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.
Love that it’s the same technician every time. Let’s me know what he found and any concerns he might have regarding our units. Great customer service.
Response from the owner:Thank you, Theresa! We're glad to hear you appreciate having the same technician and the communication about your units. Your feedback on our customer service means a lot to us!
From the phone to the completion of the job everyone is so polite and informative. I had Giovani as our representative and he was very informative and professional, and knew exactly what the problem was. Thanks so much.
Response from the owner:Thank you for the kind review, Frank! We appreciate you and your business.
Zach did an excellent job! Always courteous and friendly. We would highly recommend calling Thomas Hoffmann HVAC for any heating and cooling needs.
Response from the owner:Thank you, Allan! We're glad to hear that Zach provided excellent service and appreciate your recommendation for Thomas Hoffmann HVAC.
Was able to locate the problem right away and replace a switch and add Freon very nice job by this employee. I will recommend Thomas Hoffman for future references.
Response from the owner:Thank you, William! We're glad to hear that our team was able to quickly address the issue and that you had a positive experience with Thomas. Your recommendation means a lot to us!
I had Nick come out. He was awesome. Very knowledgeable, prompt and helpful. I will definitely recommend Thomas Hoffmann HVAC to others in need of HVAC support.
Response from the owner:Thank you, Jack! We're glad to hear that Nick provided you with excellent service. We appreciate your recommendation and look forward to assisting you and others in the future.
From our initial quote until the new furnace and AC were completed, everything was smooth and efficient. Zachary and Giovanni were excellent on-site, taking time to explain the installation as well as leaving the home clean. Thank you Thomas Hoffmann team
Response from the owner:Thank you! We're glad to hear that the installation process was smooth and efficient. Zachary and Giovanni will be pleased to know their efforts made a positive impact. We appreciate your kind words about the team!
Update 4/6/26: Zach Sperling is such a pleasant and knowledgeable technician that I recommend him highly. Thomas Heating has been a wonderful company to work with in my maintenance plan. If you are looking for a reputable company, look no more.
This company is so responsive that I love them. They respond immediately, and I trust them to tell me what needs to be done. I haven’t been steered wrong yet. They are genuinely nice to work with and honest. I use their maintenance program which I highly recommend.
Response from the owner:Thank you for your kind words, we truly appreciate your trust in us and are glad to hear about your positive experience with our services.
work good but got at least 6 messages from them very annoying
Response from the owner:Thank you for your feedback, Harold. We appreciate your input and understand how too many messages can be frustrating. We'll work on improving that experience for you.
Nick was great! He came right out and was able to solve the problem fairly easily. He communicated well and helped us prevent a future problem as well.
Response from the owner:Thank you for the review, Philip! We are happy to hear you had a pleasant experience working with us.
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.
They have never failed to fix my hvac problems. These folks are top tier.
Response from the owner:Thank you for the wonderful feedback, Greg! We're glad to hear that you've had such positive experiences with our team. Providing timely and effective service is our priority, and we're here whenever you need us. Looking forward to assisting you again!
Giovanni was very professional, helpful, patient and helped me figure out the issue, if it was covered under warranty, and next steps. Great overall experience and much appreciated.
Response from the owner:Thank you, Amy! We're glad to hear that Giovanni provided you with such professional and helpful service. Your appreciation means a lot to us!
Always professional and thorough whenever they service our home. We have used Thomas Hoffmann Air Conditioning & Heating multiple times since we moved into our home and will continue to use them in the future.
Response from the owner:Thank you for the thoughtful review, Joe. We appreciate you and your business!
0 stars if I could. Bought a faulty (not to mention overpriced) surface igniter, called back five minutes later after installing, of course they didn’t stand behind their part. Go to Grainger instead. Same (working) part, half the price.
Response from the owner:Hi there. I am unable to locate your customer profile. Please give our office a call at 314-471-7625 so we can get this figured out for you.
My furnace was not working. A very nice gentleman came out this morning and fixed the problem and now I have much needed heat. He was very professional and courteous. I will definitely be using them again when the need arises.
Response from the owner:Thank you for the positive feedback! We're glad to hear that you were pleased with our prompt and friendly service. We look forward to assisting you again in the future!
I will always call Hoffmans for my air and heat needs. They were out to my daughters house that day and fixed it. It was right before the weekend storm with below zero temps the next day. They saved my daughter and grandbabies. I could never thank them more.
Response from the owner:We are so happy to hear that we could help! Thank you for the kind review.
Snow and drifting snow covered intake and out take vents causing the furnace emergency to shut off furnace. Cleaned off the driftibg/ snow off roof and vents furnace works perfect now. Thank you and great job Nick.
Response from the owner:Thanks for the great review, Scott! We appreciate your support.
5 stars! Nick was here to fix my heater within 2 hours of my call. He explained the problem to me thoroughly and got the job done quickly & professionally. Thank you so much!
Response from the owner:Thank you for the kind review, Jennifer! Glad we could help.
Extremely thorough and educational. They do a wonderful job of explaining everything and making sure I was comfortable knowing how the systems worked in my house!
Response from the owner:Thanks for the great review, Matthew! We appreciate your support.
I noticed a strange noise that I was concerned was linked to my furnace. I called Thomas Hoffman Heating & Cooling and Nick came right out. He was very thorough checking all components. Thankfully all checked out for us this visit. Definitely recommend Thomas Hoffman Heating & Cooling!
Response from the owner:Thank you so much for the kind review, Abby! We appreciate your business and look forward to servicing you in the future.
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!
Got a quote over the phone. Everything was explained thoroughly. Dakota, my technician arrived and on time, was very professional and knowledgeable. He didn’t try to upsell or change anything. He did a great job. We can already tell the difference since the ducts and vents were cleaned. Would recommend an use Hoffman again in the future.
Response from the owner:Happy to hear you had a pleasant experience using Thomas Hoffmann!
The technician, Ryan, was knowledgeable and helpful in identifying the issue with our mini split AC unit. They are the second company we called after issues with the first and will be using Hoffmann again.
Response from the owner:We are so happy to hear your experience with Thomas Hoffmann was pleasant. Thank you for your kind review, & we look forward to working with you in the future!
🌬️ 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.
