HVAC systems leak, causing mold and water damage

“Trane heat pump, unit is approximately 8 years old. There’s plenty of condensation flowing and following the intended path as it should, but I’m getting some additional condensation dripping from the central area of the A coil. The filter gets wet and some standing water collects on the floor. I’ve read the most likely causes are low line pressure or air flow obstruction from dirt or bent fins. There are no bent fins. I doubt it’s low line pressure because the unit runs well and delivers ice col”

“There’s been a puddle forming and the liquid seems to be coming from a pipe from the house I first thought this was the sprinkler, but the HOA said it’s my AC. Before I have someone to come and look, is this an easy fix? Thank you for any suggestions. submitted by /u/kenji4861 [link] [comments]”

“So about a month ago, I discovered a leak in my ceiling and had a company come out to take a look at it. They initially told me that the pipe needed to be re-insulated and that it would stop leaking. So they rewrap it and call it good. But it was still leaking. I called them back and they came back out, say thing that the dampers in my ductwork system were in the wrong position, so they “fixed” that. They then said that there was nothing else they could do for my leak… but that should work. It d”

“I'm a new homeowner and this is my first summer in this house. Around mid summer I noticed that the AC condensation pipe was leaking water right where that white hexagon screw meets the furnace. The water was dripping down into the furnace vent. I can't get it tighter than it already was and I'm afraid of cracking something if I try harder. For now, we have paper towels absorbing the leak and we've been changing them out when they become too soggy. The PVC pipe isn't glued, w”

“A new wet spot appeared on the ceiling and I went in the attic to check and it's coming from the ac. The drain line going to the sink was clogged so I cleared it but... the tray underneath the coil is very wet and rusted so I'm thinking of drilling some holes for the water to drain into and bend some sheet metal into a tray underneath and hook that to the drain line going to the sink? Does that make sense? Or is there a bigger issue here? Also the pvc has a vent? When the AC is on it jus”

Blocked condensate line on furnace

“Had my HVAC inspected today by the company that installed it 2 years ago. They noted this leak which they think is new (I honestly haven’t looked so I don’t know how long it’s been going on). They think related to the chimney and possible hail damage on the top of the chimney. Does that seem like a plausible explanation or is this because of a bad install? submitted by /u/chem2617 [link] [comments]”

“New home owner and unfamiliar with this stuff. Been in the house for a year now and just a month ago this pipe just started leaking a lot when our AC runs. Confirmed it stops when AC is off. Why did it just started leaking now? Is too much a concern? Flower box seems to love it, but we don’t. I went up in the attic and didn’t notice anything out of the ordinary. TIA! submitted by /u/Lkollman [link] [comments]”

“My relatively new house had a leak by the AC unit today. My unit is installed in a hvac closet vertically with the blower on top of the coil. Can someone tell me if this is required to have a p-trap, because there isn’t one. The vent pipe goes about 40 feet under the house and comes out by the compressor unit. Today the pan was full of water but when I pulled the safety switch out it didn’t seem that high and the switch did not shut the unit off. I’m not sure what to make if it. The original ins”

“I’ve added some photos of what I found when I took the service panels off. Wife noticed some water on the floor by the corner of our furnace this morning. So I traced it, followed the rust path to the upper compartment behind what I’m assuming is a blower assembly.. I am a licensed plumber but I have never really messed with the guts in a furnace prior to this. I made sure the condensate drain isn’t clogged, from the point it comes out of unit down to the condensate pump is clear…. And confirmed”

submitted by /u/No_Muscle_3128 [link] [comments]

“First off this unit is 3 years old I had the house built, and I’m noticing a lot of white corrosive residue on ducts and I’m wondering if that’s normal? Second where the copper lines go into unit a lot of cold air is escaping and one line is sweating blue is this normal? I did have issues where the duct coming off ac was leaking outside the drain pan and they had to replace it and relevel it. submitted by /u/CodAddict2020 [link] [comments]”

“Sorry if this has been discussed before- we installed a brand new AC system this summer. I have a weatherproof cover for the condenser outside… is there anything else I should be doing to wrap it up for the winter? I know someone who throws the breaker for the winter. Is that necessary? Any advice would be greatly appreciated!! Trying to protect this pricey investment as best I can! TYIA!! submitted by /u/slizzard777 [link] [comments]”

“Leak coming from plastic housing unit in the black seam area right above ac drain line…. is this a new evaporator core job? submitted by /u/Ok_Soup_5047 [link] [comments]”

“Just had a new wall a/c installed in my upstairs bedroom today. It started leaking on the left side so I called the contractor to come back and take a look. He said it might be a leveling issue since it seemed a bit slanted, so he readjusted it. A few hours later, the right side is leaking now.. Also whenever I turn the a/c on, I hear a gurgling sound in the beginning. I wish I knew how to fix it myself instead of having him come again and still not fix the issue sigh. I’m also worried about wat”

“The drain in the front of my house is continuously draining. It's what I think is the hvac condensate but It seems like too much water to be just draining. It's coming out like a faucet half way on. Any thoughts? submitted by /u/Beneficial_Ad_490 [link] [comments]”

“i’m scared, do i need to call someone immediately? submitted by /u/Life-Point-4130 [link] [comments]”

“Need some advice because I’m kinda lost at this point. New construction house and I’ve already had the HVAC company out multiple times. It originally started leaking water into the drain pan. They said the TXV was bad, then later another tech said the TXV was installed wrong and the coil was damaged too. They replaced the coil and the TXV and the AC is cooling again, but I’m STILL seeing water dripping into the secondary drain pan under the unit. The system was off for like 2 days before they re”

“HVAC air handler, and the clear, odorless water is condensation leaking from a clogged AC drain line”

“Can anyone give me possible issues that could be causing the inducer motor for my furnace to be filling up with water /condensation from my ac? Could It be that the drain pan is cracked and is leaking water into the heat exchanger, or the heat exchanger tubes are possibly cracked. I checked the roof cap for the flue gas pipe and it seems good so I don’t think water is getting in through there. The furnace is a goodman gms80703AN model. submitted by /u/Lucky_Information873 [link] &#32”

submitted by /u/PlanMaison [link] [comments]

“So I have an A/C unit that's from the late 90s and I've lived in the same house with the same unit for 24 years now. About a week ago a piece of black kind of flexible plastic that was jagged was on the chair to my computer that sits right under a vent in my room. I had never seen anything like this piece and figured maybe it came out of the vent. My dad ended up taking down my vent to look in there and make sure nothing was sticking out of the ceiling vent. (My dad also threw the piece”

“We had replaced both our cooling and heating units a few months ago. I do not remember it looking so alarming when they were finished. Is this a "get it looked at ASAP" kind of issue? submitted by /u/Rosefier [link] [comments]”

“I can’t tell if the water is from inside the handler or from condensation because the handler leaks cold air where the tape is. submitted by /u/Someguy56731 [link] [comments]”

“Okay, so long story short. We installed a new HVAC system about a year or so ago. We did that because it was leaking Freon and it kept having issues with draining. At the time I had asked this company to look into the draining issues and they claimed it was fixed. Now a year and a half later, I walk into my bathroom and don’t feel air coming out of the vent. The technician says there’s like 10” of water in the duct and that it can accumulate over a relatively short period of time. He suggests ad”

“My apartment above my ac leaked into my roof and left water damage. I think there could be mold, but my apartment denies it the moisture meter was showing red and I was told it can’t be mold if it doesn’t rub off. They stripped my walls, so the main mold spots are visibly gone. The first two photos are of the walls before they took the paint off, next two are the walls after, then finally just the water damage itself. They are saying it’s just discoloration not mold. Should I hire an inspector,”

“The HVAC ducts in our attic are split and leaking in several places and mold is developing. The HVAC system and ducts were installed five years ago. The company that installed them wants $3,000 to fix the damaged ducts, claiming five years ago there were different standards for installing them and this led to the leaks and splitting. We live in Northeastern Florida, where it gets very hot. Our attic is insulated but that doesn't keep the temperature from skyrocketing up there in the warmer m”

“My upstairs unit is about two years old. I luckily noticed it was leaking from the left rear of unit and also dripping from below into the return space. I shop vac’d the drain line and left it off for two hours. It still was dripping from the same spots. Drain line was clear and float switch worked normally. Any ideas? submitted by /u/MarkCM84 [link] [comments]”

“Trying to fix my ac that is leaking water. I’m a single mom in survival mode and can’t hire help right now. You all have been so generous in helping me. So thank u! I’m trying to clear this main drain line. It probably hasn’t been flushed or cleared in 25 years. You cannot access it in the attic because they installed it backwards and I cannot get behind the unit to pour anything down it. It’s plumed down below to a sink we don’t use. The sink is draining fine as I’ve poured lots of vinegar and”

“This is my condensate line, it’s always full and I’m worried water has been dripping into the crack between my house and the concrete, should I re concrete this so there is no resivour. It just doesn’t look right. Thank you submitted by /u/Ancientgra1n [link] [comments]”

We had our old hvac replaced a little over a year ago. Had new duct work and also a pump added. Our system is located in the attic and woke up this…

“We just moved in a little bit ago. For the second time we got a leak caused by the condensation pan filling up. Our landlord cleared the condensation pan drain line last time and he’s sending out an HVAC company tomorrow to look at it. I’m posting here so I can try to be more informed talking to the company and also my landlord. There is a lot of duct tape on this thing and I specifically took a picture of the duct taped insulation which is collecting moisture. I’m an engineer but don’t know any”

“This sits on top of the humidifier portion of our hvac. The humidity is set to "off" because that's the last thing we need to add in the summer. There is water slowly welling up from its top, which crawls down the side of the humidifier and falls to the floor. I am going to call for service, but I'd like to be able to describe the problem accurately. Thanks! submitted by /u/InspectorTiny1952 [link] [comments]”

“I had my central air system installed brand new (previously had through the wall ACs) in 2018. The system runs mostly ok, but the air handler always clogs at the main drain pipe which is easily cleared (I have put the EZ trap on it several years ago which has made this much easier). However, it has always had some condensation and/or leaking issues that has caused the insulation on the bottom and lower sides to become saturated. The air handler as a whole is 100% level from the outside, and when”

“So I know this pipe for the a/c condensation is usually supposed to run outside, however the maintenance team at my apartment says there’s nothing they can do. Clearly the pipe is rusted and is causing the stain you see in the picture. I clean it once a week and it looks like this in about 3 days. Do I have any grounds for escalating this issue? submitted by /u/Numerous-Thought7128 [link] [comments]”

“I just noticed a leak from a elbow on my furnace. The pipe goes up to the roof. There is a small about of rust inside the furnace by the elbow. Water is coming from inside the pipe, not the ceiling. It is a 2025 manufactured home. Do I need to call a roofer or hvac? Thanks. submitted by /u/DJT90 [link] [comments]”

“First time posting, hope to get an opinion or two from the group. We do intend to bring someone in this week to look at our system, but I am unfamiliar with how these units function and would just feel better about having some insights. Our issue is that in the past two weeks I've noticed a buildup of moisture around the base of the HVAC unit. Second picture shows what it was initially, but then it was to the point where the wooden base support was saturated and water was pooling in spots. O”

“We’re transitioning from AC to heat and there’s a strong fresh mold smell when we start the heater. No smell at all on regular fan, cool or dry mode. We have a Senville ducted system. I’m assuming the drip pan needs to be cleaned but I’m not sure how to access it. The installer is out of state. I imagine it’s behind the panel where the pipe going to the condensate pump is. I’m not 100% sure how to open that panel though since there are also coolant pipes installed in the panel. Any advice?”

“Pics are from today. Moss and algae growth make me think this has been happening for a while, though this is central FL and outdoor humidity has been between 75-93% for at least a month, between 85-93 for 16+ hours a day and the unit is in the shade nearly all day this time of year. Noticed water pooling under the compressor side a few days ago. Checked the condenser drain line and it was dripping steady, pulled the whole drain line off at the fitting and no big gush came out. Past few nights I’”

“Okay so my airconditioner (window unit) suddenly started leaking so I went outside to check and noticed there was water build up, i thought it was weird and quickly after unplugging began to unscrew some parts to see if i could find where it was clogged and somehow i hit something and it started leaking gas. I have no idea if its flammable or toxic, i tried calling dozens of numbers but none of them respond. Is this am actual emergency? Does anyone have an idea of what gas it could be? I already”

“anyone fix the issue with loud dripping sound?”

“This L-shaped PVC pipe is high up on the exterior wall of my house and I noticed water dripping from it. The AC has been running. Is this likely the secondary/emergency condensate drain from the AC coil? If it’s dripping, does that usually mean the primary condensate line is clogged and I should check the drain pan? I’d say about a gallon or 2 of water has been dripping from this for the past 2 hours or so. submitted by /u/drewskyoosky [link] [comments]”

“I had a company out recently to replace the AC motor on an ~8 year old unit. They did the work, but after they left, I started to hear and see a constant dripping of water from our emergency pan. I called the company back and after inspection, they stated that someone probably stepped on the drain pipe and cracked the pan. They showed me how the crack is right at the drainpipe exit from the pan. Unfortunately, it's a pretty big crack. Nobody else has been up there other than me and them. I o”

“We have a business in an old building, we rent. We lost our lease so we’re only here another month, but the issue is such a nuisance! The main vent is constantly leaking from all the condensation on it. Any temporary fixes to make the last month of service here more enjoyable? submitted by /u/princesspeach3789 [link] [comments]”

“Hey Fam, this seems bad to me. Please let me know what’s up. Woke up to water around furnace. The heat has been off since last year, just turned it on last night. Figured plugged condensation line but no water is coming out of it, found a leak on the other side. submitted by /u/Prestigious-Row-3619 [link] [comments]”

“I live in a “luxury building” in New Jersey. Yesterday I was inspecting my AC unit and found what appears to be a significant amount of mold and bio-slime in the drain pan and on the coils. I am concerned about the air quality in my apartment. My girlfriend has experience (light) coughing also over the last month, even though I, personally was not really experiencing any symptoms. Can you confirm if it is indeed mold?! Should I ask for compensation for bad air quality in my apartment? What do yo”

“I purchased a house in Dec'25 that was flipped and had an Air conditioner installed in HVAC in the attic. There was no secondary drain pan that was installed (not up to code). This was not caught by my house inspector. This summer, our living room ceiling collapsed because the AC pan was on a sloped away from the drain. My wife and I were denied by insurance, quoted $8500 for mold remediation, and ended up taking it upon ourselves to clean up the mess. We were able to get in touch with the H”

“Recently my ac stopped working and the maintenance team told me it was completely damaged from the inside and outside so they had to replace it. While he was working I went to go see and saw the inside of the wall, I’ve been smelling mildewy scents when the ac turns on but didn’t think anything of it, now that I seen the inside I’m worried. submitted by /u/Fantastic_Driver816 [link] [comments]”

“The AC was installed before we bought the house. Serial number shows it was manufactured in 2018. I notice a good amount of water is pooling on the filter. I can confirm that drip pan is new, and drain pipe is not clogged. The first tech peeked into filter slot and told me the coil is dirty, probably because previous owner didn’t have filter in place for a long time. The airflow is restricted, thus water drips down instead of flowing into drip pan. He said I need to find someone specializes in p”

“This is one of three AC installs me and my company have done in the past six months. I installed the one pictured, another team of installers did the other two. I have had callback after callback from condensate pumps tripping GFCIs and I cannot for the life of me figure out what is going on. I've changed out pumps for new ones, tightened electrical connections, re-run the vinyl tubing, straightened out peaks and valleys, tested the pumps and gfcis, re-run the PVC to drain properly... ANYTHI”

“Buckle in this one's a long one. Back in july our ac started leaking like crazy, with a brand new filter I had installed the weekend before. So I get to researching, the ac is working fine just dumping water, i run warm water and vinegar down the line with the ac off it drains out the other end (out the side of the house) I find out our ac doesn't have a p trap, so I install one, its alittle janky but it works, ac stops leaking. For a week, then I come home to it completely frozen, so I”

“It’s that musty, damp, earthy, pungent type of smell. Had the ducts cleaned this morning. Headaches, nose running, memory shot, difficulty breathing. I have had odor issues for years. I’ve been here 6 and it hit its peak this past spring. Landlord ignored me until I finally sent a formal letter. Maintenance did an air test two weeks ago and refuse to answer my several inquiries on the results. This morning an hvac company came and sprayed a sanitizing chemical. The pictures in my post are prior”

“Hi! Unfortunately we have been fighting with our ac for months. The apartment keeps putting bandaids on the issue rather than fixing it. This leak comes and goes with almost no rhyme or reason. The float switch also fills up randomly, which of course means the unit stops blowing cool air. We’ve had it looked at so many times, but maintenance is much more focused on the outdoor unit, other than using a shop vac on the vertical pipe. Could the angle of this pipe be part of the issue? I noticed it”

“i’m not sure if this is the place to ask, but i needed someone who KNOWS shit to tell me how to clean this. some background: i live in south louisiana, my house is old and uninsulated, and mold loves growing in my fuckin house. i’ve had this ac for about two years. i cleaned it out at the start of summer and i regularly wash the filter, grills, and visible parts. i shined a flashlight in it because i’ve been feeling weird and achey for no discernible reason and now i’m freaking out. my living ro”

“About a year ago we had a possum die right under the HVAC supply trunk while we were out of town. When we came home the smell was awful and we couldn't run the AC. I literally had to send the wife and kids away. It took us all day to find the possum, or what was left of it. We were certain something was dead in the ductwork somewhere, so we were opening it up in all of the joints to check. Because I was working fast, I did a pretty quick tape job to put everything back together. Cut to about”

“Came home a few days ago to water on the floor following it to the issue we found this pump overflowing and leaking. Tryed taking it out and cleaning it out but it flooded again the following day. Tried to flip the switch manually and had no response. Planning on replacing it. Now I'm not use to doing all this so I wanted to get some advice and info from people with knowledge. First question. This is basically a pump to push excess water to the drain right? It doesn't pull water out righ”

“My AC unit recently has started releasing this awful, strong, musty smell. Probably back in March/April timeframe. We noticed it smelt really bad when we went to my MIL house and came back home. The house smelt awful. We got the a/c professionally looked at. They repaired some parts and fixed a few other things. The HVAC said all of those changes should fix the smell. Which it did for a little bit. But then about a month after the smell returned. My husband fixed some small holes in the ducts in”

“We bought this house and moved in about a year ago. Today my husband was in the attic to change the air filters (two AC units) and he noticed a gap where this copper pipe is going into one of the units. He says: I think that this is the pipe for the refrigerant coming back in to the ac unit after its been to the outside heat exchanger because it feels to cool to the touch (but I'm probably misusing some terms here). It looks a little off center, leaving a gap on one side, and on the other si”

“Upper level AC started to short cycle and I shorted the Y and R pins to turn the AC, while going out to the yard I noticed the spill pipe leaking. My units are in the attic on the side of drip but I can't find the AC drain anywhere. Where to look. Attaching the video of my outside fans below. TIA submitted by /u/MartinelliG [link] [comments]”