets blocked or breaks down, the water backs up into your home instead. A small puddle around your indoor unit today can turn into stained ceilings, warped flooring, or mold growth in a matter of days — so it pays to find the cause quickly.

How Does Your AC Produce Water in the First Place?

Your air conditioner does two jobs at once: it cools your air and it dehumidifies it. As warm, humid air passes over the evaporator coil — the cold coil inside your indoor unit — moisture condenses on the coil the same way water beads on a glass of sweet tea in July. That condensation drips into a drain pan beneath the coil, then flows through a small PVC pipe called the condensate drain line, which carries it outside or to a drain.

On a humid Georgia afternoon, a central air system can pull five to twenty gallons of water out of your home's air in a single day. When everything is working, you never see a drop of it. When any link in that drainage chain fails — the pan, the line, or the pump — that water shows up on your floor.

6 Common Causes of an AC Leaking Water Inside

1. Clogged Condensate Drain Line

This is the number one culprit. Over time, algae, mold, dust, and debris build up inside the drain line — Georgia's humidity makes algae growth especially fast. Once the line clogs, water backs up into the drain pan, overflows, and drips into your home.

Fix: Find the drain line access point (usually a T-shaped vent with a cap, near the indoor unit) and the outdoor termination point. You can often clear a clog with a wet/dry vacuum sealed against the outdoor end of the line for a minute or two. Pouring a cup of distilled white vinegar into the access vent every few months helps keep algae from coming back.

2. Dirty Air Filter

A clogged filter restricts airflow over the evaporator coil. With too little warm air passing over it, the coil can get too cold and ice over. When the ice melts, it produces more water than the drain pan is designed to handle, and the overflow ends up on your floor.

Fix: Check your filter. If you can't see light through it, replace it. During heavy-use summer months in Snellville, most homes need a new filter every 30 to 60 days, especially with pets or spring pollen still circulating in the ductwork.

3. Cracked or Rusted Drain Pan

The drain pan sits under the evaporator coil and catches every drop of condensation. On systems more than 10 to 15 years old, pans commonly rust through or crack, letting water slip past before it ever reaches the drain line.

Fix: Inspect the pan with a flashlight while the system runs. If you see water dripping through the pan itself, the pan needs to be replaced — a job for a licensed technician, since it usually requires partial disassembly around the coil.

4. Frozen Evaporator Coil

Low refrigerant, blocked airflow, or a failing blower motor can all cause the evaporator coil to freeze into a block of ice. Once the system shuts off, the ice melts quickly — and the sudden rush of meltwater overwhelms the drain pan.

Fix: Turn the cooling off and set the fan to ON to thaw the coil, then check the filter. If the coil freezes again after a filter change, you likely have a refrigerant leak or airflow problem that needs professional AC repair. Refrigerant handling requires EPA certification, so this is never a DIY fix.

5. Broken Condensate Pump

If your indoor unit sits in a basement or anywhere below the drain's exit point, a small condensate pump pushes the water up and out. When the pump's float switch or motor fails, water collects until it spills over.

Fix: Listen for the pump cycling on as its reservoir fills. If the reservoir is full and the pump stays silent, it has likely failed and needs repair or replacement.

6. Improper Installation or a Disconnected Drain Line

If the leak started soon after a new system was installed, the drain line may not have enough downward slope, or a fitting may have worked loose. Even a slightly unlevel indoor unit can send water over the edge of the pan instead of into the drain.

Fix: A technician can re-slope the line, reseal fittings, and level the unit. This is usually a quick correction once it's diagnosed.

What Should You Do Right Now?

1. Turn the system off. This stops new condensation from forming and prevents water from reaching electrical components or more of your flooring.

2. Clean up the water quickly. Towel up standing water and run a fan across damp carpet or drywall. In Georgia's humidity, mold can begin growing on wet materials within 24 to 48 hours.

3. Check the air filter. If it's dirty, replace it before restarting the system.

4. Look at the drain pan and line. A full pan points to a clogged line; a dry pan with water nearby suggests a crack or a duct sweating issue.

5. Restart and watch. If water returns within a few hours, leave the system off and schedule service — continuing to run a leaking unit risks damage to the unit and your home.

How to Prevent AC Water Leaks in Snellville's Climate

Gwinnett County summers are long, humid, and hard on cooling systems. A few habits go a long way:

• Flush the drain line with vinegar every one to two months. A cup of distilled white vinegar in the access vent keeps algae from taking hold during the peak cooling season.
• Change filters on schedule. Every 30 to 60 days in summer. Set a phone reminder — it's the cheapest insurance your system has.
• Keep the area around the indoor unit clear. Good airflow and easy visibility help you spot moisture early, before it soaks anything.
• Consider a float switch. This inexpensive device shuts the system down automatically if the drain pan overfills — a smart safeguard for units in attics or above finished ceilings.
• Schedule spring maintenance. A professional AC maintenance visit includes clearing the condensate line, inspecting the pan, and checking refrigerant charge — catching leak causes before July heat arrives.

When to Call a Professional

Some leaks are a five-minute fix, but call a licensed technician if any of these apply:

• The leak returns after you've cleared the drain line and replaced the filter
• The evaporator coil keeps freezing — a likely refrigerant leak
• The drain pan is rusted through or cracked
• Water has reached drywall, ceilings, or electrical components
• The condensate pump has failed
• Your system is over 10 years old and leaking for the first time

Henson Heating, Air and Plumbing has been helping homeowners across Snellville, Loganville, Grayson, Monroe, and Lawrenceville stop AC leaks before they become water damage claims. Our licensed technicians arrive with the parts to fix most condensate problems in a single visit, and every repair is backed by our workmanship guarantee. If your AC is leaking water inside your Snellville home, call us at (678) 475-7622 or schedule service online today.