How To Unclog Air Conditioner Drain

A couple months ago I detailed the travels of Harold the Helicopter’s journey to the bottom of our guest bathroom toilet, and the subsequent DIY plumbing project I undertook to rescue him. It wasn’t exactly a fun project, but I did learn more than I ever wanted to know about the anatomy of a residential commode, and I saved a ton of money I would have had to find a plumber for the effort.

When a suspicious drip formed above our back door I knew it was again time to channel my “Tim the Toolman” skills and get to the bottom of it, without searching Angie’s List for an air conditioner repairman.  I soon found myself in the attic staring at a nearly-overflowing air conditioner drain pan. If you have a portable air conditioner then you probably will not have to worry about this drainage issue, but if you have central air then take note.

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Gain Some Altitude

I suspected a problem with the air conditioner drain since when the drip started it had not rained in a few days. I checked the main air conditioner drain pipe which comes out of the side or our home and noticed it was draining, but not with as much volume as it typically did. In fact, a small puddle had formed in the past and I added a piece of 1″ PVC pipe to extend the drain away from our foundation. I accessed our attic via the garage and found the air conditioner’s main evaporator unit. The pan underneath the unit was nearly full of water, which I knew was a problem. The source of the drip was a secondary drain pipe connected near the top of the pan and running to the back of our house with an exit just above our back door. I was thankful the builder and air conditioner installer put the secondary drain’s exit in a high-visibility spot so homeowners would know there was a problem.

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Shop Vac to the Rescue!

I’d been wanting to pick up a small, inexpensive wet/dry vac for small garage spills, and fortunately a local home improvement store had one on sale. I picked up a Stinger-Vac (just a mini Shop Vac) for under $30 and returned home to put it to use. Lucky for me, the Stinger’s hose attached perfectly to the 1″ PVC drain pipe and began to immediately suck out water and sludge that had accumulated inside the pipe. As it filled I simply dumped the water in our yard, reattached the vacuum and started it up again. After a few cycles I assumed I had made a dent in the amount of water from the pan and returned to the attic to view my progress. This time I carried a container of household bleach with me.

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Preventive Maintenance

If I had taken this step earlier in the spring I could have probably avoided this near-disaster, but better late than never. I accessed the air conditioner’s drain by removing a PVC cap on the top of drain pipe by hand. If the pipe was properly installed, this cap should only be tightened by hand and can easily be removed and replaced without any tools. I added a little bleach to the drain pipe to clear away any accumulated algae and mildew. Going forward, I will make this part of my checklist to prepare our home for summer.

My total material costs for the project was $32.09 for the Stinger Shop Vac. We had bleach on hand so I didn’t factor this into the cost. The whole process of unclogging the air conditioner drain took about an hour, and saved me from having to make a $50 service call to our air conditioner repairman. For a net savings of roughly $20 I am now the proud owner of a mini shop vac.

If all attempts to unclog the drain fail, it may be necessary to contact a plumber or air conditioner service professional. I recommend checking out Angie’s List to find reviews of service professionals in your area.


  1. Great job! My husband is um…not so handy, but he is brilliant on the computer. We instead befriend handy people and I offer food in exchange for services. I am a crazy lady in the kitchen and I pick people who have wives that don’t cook 🙂 Total win-win situation 🙂

    • @Amy: Way to put those culinary skills to use! Actually, I didn’t use to be so handy either. When we moved to a new town I didn’t have any “handy” friends around to bribe into helping me, so I had to start figuring things out, or start forking over megabucks for repairs. Well, you know me so you can imagine the direction I went!

  2. The last project I tackled was putting in grout after our ‘professional’ tiler/handyman forgot to do it. Before that I repainted the living room and will probably tackle the stairs this summer. I’ve also re-caulked and weatherstripped the windows. Like Amy, my husband is stellar on the computer, no so much with other stuff.

  3. My husband of 37 years has always been extremely handy, changing the oil on the cars and doing all car repairs, fixing the washing machine & the dryer, which are over 30 years old and running fine. It’s a great way to save money also a lot of personal satisfaction in a job well done.

    • @Sally: Indeed it does provide satisfaction. I rarely get a chance to get my hands dirty in my full time job, so I enjoy taking on challenges around the house! Some might accuse me of finding things to “fix” on occasion – you know, the whole “sometimes firefighters are arsonists” deal!

  4. Our recent projects (my wife usually helps out) have included repainting the entire inside of our house (it was a hideous pale pepto-bismol pink when we moved in <shudder); installing replacement flush and fill valves in the toilets, and swapping out the guts but not the shell of the fan in one bathroom. We probably saved several hundred dollars over the last year doing this sort of thing ourselves. Next up, re-sealing the shower stall in the guest bath (poorly done by the prior owner and now peeling from the walls).

    I and several friends of mine have a handyman circle. We all tired of paying such high fees to plumbers, electricians, and the like several years ago. However, some projects, such as any plumbing that involves copper pipe, require specialized skill and tools that are often not as cheap as $30. When one of us learns that skill, we become the trainer for the next project that requires it; once any of us has purchased a tool, we all know it has been purchased and now have it in the common pool of tools we have available. Worth doing with your neighbors, I believe!

  5. Our a/c unit began backing up into the house. We used our bissell steam carpet cleaner to suck out the drain. We used a wire hanger to clear it out and sucked away.

    We were elated that we were able to figure out the problem.

    We plan on suctioning twice a year from now on.

    Great post.

    • Thanks so much! You saved me about $175 in a visit that normal people should be instructed to do by the professional. So easy!

  6. I had the exact same problem last summer, but my clog was in the attic as the drain from the A/C runs into a vent pipe. I wish I had thought of using a shop vac! I ended up using a piece of tubing to siphon the water out of the pan and then removed the horizontal run of PVC to clean it out. Thanks for the tip @ the shop vac and reminding me I need to put some bleach in the drain pipe.

  7. Very impressive! Just a pointer for you (since I have worked for my family a/c company since I was about 10)…the unit it the attic is not the condensing coil, but rather the evaporator coil. The condensing coil is the large one outside.

    One more thing…it is ok drain run off to be close to your foundation, in fact it is good for it. It will help prevent foundation cracking.

    Another reason the drain can clog up is that the main house plumbing can be clogged also (depending on how it was installed) and that can be as easy as cramming salt, baking soda and vinegar into the bathroom sink attached to the main drain and flushing the line out like that.

    • @Jane4girls: I’ve made the correction in my copy above to correctly identify the “evaporator” coil – thank you for keeping me straight!

    • But why does the evaporator coil send water down the pipe when the central air conditioner is running ? Is it icing up and then melting ? Our attic unit has a pvc pipe that goes all the way to the basement, and a bucket catches any drips ~ but the water in the bucket is clean and clear, not ikky, but why does the water drain into there ? I have no idea if our main floor until leaks water like this, as that drainage pipe is directly linked to our sump pump which is underground.

      • The evaporator cools off and then the air can’t hold all of the moisture. As a result water condenses and you have to move it away from the evaporator.

  8. Great post. I love hearing about DIY projects. And I love the pictures.

    Not sure this counts as a DIY project, but lately I’ve been darning my socks and fixing other clothing items that need repair. I think I’m addicted now though. I keep looking around for other things to fix. LOL

  9. Be sure to install a float switch in that pan below the evaporator so that if the drain clogs, overflowing into the pan, the float switch shuts off the compressor before the pan fills and overflows onto your ceiling.

    In my case, the evaporator was in the basement next to the water heater.

    When the drain clogged and pudled water on the conrete floor, I thought the water heater was leaking, and so paid to have it replaced!

  10. … A cup or two of Clorox/bleach down the air-conditioner condensation drain-pipe is the best cure & preventative for clogs.

    Here in Florida those A/C PVC drain pipes clog regularly; there’s some type of clear fungus/mold (…looks like a jellyfish blob) that grows easily in those wet, warm & dark pipes.

    Copper A/C drain pipes (more common in northern states) are toxic to that growth… so it’s not usually a problem up there.

    But lots of contractors install the PVC drain-pipes without an access port to dump in the Clorox. You have to add your own PVC T-Connector & port … not a difficult task.

    Those ‘Float Switches’ that kill the A/C power when the drain-pipe clogs… are generally a bad idea, unless your Air-Handler unit is in the attic where a moderate water leak could do expensive damage. Losing A/C in Florida is much worse than a little water backup on the ground-floor/garage.

  11. i need to get one of those mini shop vacs! what I do IS take the garden hose and fit it to the pipe outside and run it into the pipe and it has helped – the sludge loosens up and runs out….slowly sometimes….I think the shop vac might work better…but the hose works too…..(you might have to do it a few times during the season….I am alone here in FLA and its terrible when I see the water on my laundry room floor! I always think it might be the washer or water tank…but its always ( so far) the clogged A/C …Now I am going to pour some bleach in there….now does anyone know how I can fix the door handle that fell off of my sliding doors?? HELP!! the screws are stripped. I hired someone a few weeks ago to fix it and now its worse…..I will have to figure it out myself and save some $$

  12. Thank you for your post. We just used our shopvac to get the water/sludge out of the pipe and then poured hot water and about two cups of bleach down the drainage pipe. Thanks for saving us some money on the repair man and for saving me from using up all my towels every day!

  13. @Thankful Central Floridian: So glad you found the post and it helped! I looked around for help when I ran into trouble and couldn’t find much. Fortunately, my AC guy was willing to talk me through it on the phone without coming out for a repair charge. I decided to pass the info along to others to hopefully save them some money, too.

    • Thanks for this info, I just fixed the drain on my AC unit. The vac worked perfect!

  14. Ok, I have tried shop vac and putting bleach down drain and have not been able to keep from ac draining into secondary drain. Do I just keep doing it or is it time to call someone. Our drain flows into bathroom downstair sink. That is where I have been trying to suck out drain. I can look down pvc pipe and tell water is backed up. Any ideas?

  15. @18option: If you have a plumber’s snake you may try running it down the drain to remove any large blockages. You might also want to use the wet/dry van to vacuum out what is standing in the pan to return the water level below the mark where it runs to the secondary line.

    If you still don’t have any luck you may need to contact your AC service provider, as the drain could be clogged at the connection to the overflow, or it might be a more serious clog. Good luck!

  16. I have a central Florida AC unit too and I was told just today by an AC company that owners should flush the condensate line with warm to hot water and vinegar every month!

    After reading several posts online I see that it is important and I partially drained the line.
    There seems to be some disagreement about the use of bleach in PVC though.

    Any thoughts?


  17. @BeDammit: I have since discovered some of the same concerns with bleach. Vinegar is probably better for your environment, depending on where the line drains out. For instance, ours spits out into the yard where I’d rather splash a little vinegar. Good suggestion!

  18. Re: How To Unclog Air Conditioner Drain

    I thought the water on our garage floor was from the car a/c until I realized otherwise!!

    This was a great tip, THANK YOU !!

    I would add that I have a Ridgid shop vac with a 2 1/4 nozzle, so I fashioned an “adapter” out of a Sam’s Club drinking water bottle (the hour glass shape). I cut the bottom off the bottle and found this was a snug fit on the shop vac, with the cap end of the bottle being an equally snug fit in the drain pipe PLUS I had the added advantage of being able to SEE exactly what was being sucked out of the drain line.

    Thanks again.

  19. My father-in-law has a secondary drain ( air conditioner) that drips a lot of water onto his backyard lawn. He likes to catch it in a bucket to use to hand water his plants. My question is this…
    Can my dog get sick from drinking this water? Is this water contaminated?

  20. @Linda: I’m not sure about the possible contaminants in the water, but it’s possible the water is not safe as it may have various components of the air conditioning system in it – freon, pipe debris, rust from the pan, etc.

  21. My drain is clogged as well, however the primary drain goes to a bathroom sink, and the secondary drain (where water is now dripping out) sticks out of the roof on the second floor. Any idea on how to unclog a primary drain that goes to a sink?

  22. Last night my husband and I noticed our AC wasn’t working as it normally does do I suggested changing the filter. It was absolutely filthy, but what made us more upset was the fact it was soaking wet. We turned off the AC and I did a little research on why water would be dripping and we figured it was the drain pipe (even though I regularly put bleach in at the T – actually did it on 6/10/09 same as the last filter change). Anyway, my husband and I set off into the night with a flashlight looking for the exterior drain and we couldn’t find it. there are no exterior drains coming from our home besides the one for the hot water heater relief valve. We decided to do the shop vac at the T to see if that would help. We ended up with approx 2-3 gallons of water and trash. Should we be concerned that we are unable to locate the exterior drain? Or should we just continue to use the vac at the t pipe inside if this happens in the future?

  23. @Rebecca: While it’s good you were able to put the shopvac on the “T,” I worry that you may be pulling any blockages back up the line. If you can’t locate any exterior drains check around bathroom sinks – builders have been known to drop them there (see a couple examples in comments above). It might be possible to loosen/detach the AC drain line from the primary sink drain and shopvac from there. Bleach or vinegar with a warm water flush should help as well.

  24. Great tip! I’m renting and i just noticed that my lease says I’m responsible for dealing with A/C drain line clogs! I about freaked out until I found your post.

    Now, mine’s a little tricky. The system is old, and the drain pipe is PVC and comes out of the unit (in the garage), then disappears down into the slab. The whole system is sealed and glued (I assume by pvc glue), so there’s nowhere I can access the line to try sucking anything out. Should I cut into the PVC pipe and try to suck/snake it out? Just had a baby and it’s August in central FL so AC is pretty important. Thanks!

  25. Tom in WP – Mine goes straight into the floor too, but I do have an access port for pouring bleach in. My husband and I looked at every other drain in the house, even behind the bathtub, and the drain pipe doesn’t connect to any of them. we believe it has it’s own drain. I unclogged ours the other night by pouring about 1/2 cup of baking soda followed by 2 cups of vinegar into the T pipe (after I used the shop vac on it). I can’t remember the website I got that tip from, it may have been this one, either way, it worked perfectly!!! It might be a good idea, if you are going to have to cut into the PVC anyway to add on an access port for bleach or baking soda and vinegar so you won’t have this happen again…if you are planning on staying in the same house for a while. Good luck.

  26. FIXED – Sorta…

    Tried shop vac sucking and blowing on any and all available pipes exiting the house – no dice.

    Then, escalating the destruction, I drilled a good-size hole in a high point on the drain pipe near it’s exit from the AC unit. I figured if I was going to wind up cutting the pipe off, this couldn’t hurt. No water came out, so I stuck the curly-q end of an undone wire clothes hanger down the hole – it came out wet and covered in goobies. So I bent a 90deg bend in the other end of the wire hanger, shoved it into my drill, worked the rest of the wire hanger down into the hole, and commenced to give the begoobied pipe a good internal scrubbing. poured some water down in the drain pan, and it drained right out – success!

    I did pour some chlorox in there too, and will add some more later, along with some hot water and vinegar and baking soda.

    $0 total out-of-pocket expense so far. Thanks for all the help!

  27. I found water dripping from both the pipes outside our house and the one upper on our front door. Any one here have an idea why this happened? I have tried the tips suggested here before and it worked but not this time. Any suggestion will be greatly appreciated.

  28. I have had continuing problems with our AC units in the attic draining through the same drain as the upstairs sink. I was putting algaecide down there once a month, forgot last month and it backed up into her sink. I am guessing there is a trap below her sink on the first floor that is getting clogged? I have a snake I run down there and it clears the clog. I like the baking soda and vinegar idea, this creates a foaming? How often do I need to do this? Our AC runs almost year round in Houston.

  29. Here is a story.
    My Inverter Air conditioner has 2 drains out that drain to a downpipe connected to the guttering. Well the downpipe got clogged and the water went up the drain pipes of the air-con into the unit and leaked all over the floor in the house.

    After removing the drain pipe from the down pipe (to stop the flood inside the house) I am scared to even start the air-con in case its electrics have been damaged.

    I wonder if the water that went inside it will just drain out again.

    I plan to let it dry out for a month. And then turn it on.

    I wonder if I can claim on insurance if it doesn’t work anymore.

  30. I pretty much have the same problem, clogged air conditioning ducts. I’m pretty handy and I love to troubleshoot and when all else fails I “GOOGLE”! lol, of course I finally found where the water was coming from and I stumbled upon this site. Who ever thought of offering this information to the public is a great person and will be blessed. Me and my family are thankful for your intel.

  31. Thanks so much. I came home from work (after dark) to find my wife & son outside w/ a neighbor: part of our tree was falling down. Then my son noticed the AC was dripping into the bathtub, but NOT through the drain pipe. Great!! Anyway, after poking around, trying to figure out how to open the drain pipe, your tip was found. After hooking the shop vac up, it wasn’t 3 seconds & the pipe was open & now all is well. Thanks.

  32. We just had water leaking from our upstairs ceiling. Upon investigating in attic ac unit found drain pan full. Actually it was half way full and was leaking out of a knock-out hole in drain pan. I can not find a drain line coming from the pan. It looks like one was not installed during construction. This is either the third or fourth year of ac usage. Does this sound feasible. Thanks, Pancho.

  33. Just moved into a house that has central air. Seems to be working fine but have noticed the pvc from the roof sometimes drips a little bit. Not sure if this is the primary or secondary line and how do I clean it with a shop vac since it’s two stories up. Was in the attic last week and couldn’t see the drip pan. It may be under the floor boards because it appears the unit lays right on the floor itself.
    I think I could take care of it myself.

  34. Do I need to dissconnect ac while using the shop vac/ adding bleach? Also should there be a removable cap on top of the condensate line?

    • I did not disconnect mine, but I suppose for safety’s sake it might be wise. Our system had a removable cap at the top of a “t” joint in the drain’s PVC line.

  35. Hi, My Primary condensate runs to my bathroom, under the sink. Is it ok? to wet/vac (suction) the primary line up in attic?

    Update: I suctioned the primary line in the attic and it seemed to work for a while, however this morning I noticed my secondary drain, located over bedroom window was dripping again. Could it be that the clog is closer to the line connected to the bathroom sink? Can I remove the coupling that is connected just above the fixture (on sink) or would that be the extremely messy route? Thanks again….your website is extremely helpful!

  36. Thank you, thank you for this post! We just bought our first house (a foreclosure that has been A LOT of work), and are rather clueless when it comes to home repairs. In the past, we’ve just called the landlord…but we can’t do that anymore!

    Anyway, I was outside taking out the recycling when I noticed that the water wasn’t draining as quickly as is should from the A/C drain pipe. I went inside and poured in some bleach, but it didn’t drain. It was at this point that I freaked out a little. I imagined huge repair bills, because even a service call is outrageous, and I was wondering how I could possibly pay it right now; I just bought a new couch for said house, and my kitten is being neutered on Tuesday, but I digress. I was lucky enough to own a shop vac, which I purchased a couple months ago to vacuum tile dust out of my garage from our total house re-flooring, and the bleach was free too, thanks to a robust supply of laundry products.

    I dumped my shop vac’s mini-bucket twice and the sludge was quite a sight. The bleach and water I dumped in drained perfectly- tomorrow, after the bleach clears a little, I plan on dumping some vinegar and hot water down the line, and I’m adding this to my monthly chore list. Can you flush the line too often? I live in Orlando, FL., and algae and sludge is quite a problem in our humid climate- would vinegar/hot water twice monthly be too much?

    Again, I can’t thank you enough for saving me money! You rock.

    • Don’t think you can flush the drain too often, but it may not be necessary as often as monthly. I’d probably just add it to my spring/fall to-do list to catch the beginning of the AC high-use season and the end. I live in the south, too, so I recognize AC is nearly a year-round luxury to combat the heat and humidity!

      Glad I could help!

    • I just added a couple of spoons of Drano on the top of the condensation pipe. It got cleared and water stopped running out.

  37. My air condition unit had this problem with excessive water. I took the steps to unclogged my drain valve located in my 2nd bathroom. The PVC pipe was clogged with some pretty funky stuff, so I blew it out into my Shop Vac. Thank you for the information

  38. THANK YOU SO MUCH!!! Once I read your article and looked at your pictures, I knew exactly what to do. You are so totally awesome 🙂 My drain pipe was totally clogged with mud for several inches. It is just an opening in the wall with no pretty pvc piping, but once I noticed there was no pvc piping, I saw the opening in my brick. I know I didn’t do everything just right, but I think it is totally clean now. I used a spoon and bendable haxsaw blade for length to dig out the mud. I made sure the blade was NOT facing the direction I was turning it. Once I finally saw a good amount of water in the mud, I used my rainbow vacuum cleaner’s water suction hose to clear out the rest of the muck. I may have messed up by spraying water into the hole, but I wanted to make sure I had it cleaned out totally. After spraying the water, I suctioned out the water again with the rainbow until it quit pulling “stuff” out. The two pipes at the air handler were not backed up, but there was a small puddle where condensation had pooled. I had noticed last year that water was dripping from the air handler inside, but didn’t realize that was a problem until I read your article. I didn’t even have to make a trip to the hardware store. So cost was $0.00!!!! You have made my weekend a happy success. Thank you again!

  39. Some info I read on another site I found for you guys is that if you use copper pipe for your AC drain, then the bacteria the copper produces kills the harmful bacteria that casues the sludge in the pipes. Alternatively, put some copper coins in the AC pan and let the good bacteria flush through the system killing the sludge bacteria. Much the same idea as putting a copper strip across the ridge of your roof to kill the moss.

    -Good luck


  40. I’m going to have to do this to my unit in the morning. I have a regular shop vac…if the hose on it isn’t the same size as my condensate pipe (which I am fairly certain it isn’t) can I use duct tape to connect the hose to the pipe? ?

  41. I really appreciate this tip. I had an old dirty sock smell running through the house. I had people trying to explain the process but your site. What a helpful resource! Thanks so much. Now I know yet another simple tip for doing keeping the A/C in top shape during the humid months!!!

  42. Thank you for all this wonderful information! We have an attic unit just like in your pict, but the drain pipes go back under the unit towards the gutters. I can hear a very loud DRIP DRIP when I stand outside of my front door, how can I figure out where the pipes drain? My husband wants to call the a/c peeps, I want to fix this myself 🙂

  43. Awesome article. I seldom make it down to the basement where the A/C unit is, but tonight I came down to a minor flood. After reading your article, I had the drain unclogged in a matter of minutes. Took the preventative measures as well by removing the PVC cap and dumping hot water and bleach to remove sludge. Thanks so much for the advice.

  44. So I assume from reading all of these helpful posts that I might have a clogged primary condensate pipe. We heard water coming from outside of our bathroom window and after investigating saw water coming out and a wet outside wall. Following this went into attic and saw some water in secondary pan. Did not see a T-in the PVC pipe but had a blue cap, which I am guessing is the opening to the primary where I can pour hot water and bleach into?? I followed the primary line and it does not go outside, but seems to go into the guest bathroom. I looked under both sinks and did not see any additions to the p-traps of the sinks? so I assume it goes into the bathtub? My question would then be how do you wetvac out this when it goes into the bathtub? there is nothing I can see? Do I have to do it (wetvac) nearest the system in the attic where the blue cap is? Should I try a snake? Any help would be appreciated!

  45. most excellent . I wish I’d seen this before I took off the front panel of the a/c unit and used my wife’s turkey baster to suck the water out LOL.
    I went and sucked the line dry after seeing this post. I have the same wet/vac….perfect…thanks.

  46. Just purchased Stinger at Home Depot (not available at Lowe;s) for $29 and connected to outside a/c pvc drain pipe. In only 2 minutes the clog was resolved and the line was cleared! Will now repeat this exercise monthly to keep a/c drain pipe clean. Best $29 I ever spent!

  47. for $2 you can buy a can of compressed air and blow the line clean from the end of the clean-out…

  48. Thanks! What a life saver. After dealing with a crooked incompetent service tech and apathetic insurance company, this took me five minutes and made my day.

  49. This was a lifesaver! We had a small puddle of water gathering by the furnace. I knew it wasn’t chemical, but at first I thought it was our humidifier, which drains into the same PVC pipe to the floor drain. The water to that was turned off in the spring,. We don’t have an outdoor drain at all. (I looked everywhere) but there was two PVC pipes coming out of the unit just below where the copper and rubber wrapped pipes from the outside unit came into the blower. One of the pipes was open, so I used a shop vac with a clog removing attachment (YESthis exists, it’s at Lowes and it’s awesome- like a plunger and is used for small drains and pipes!) and sucked out all the icky water and got a bit of algae. I poured some bleach water down that same pipe, and the puddle is drying! I plan to watch it though, because I am not sure I got it all out.

    The better news is I have a slow drain in my bathroom and my new attachment will help me deal with that too!

  50. So I had an AC man out today and he cleaned out the pvc pipe that comes off of the air handler unit inside a small closet on the first floor. There was a clog both in the pipe and in the tray too.; Now tonight I realized that the floor drainis backing up and overflowing? What do I do? Snake it? Shop vac the waterout? Right now I have the pvc pipe draining into a 5 gallon bucket.

  51. Thanks for posting this help yourself! I got home last night to find my home feeling like a furnace “87 degrees”.
    Believe me I was desperate, maybe more for my animals than for myself! As I did not have the vac you have ( I will as of tomorrow) I decided to do the next best thing you mentioned, poured some Clorox down the drain. Did it help? YES but maybe temporarily until I can suck out what ever is clogging it. At lest I can sleep tonight!
    thank you again soooooo much!

  52. I fill a cofee mug with 1/3 Clorox and 2/3 water. Heat for 1 minute in the microwave and pour it down the AC drain. It is about the same temperature as a cup of coffee and loosens everything in the drain trap until it is slowly diluted by the condensate.

  53. My primary condensate line runs from the handler in the attic to underneath the bathroom sink below on the second floor (the secondary back up line exits above the front door on the porch). I am wondering if I can use drano in the line to clear buildup rather than a shop vac? It’s not clogged yet and is not backing up into the pan or exiting at the front door, but I can hear a gurgling sound so I suspect it’s starting to build up.

  54. REALLY appreciate all the sugs on how to resolve this simple but ac defying issue. I’m in FL and its hot buddy and the ac people are -well y’all know-. So I tried the shop vac thing and nothing. The idea of blowing I read up in the comments I can’t imagine it working. Saw a youtube video of a guy rigging a leaf blower to it using a gatorade bottle as link tween the two — and it worked! Made me think, hmmm, pressure’s pressure, man, so I got the garden hose and and duck taped it real good to the pipe trap (where you pour in the bleach )next to the sensor trap coming from the unit in my garage (the pipe goes under the foundation and out by the trash bins) . And went out and turned it on full blast and Boom , stopped up drain be gone!!! Godbless the internet — and my mama for breeding me clever.

  55. My dad invented a new tool that unclogs condensate drains and it’s really really simple to use. It works a lot like a plunger, and doesn’t require any set up time in most applications. You just insert into drain, pull out, then the suction “pops” the clog, and it all just drains out. It is called the “clog popper”

  56. As electricity prices keep rising, it’s more important than ever that appliances are as efficient as possible. Air conditioner efficiency has improved year by year thanks to the government’s Minimum Energy Performance Standard (MEPS) program, but cooling and heating accounts for about 38% of an average household’s energy usage; that can add up to hundreds or even thousands of dollars over a year. As electricity prices keep rising, it’s more important than ever that appliances are as efficient as possible. Air conditioner efficiency has improved year by year thanks to the government’s Minimum Energy Performance Standard (MEPS) program, but cooling and heating accounts for about 38% of an average household’s energy usage; that can add up to hundreds or even thousands of dollars over a year. ..'”.

    Have a look at all of the helpful posting on our own webpage

  57. I tried this technique and it did work, however it also caused water to spray out of the unit in my attic and then water dripped down my ceiling fan in the bedroom. I had to call a repair person anyway ($100 and having to wait all day). He thinks the suction was too much so caused water to spray out of the drain pipe at the unit. I’m not sure what I did wrong, but there you have it.

  58. Thanks Frugal Dad! We were about to take a huge shop vac upstairs and then into the attic…I imagined how difficult it would be getting a liquid filled vac down without spilling the contents everywhere. I found this post, and we improvised using duct tape and our big hosed vac. It worked like a charm! Thanks again for your clever insight. 🙂

  59. I had a similar problem with my AC unit. The repairman blew out the drain tube, added a few algae tablets, and charged me $130


  60. What’s “bleach”? Is that sold at Home Depot also? I am not sure if this matters with electric.

  61. I have had two unsuccessful service calls to pinpoint the problem with my AC gurgling and never kicking on. Can turn it off and back on and works fine until later in day or middle of night it decides to not kick on again. After wasting money on service calls, I looked at drain pan and has some water and sludge. Does anyone know if cleaning pan/line out (will do this anyways) might be beneficial to the unit not kicking on /gurgling?? Please help.

  62. The condensate drain is clear but there is water at the base of the air handler. It was a 90 + degree day and very humid. Could a dirty filter cause this?

  63. My apartment’s air conditioning has been leaking for days. Today (a Sunday!) it was water everywhere coming from the condesation pipe. I cleaned it up with a hanger,didn not work. Then I went to the supermarket, got Drano and got a little bit inside the pipe. Water stopped!

  64. Yes, I’m another one that has a lot of problems with my a/c unit but I found out that sucking out the both lines coming out of the house is a must but you can get bleach tablets from Homedepot in plumbing or by a/c units to put in your a/c unit drain pan keeps slim or slug at bay………

  65. We live in a mobile home in Texas. We are experiencing excessive mold buildup on our a/c unit’s coils. They are black with mold. We bought some foaming a/c coil cleaner from hardware store. Cleaned part but still have a lot of mold left. Will pouring pure bleach on coils clean this mold off. We even brushed gently on coils. The mold smell in the house is terrible.


  67. Found mold growing inside my linen closet yesterday and wet carpet in the back corner of the closet as well. There were no pipes nearby, so I suspected a roof leak. My hubby went up in attic and found the a/c unit pan overflowing with chunks of insulation floating around in the pan. The water had soaked down into the wall of the closet. What a mess! We drained the water from the pan using the shop vac, then tried using it to suck out the line and nothing budged (yup, there was insulation in the pipe causing the clog). Finally pulled the hose up into the attic, inserted it into the pipe (sealing carefully so no water would back-up into attic) and turned the hose on. It worked! The chunk of insulation was flushed right out. The pipe terminates under the eaves on the side of the house. I actually have 2 a/c units, one on each end of the house, so we will be checking the pan on the other unit tomorrow. We still need to have the mold removing folks (Serv Pro) come out to remove the drywall and repair the damage to the linen closet and floor. I’m considering having a float switch installed in the drain pans as someone previously suggested. Since we have 2 units, having 1 shut off wouldn’t be a critical problem and it would certainly be preferable to dealing with mold in my walls! Thanks to everyone for all their helpful suggestions and insight!

  68. I’m soooo happy I found this site. About 5 days ago my niece heard water running. Immediately my heart sank because I knew it had to be a clogged a/c drain. I work and usually let the ac run so it’s cool when I come home. I had just changed the filter a couple of weeks ago. Water had soaked the wood holding the ac unit and water heater and had soaked the new filter. It took 3 days to completely dry out. (Thank goodness I bought 2 filters at the time.) Now to deal with the real problem. I have a “t” connector and pvc pipe goes into slab in concrete beneath closet. Tried the blow thing to dislodge the clog (covered it as I’m a germ-a-phobe). LOL. It didn’t work. Anyway, the thought of dragging the hose in and possible more water totally freaked me out. Well, thank goodness I read this site. I went out and got baking soda, white vinegar, Clorox, and salt. I was going to try Everything before the hose or had to call a pro. Clorox first: got a mug, poured it almost full, covered and heated for 1 min in microwave ( saw this posted by someone here). Cut a cheap water bottle as funnel and poured into “t”. The Clorox came up where I could see it and I got nervous. Figured it was going to take 8 hours (another hot night). Well, to my surprise as I was closing the closet I heard gurgling!!! Woohoo!!! It worked. I poured a mug of hot tap water into the drain and again heard it run out. Yay! Thank you all. I’ll now make sure I routinely use the Clorox.

  69. for those of you guys who can’t easily get to the drain end of the pipe, remember and good shop vac also has an exhaust port that you can atach the hose to, this allows you to BLOW out the pipe from the “t” junction just add a paper towel wad to prevent the air from escaping on the drain pan side.

  70. I just rented a house in Florida. The real estate company just sent all of its renters an email about pouring bleach down the bleach port every month. They also said if we fail to do this every month we would be responsible for damages that could occur inside the house, (water damages).

    I have a single family home, 1 story. There is a door in the garage that houses the main part of the central air. I can’t find any PVC vertical pipe to pour the bleach down. I did find a small hose outside next to the compressor that is laying on the ground.

    How can I make sure the drain is kept cleaned without a bleach port ? Can I try and clean the drain out by attaching a shop vac to the hose that is outside the house ? Thanks