San Antonio · AC Drain Line Repair · Family-Owned Since 1996
If you have water dripping from a ceiling vent, a soggy spot under your air handler, or your AC just shut itself off, your condensate drain is clogged. Cleaning takes 30 minutes, costs $149–$249, and prevents thousands in water damage.
Typical price
$149–$249
Time to fix
30–45 minutes
Urgency
Critical — water damage risk
Your AC pulls humidity out of the air, and that humidity has to go somewhere. It drips off the evaporator coil into a drain pan, then runs through a small PVC pipe (the condensate drain line) to the outside of your house — usually a copper or PVC stub by your hose bib.
In San Antonio's humidity, this line collects algae, mold, and biofilm. When it clogs, water backs up. If you have a float switch (most newer systems do), the AC shuts itself off as a safety. If you don't, water overflows the drain pan, soaks the ceiling sheetrock under your attic unit, and you've got a $5,000-$15,000 ceiling repair on your hands.
We've literally never met a San Antonio AC system that didn't have at least some algae buildup in the drain. Most homes need it cleared once a year. Maintenance plan customers get this done automatically every spring — that's actually the #1 problem the plan prevents.
What it costs in San Antonio
$149–$249 — Includes full vacuum-out, flush, algae tablet, and verifying the float switch works. Higher end if the line has to be re-routed or re-glued. Our $59 diagnostic is waived when you approve the repair, so you only pay for the fix itself.
If two or more of these sound familiar, it's probably your ac drain line.
Here's exactly what a Carnes and Sons tech does at your house — no mystery, no upselling.
Every drain line has (or should have) a cleanout tee near the air handler and a termination outside. We find both. If the original installer skipped the cleanout, we add one while we're there.
We seal a wet/dry shop vac to the exterior termination and pull a strong vacuum for 2-3 minutes. This is the most effective way to clear a clog — pushing water from the top often just packs the clog harder.
Once the line is open, we pour a flush of warm water mixed with a mild biocide through the cleanout to wash out residue. We do NOT use bleach (bleach degrades PVC primer joints over time and kills any landscaping the drain dumps near).
We deliberately raise the float to confirm it cuts power to the AC. If it doesn't, we replace it — usually $50-80 added. A non-working float is what causes the catastrophic ceiling damage we see every summer.
We add a time-release algaecide tablet to the drain pan that prevents new growth for 4-6 months. Then we re-seal the cleanout cap.
Get Your AC Drain Line Diagnosed Today
Tell us what's happening. We'll text you back in minutes — no call center, no robo-calls.
$149 to $249 for a standard clearing — includes vacuum-out, flush, algae tablet, and float switch test. If the line has to be re-routed because of bad slope or has to be cut and re-glued, it can go higher, but we always quote that before doing the extra work.
Once a year minimum in San Antonio's climate. Every 6 months if you have pets that shed heavily or if you've had clogs before. Maintenance plan customers get this done automatically in spring.
Sometimes. If you have a shop vac and can find the outside drain termination, attaching the vac and pulling vacuum for 2-3 minutes will clear a fresh clog about half the time. If that doesn't work, or if you can't find the outside stub, or if water is already on the floor or ceiling, call us — we'd rather charge $149 than see you have a $5,000 ceiling repair.
No, despite what you'll see online. Bleach eats away at the PVC primer joints over years of use and causes leaks at the glued fittings — we've replaced too many drain lines failed by bleach. Use a mild algaecide tablet or 50/50 distilled white vinegar instead. Even better: just keep up with annual cleaning.
Probably yes. The float switch on the drain pan cuts 24V power to the thermostat when it senses water backing up — it's a safety to force you to address the problem before water damages your ceiling. Once we clear the drain and reset the float, the stat lights back up.
A small safety device in the drain pan that detects when water is backing up and shuts off the AC to prevent overflow. Required by code on attic installs since the early 2000s. If you have an older attic unit and have never had one installed, we strongly recommend adding one — $80-120 and it prevents the worst-case ceiling collapse scenarios.
Three usual suspects: (1) the drain slope is too flat — water sits and grows algae faster, (2) the indoor coil is dirty and dumping a lot of debris into the pan, or (3) no algae tablets are being used between cleanings. We can fix the slope and clean the coil; you can add tablets.
Most home warranties classify drain cleaning as maintenance, not a covered repair — so usually no. The water damage from a failed drain is also typically excluded. Worth a few hundred dollars a year of prevention.
We're based in Stone Oak and roll trucks across San Antonio and the surrounding Hill Country every day.
License TACLB29435E · Family-Owned Since 1996
Cities & neighborhoods we serve
San Antonio · Stone Oak · Alamo Heights · Hollywood Park · Hill Country Village · Shavano Park · Castle Hills · Leon Valley · Helotes · Boerne · Fair Oaks Ranch · Bulverde · Timberwood Park · Garden Ridge · Schertz · Cibolo · Selma · Universal City · Live Oak · Converse · Windcrest · New Braunfels
No call center. The owner or one of his sons picks up.
(210) 600-5091