01/09/2026
Does your a/c drain look like this!?
Most of the houses I go into have this basic setup.
Trap up high right off the drain pan.
Tee with no cap, allowing air to be pushed through the drain line.
This tee should have a short piece of pipe on the top of it with a cap on it. The open tee allows air to be pushed through the drain. The trap is supposed to fill with water and when this situation is present it doesn’t, and will cause drainage problems.
The second thing wrong here is that p trap is at the highest point in the drain. Plus the drain is open.
SO, believe it or not insects like spiders will crawl in there carrying debris and or building webs or nests and block the drain.
The drain will naturally get some build up in it as well because of the water that goes into it from the drain pan.
If you lower the trap to the lowest point, if water builds up it will almost always clear itself because of the weight of the water building up in the pipe.
If your drain looks like this and you have had an a/c company clear the drain because it backed up and came out of your ceiling it’s because no one looks at the bigger picture and tries to fix things. They just put band aids on.
If you want things fixed.
Call square peg.
