Is your AC leaking water? Here are some common causes and risks of AC leaks, along with what we can do to help. Contact us for fast, local repair!
Seeing water around your air conditioner can be alarming — and for good reason. While your AC system naturally produces some moisture as it cools your home, leaks are never normal and usually signal a problem that needs attention.
At Thomas Hoffmann Air Conditioning & Heating, we frequently receive calls from St. Louis homeowners inquiring, “Why is my AC leaking water?” Let’s break down the most common causes and what you can do next to prevent further damage to your home or system.
The service tech Giovanni did a fantastic job. Our gas fireplace is working like new again so we’re ready for the cold weather!
Response from the owner:Thank you, Mr, for your fantastic review! We're glad to hear Giovanni provided you with excellent service and professionalism. Your recommendation means a lot to us!
⭐️⭐️⭐️⭐️⭐️ If I could give 10 stars, I absolutely would.
Last night our furnace went out unexpectedly, and with three kids in the house, the temperature dropped fast. Giovanni went above and beyond in every way possible. Instead of charging me a late-night service fee, he simply asked, “Are you decently handy?” and offered to walk me through some troubleshooting steps to get our heat back on so my children wouldn’t have to sleep in the cold.
Not only did he guide me through the process, he even FaceTimed me and showed me exactly what to take apart, how to put it back together, and what signals to watch for. It felt like having a real technician standing right next to me the entire time. Thanks to him, our heat was restored within minutes.
In a world where true customer service is hard to come by, Giovanni is a rare find. It is a guaranteed fact that any future repairs, maintenance, and the new heater/AC system we’ll be needing this coming summer/fall will absolutely be done through him. His honesty, kindness, and expertise have earned our business for life.
Highly, highly recommend.
Response from the owner:Thank you, Jeff, for sharing your experience! We're so glad to hear Giovanni was able to help you and your family during that tough situation. Your recommendation means a lot to us, and we appreciate your trust in our services for the future!
My neighbor referred these guys to me when had water heater problem. Previous company told me I needed to replace it. Tom’s technician fixed it for less than $200. This was over 2 years ago and have been using their service ever since. They are very trustworthy.
Response from the owner:Thank you, Mary, for sharing your experience and for trusting us with your water heater issue; we're glad our technician could help and that you've continued to rely on our services!
I called this company earlier today because I was having a bunch of issues with my HVAC system. They were incredibly friendly and walked me through troubleshooting step by step over the phone. They didn’t even charge me for the call. Thanks to their honest advice, I was able to get things running smoothly again. Really grateful for their help and would definitely recommend them if you want straightforward and trustworthy service. Five stars all the way!
Response from the owner:Thank you so much for the glowing review, Hector! We appreciate your business and look forward to working with you in the future.
Nick did not set current time. — Monday Hoffmans Zach came to fix correct time. We DID NOT want a timed thermostat — we prefer to set temperatures manually
Response from the owner:Thank you, Pat, for your kind words about Giovanni; we appreciate your feedback and are glad to hear that he made a positive impression.
Clear communication about arrival, service and costs.
Response from the owner:Thank you, Margaret, for your kind words! We appreciate your feedback on our clear communication and are glad you had a positive experience.
Response from the owner:Thank you, Hank, for your wonderful feedback; we're glad you enjoyed the fast, friendly, and professional service, and we'll be sure to keep up the great work!
I will highly recommend this business for your air and heater repair. Prompt, knowledgeable and courteous service.
Response from the owner:Thank you, Judy, for your kind words and recommendation! We're glad to hear you were pleased with our prompt and courteous service.
Thomas Hoffman was very responsive to our after hours inquiry, even walked us through some trouble shooting over the phone. We provided pictures of the unit and they were able to quickly buy, schedule and install the part to keep our family warm!
Response from the owner:Thank you, Ali! We're glad to hear that Thomas was responsive and helpful in getting everything sorted out for you and your family. Your feedback means a lot to us!
Nick came by, identified the problem quickly and had it fixed. Great service!
Response from the owner:Thank you, Ted! We're glad to hear that Nick provided you with quick and effective service. Your feedback is greatly appreciated!
Great service. Responsive. Well trained technicians. Honest friendly and thorough. I highly recommend Tom Hoffmann and his team.
Response from the owner:Thank you for your kind words! We appreciate your recommendation and are delighted to hear about your positive experience with our team.
Ryan Taylor with Thomas Hoffman did an outstanding job in servicing our unit & explaining everything to me, especially how our humidifier worked, since we were new home owners & had not had one before. Thank you!
Response from the owner:Thank you! We're glad to hear that Ryan and Thomas provided you with excellent service and helped you understand your new humidifier. We appreciate your feedback!
As always, the Hoffmann technician Zach was polite, professional, and efficient. Pricing is reasonable and even more importantly, they are dependable. I will continue to use Thomas Hoffman A/C and Heating.
Response from the owner:Thank you, Mark, for your kind words about our technician and for your continued trust in Thomas Hoffman A/C and Heating; we truly appreciate your support!
Response from the owner:Thank you, Brandon! We appreciate your kind words and are glad to hear about your positive experience with Hoffmann’s professionalism and thoroughness.
Our service technician arrived right on time and was professional, friendly, efficient and courteous. We couldn’t ask for more.
Response from the owner:Thank you for sharing your positive experience with our service technician! We appreciate your kind words and are glad to hear that you were satisfied with the service provided.
I'm a new customer and had my first appointment for furnace check.My tech was Zack and what a professional. He explained how he checked system and answered all my questions. This was a very good experience
Response from the owner:Thank you, Patricia, for your kind words! We're glad to hear that Zack provided you with a professional and informative experience during your furnace check. Your satisfaction means a lot to us!
Thomas Hoffman is a wonderful company to work with. Techs are knowledgeable, personable & efficient.
Response from the owner:Thank you, Christine, for your kind words about our team; we appreciate your feedback and are glad to hear you had a positive experience!
I called on December 25th at midnight and started leaving a message and Thomas Hoffman the owner called me back almost immediately. He said he would come out the next morning between 8:00 and 10:00 am snd he was promptly on time. He fixed my problem and while he was there I decided to get an estimate for a new furnace and air conditioning unit. The price was very reasonable and the installers one of them being his son were both very professional very courteous, polite, arrived on time and finished the same day. I enjoy knowing that I now have the support of Thomas Hoffman heating and air conditioning along with the peace of mind that comes with owning a Trane. Nothing stops a Trane.
Albert Koesterer
Response from the owner:Albert thanks so much for your kind reviews and your business. We truly appreciate it!!!
The Thomas Hoffmann team did a great job taking care of our semi annual HVAC maintenance. They not only worked with us to schedule the visit, but also did an excellent job sending us reminders on when they would be out.
Response from the owner:Thank you so much for the great review, Bob! We appreciate your support and are happy to hear you had a great experience!
Nick was excellent. Super profession, quick, and up front with the pricing (which was fair). Hopefully we don't need to call anyone to fix our AC again, but if we do - I'm calling Nick!
Response from the owner:Thank you, Layton, for your amazing review! We really appreciate your support and hope to be your first call for any future repairs!
Same day service. Technician arrived as scheduled. Replaced capacitor quickly. Friendly technician. Repair cost $429 seemed high for inexpensive part and 20 minutes labor.
Response from the owner:Thank you, Tom, for your feedback! We're glad to hear the technician was prompt and friendly, though we understand your concerns about the repair cost. We appreciate your insights and hope to serve you again in the future.
Response from the owner:Thank you so much, Al, for your excellent review; we truly appreciate your support and are glad to hear you had a great experience!
Thomas Hoffmann is the most professional and courteous of all the HVAC companies in St. Louis. It has kept my HVAC systems in good working order through the hottest and coldest days for many years.
Response from the owner:Thank you, Jonathan, for your kind words about our professionalism and courtesy; we truly appreciate your support!
I notified two companies at the same time regarding a malfunctioning AC unit and Wow! Super fast response from Hoffmann on a weekend no less, to fix our AC unit. Hoffmann’s tech responded to my call immediately and fixed our AC before Galmiche has even responded. Used to be a Galmiche customer, but will use Thomas Hoffmann from here on out!
Response from the owner:Thank you, Darlene, for your fantastic feedback! We're glad to hear that our team was able to respond quickly and resolve your AC issue. We appreciate your trust in us moving forward!
Ryan did a great job with my AC reinstall. Very knowledgeable company with Tom Hoffmann providing the engineering expertise.
Response from the owner:Thank you, Steve! We're glad to hear that Ryan did a great job on your AC reinstall, and we appreciate the shoutout to Tom's expertise. Your satisfaction means a lot to us!
These guy's are amazing same day service very well priced for the knowledge they have ask before doing anything to confirm they're my new go to
Response from the owner:Thank you, Cory! We're glad you found our service amazing and appreciate your kind words about our pricing and knowledge. We're here for you anytime!
🌬️ First, Is It Normal for an AC to Produce Water?
Yes — but only inside the system, not on your floor.
As your air conditioner pulls humidity from the air, moisture condenses on the evaporator coil and drips into a drain pan, then flows out of your home through a condensate drain line. If any part of this process is disrupted, water may leak or overflow, potentially causing water damage, mold, or system failure.
🔍 Six Common Reasons Your AC May Be Leaking Water
1. Clogged Condensate Drain Line
Over time, dust, algae, and mold can accumulate inside the drain line, preventing water from draining correctly. This causes the drain pan to fill and overflow.
📍 This is one of the most common AC issues during humid St. Louis summers.
2. Dirty or Blocked Air Filter
A clogged air filter restricts airflow, which can cause the evaporator coil to get too cold and freeze over. When it melts, excess water can overwhelm the drain pan and leak out.
💡 Regular filter changes help prevent this and improve system efficiency.
3. Low Refrigerant Levels
Low refrigerant can also lead to frozen coils. This typically results in both poor cooling performance and unexpected water leakage once the coil thaws.
🚨 Low refrigerant often signals a leak and should always be handled by a licensed HVAC technician.
4. Cracked or Rusted Drain Pans
Older systems (especially those over 10 years old) may have a corroded or cracked drain pan that can’t correctly hold water, leading to leaks.
🔧 This is usually an easy fix, but it does require inspection and replacement of the part.
5. Improper Installation or Uneven Unit Positioning
If your AC unit wasn’t installed level, water may pool in the wrong areas or fail to drain altogether. Even a slight tilt can lead to a persistent leak.
📏 This is especially important in new construction or after recent AC installations.
6. Excess Humidity or Oversized Unit
In some cases, high humidity or an oversized unit that short-cycles can create more condensation than your system is designed to handle, resulting in overflows or leaks.
🌡️ This is one reason why system sizing and home humidity control are so important.
🛑 Why You Shouldn’t Ignore a Leaking AC
Even a small water leak can quickly lead to:
Water damage to floors, ceilings, or drywall
Mold and mildew growth in ductwork or walls
Reduced system efficiency
Compressor or electrical damage from excess moisture
The earlier you address a leak, the more likely you are to avoid costly repairs or replacements.
✅ What You Can Do Next
If you notice your AC leaking water, don’t panic — but don’t ignore it either.
📞 Call a trusted HVAC professional to diagnose the issue and perform any needed repairs. At Thomas Hoffmann Air Conditioning & Heating, our expert technicians provide fast, honest, and thorough service to homes across St. Louis.
We’ll:
Inspect your drain line, coil, and refrigerant levels
Clean or repair any clogged or damaged components
Ensure your system is running safely and efficiently
🧰 Prevent Future AC Leaks With Regular Maintenance
The best way to avoid mid-summer breakdowns or water damage? Schedule a seasonal AC tune-up. Routine maintenance helps catch small problems — such as clogs, corrosion, or low refrigerant levels — before they cause serious issues.
🗓️ We recommend booking a spring or early summer inspection to keep your system leak-free and ready for the St. Louis heat.
💬 Need AC Leak Repair in St. Louis? We’re Here to Help.
Thomas Hoffmann Air Conditioning & Heating has proudly served St. Louis homeowners for over 30 years. We’re locally owned — not a national brand in disguise — and we treat every home like it’s our own.
