AC Leaking Water in Tempe & the East Valley — Where It's Coming From and What the Fix Costs
Water at the air handler, a wet ceiling, or a drip from the roof unit. Clogged drain lines cause most of it. Here's how to find the source, what to shut off, and what each fix runs.
Your AC makes water on purpose. Every hour it runs in a Valley summer, the indoor coil pulls moisture out of the air and sends it down a drain line. A leak means that water isn't making it out. Nine times out of ten the fix is cheap. The tenth time is a ceiling repair, which is why you don't wait.
First: shut it off if water is on a ceiling
Turn the thermostat to Off. Not Auto, not Fan. A ceiling stain under an attic air handler means water is already sitting on drywall, and drywall gives way without much warning. Put a bucket under it and call.
Where the water is coming from
- Puddle at the indoor unit (closet or garage): clogged primary drain line, cracked drain pan, or a condensate pump that quit.
- Stain on the ceiling under an attic unit: primary drain clogged and the secondary pan or float switch didn't catch it. Common in South Tempe, Chandler and Gilbert homes with attic air handlers.
- Water dripping from a rooftop package unit or down the wall: clogged drain off the unit, or a curb or duct seal leaking. On Mesa and Tempe package units, monsoon rain through a bad curb looks exactly like a condensate leak.
- Ice on the copper lines, then water when it melts: that's a frozen coil, not a drain problem. See AC freezing up.
- Water from the drain line outside, constantly: that's normal. A Phoenix system can move gallons a day during monsoon humidity.
The two things you can check yourself
- The filter. A clogged filter can freeze the coil, and a frozen coil floods the pan when it thaws. Change it. Which filter to buy.
- The float switch. Many systems have a small switch on the drain pan or line that shuts the AC off when water backs up. If your system quit and there's water in the pan, the switch did its job. Don't bypass it.
Skip the shop-vac on the outside drain unless you know where the line runs. Pulling the wrong way on a cracked pan or a glued fitting turns a $200 call into a $900 one.
What the fixes cost
Ranges for a standard residential system. Your written price comes before any work starts.
| Clear a clogged drain line (flush + treat) | $150–$300 | The most common fix |
| Float switch or secondary safety switch | $150–$350 | Should be on every attic system |
| Condensate pump | $200–$450 | Units in closets or basements with no gravity drain |
| Drain pan (secondary, attic) | $250–$600 | Rusted-through metal pans on older systems |
| Evaporator coil or primary pan leak | $1,200–$2,500 | Repair-or-replace conversation past 12 years |
Why it happens more here
Monsoon season. July through September, indoor humidity jumps and the coil makes several times the water it does in June. Drain lines that have been building algae and dust since spring finally clog. A spring tune-up flushes and treats the line before the humid months. It's part of our $59.95 tune-up. More on monsoon humidity and your AC.
When it's a bigger problem
A drain pan that keeps rusting through, a coil that leaks water at the joints, or a system that floods every summer usually points to an undersized drain, a sagging line with no slope, or a system that's past its life. We'll show you which before we quote anything big. Repair or replace math.
Questions people ask
Is it normal for water to drip outside my house from the AC?+
Yes. A white or gray PVC pipe outside the house, near the condenser or out of the roof, is the condensate drain. Steady dripping in summer means it's working.
Can I keep running my AC if it's leaking water?+
Not if water is reaching a ceiling, floor or wall. Shut it off at the thermostat. If water is only in the drain pan and the system shut itself off, the float switch is working; call to clear the line.
How much does it cost to unclog an AC drain line?+
Usually $150 to $300 in the East Valley, including flushing and treating the line. It's often done on the first visit.
How do I stop my AC drain from clogging?+
Flush and treat the line every spring and keep the filter changed. Our tune-up includes clearing and treating the drain.