Last night I walked in and noticed I've have a leak in the corner of my living room so I looked for where it was coming from and on the other side of wall is a closet with my central air unit and my hot water heater, neither are leaking directly.

I notice the water was overflowing from a PVC pipe in the floor (what looks to be a drain) but has a pipe from the hot water heater and a pipe from the central air unit leading down into it.

It doesn't seem to be overflowing constantly--I had it pretty dry last night and my wife took a shower this morning and it started overflowing again.

Why would this be happening?

  • 3
    Is the water coming out cold or hot? Aug 9, 2020 at 17:54
  • 4
    its coming out cold.
    – Dakota
    Aug 9, 2020 at 18:24

3 Answers 3


Though a photo might help, from your description, this is most likely a drain, as you surmised, meant to take the flow from the water heater, should the over-pressure valve pop open or leak, and condensation from the air conditioner that has not evaporated.

Since this drain receives little or no water on a regular basis, it could be blocked somewhere down the line and not be noticed. The blockage could be before the main drain pipe, and after the shower drain, so that water from the shower is backing up into the pipe and overflowing.

You might try using a drain snake from the shower, and from the overflow pipe, if you can feed it in, but since you live in an apartment, you likely would be responsible for any damage. My inclination would be to put some old towels around the pipe, and give written notice to the landlord and to the building superintendent warning them of possible damage to carpet, underlayment and to other apartments should this not be promptly repaired.

  • 5
    Yeah, definitely don't poke around in a rental. If you happen to have poor plumbing and you snake it, you can cause a leak inside the walls or ground, and that's going to be a massive amount of damage.
    – Nelson
    Aug 10, 2020 at 5:17
  • 2
    it could just be that the shower added more moisture to the air... they might not be connected.
    – Jasen
    Aug 10, 2020 at 5:36
  • 1
    Instead of a snake, start with a "plunger" action to push/pull the blockage. Since the pipe's going to be too small for a toilet plunger, try something cylindrical and a close fit for the ID of the pipe. Secure to a stout wire and use a push/pull action, varying the speed from ~5 Hertz down to once every ~3 seconds to try and get some dislogement happening.
    – Criggie
    Aug 10, 2020 at 8:37
  • My pipes don't go into a main sewer line - they just run outside. But I live in a multi-unit condo and share my drain pipes with the units above me. And there is water and other gunk from the A/C in them all summer.
    – Ed on PCR
    Aug 11, 2020 at 19:45

As a landlord myself - please please please notify your landlord. Leaks are bad news since they can cause long-term damage, and landlords usually reply quickly to leaks to protect their investment. This is also important to you in that you may risk losing some of your damage deposit if they don't know about the problem and find some kind of floor damage when you move out.

I am having a similar problem in my condo - the A/C and hot water drain into a common pipe that gets backed up occasionally due to things growing in the A/C units and getting washed into the pipe. I am on the bottom floor and the two floors above me share the same pipe. Twice, their A/C condensation has run into my unit when the pipe got blocked up below me. I have started putting tablets in the A/C unit to kill the growth and occasionally pour some diluted bleach into the drain to keep it clear. I had to snake mine out twice, but I knew where the pipes were and how they connected. If you could provide a photo of the pipes, it might be easier to provide specific recommendations.

  • (former) Landlord here to second this. As a landlord, the only thing worse than a water leak is a fire. Jun 21, 2021 at 13:50

From your description of the shower causing water to flow out of the pipe, this is a sewer backup into your rental. You want to let the management know that you have good reason to believe it is a sewer backup and you should request proper remediation.

  • 3
    Even if untrue, such a complaint could speed management's response. Aug 10, 2020 at 12:46

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