Why Is My AC Leaking Water? Causes and Fixes (Lubbock, TX)

Even in dry West Texas air, a central AC pulls gallons of water out of your home on a 100° Lubbock afternoon. When that water shows up on the floor or in the ceiling instead of draining outside, something in the drain path has failed — and the fix is often simpler than it looks.

Where is the water coming from?

The water dripping from your AC is condensate — moisture the evaporator coil pulls out of your home's air as it cools. That water collects in a drain pan under the indoor coil and flows out of the house through a small PVC condensate line. When the line clogs, the pan cracks, or the coil ices over, the water has nowhere to go but into your house.

In Lubbock, the most common culprit is a clogged drain line. The fine dust that gets past the filter mixes with moisture in the pan and feeds algae growth inside the line, and over a summer of heavy runtime the line slowly closes off.

What should I check first when my AC leaks water?

Start by shutting the system off, then work through these checks — they cover most leaks and cost nothing but a few minutes.

1. Turn the system off

Every hour the AC runs adds more water to a pan that's already overflowing. Switch the thermostat to OFF. If the system shut itself down and won't restart, a condensate float switch may have tripped — that's a safety device doing its job, and it usually means the pan or line is backed up. (A system that won't start for this reason is one of the items in our no-start troubleshooting checklist.)

2. Check the air filter

A clogged filter chokes airflow across the coil, which can make the coil freeze into a block of ice. When that ice melts, it sheds water faster than the pan and drain can handle. If the filter is gray and loaded with dust, replace it — in a Lubbock summer, filters clog much faster than the box suggests.

3. Look at the drain pan

With the power off, look under the indoor coil — in the closet, garage, or attic. Standing water in the primary pan points to a clog downstream. Water in a second, shallower pan under the whole unit means the primary pan overflowed — common with attic installations — and that secondary pan is the only thing between the leak and your ceiling.

4. Clear the condensate line

Find where the PVC drain line exits the house, usually near the outdoor unit. Seal a wet/dry vacuum against the end of the pipe for a minute or two — that pulls most clogs out. Then pour a cup of plain white vinegar into the drain access tee near the indoor unit to kill the algae the clog grew from. If water flows steadily outside once the system is running again, you've likely fixed it.

Which AC water leaks need a professional?

Some leaks point to problems a homeowner can't — and shouldn't — fix:

• A coil that keeps freezing. If ice returns after you've replaced the filter, the usual cause is a refrigerant leak. Refrigerant is federally regulated and requires certification to handle, so this is strictly a licensed-tech repair. Our post on why ACs freeze up covers the warning signs.
• A cracked or rusted drain pan. Metal pans on older systems rust through over time. On a unit nearing the end of its life, a corroded pan is often one of several failures arriving together, and it's worth weighing repair against replacement.
• A failed condensate pump. Installations that can't drain by gravity use a small pump instead. If it dies, water backs up fast — a quick swap for a tech.
• A line that clogs again within weeks. Repeat clogs suggest the line is sagging, poorly sloped, or blocked deeper than a shop vac can reach. A pro can flush it end to end as part of an AC service call.

Can a leaking AC damage my house?

Yes — often before you notice the leak. Condensate overflow soaks drywall, stains the ceilings below attic units, warps wood flooring, and can feed mold inside walls even in Lubbock's dry climate. That's why the first move is always to shut the system off — and why a tripped float switch should never be bypassed just to get the cold air back.

How do I keep the drain line from clogging again?

Condensate clogs are one of the most preventable AC problems in West Texas:

• Check the filter monthly in summer. Less dust past the filter means less sludge in the pan and line.
• Pour a cup of white vinegar into the drain access every month or two during cooling season to keep algae from growing back.
• Have the drain flushed at your annual tune-up. A proper spring tune-up includes clearing and testing the condensate drain before heavy summer runtime starts.

If you'd rather have someone check the whole drain setup — pan, line, slope, float switch — request a visit through our callback form and we'll connect you with a local Lubbock pro.

Frequently asked questions