I live in the garden level of a six plex apartment. When some of the apartments shower it runs down the inside of the wall behind my toilet. I'm not sure if it is a broken water pipe or problem with the drain pipe. My toilet & shower do not seem to effect it at all & if I call the building owner not knowing what to say it is he takes forever to fix it. I only noticed since the wall behind the toilet got enough water damage & finally broke. The water seems to run down a large black pipe close to my tub behind the wall & is warm when I put a container in to catch the water & it only seems to happen when I hear people shower & then stops so not constant. The building has had to have the main sewer line snaked about twice a year for the last few years but I don't know if this is connected to that or not. I have two holes in my bathroom ceiling from a previous plummer trying to find a leak & it seems OK & dry up there. I have a fan blowing on the area to dry it. The wall effected is also sharred with the laundry room on the other side where the water heater is & it seems OK. Really hoping that it is something I can do something about or that the plummer does not have to enter my apartment to fix it. Once I get advice I can let the building owner know what needs fixed & get this taken care of. Just seems to happen when I hear people taking showers & the water is warm & clear. I can live with the hole in the wall as that wall will probably have to be repaired when I move thanks to the toilet in the apt above me leaking (that is fixed for now) & paint pealing. Just need the water leak figured out. Thanks.

The pipe behind your toilet and / or tub is a drain from above. It runs from upstairs bathroom and connects to other drains somewhere at your floor level or lower. Most-likely, it is an ABS pipe ( hollow core "plastic" ) and yes, it is noisy when water rushes through vertical pipe.

Shower leaks are common.The leak you have, may be a product of some other problem with this pipe. It can be a weak joint, nail hole, stress fracture, shower pan problem, shower trap leak, condensation - just to name a few. You need to call an experienced plumber to locate the leak and to repair it. Unfortunately, this includes some wall and perhaps even ceiling cutting.

Back to you

Milo

So you think it's the drainage pipe? If so how is that usually fixed & why does it not effect my toilet & tub? Just wanting to understand before I call my building owner & beg him to hire a professional plummer.

So you think it's the drainage pipe? If so how is that usually fixed & why does it not effect my toilet & tub? Just wanting to understand before I call my building owner & beg him to hire a professional plummer.

Hold on here! I agree with Milo that it's a drainage leak from the shower, but the leak doesn't have to be a drain pipe. For example it could be a ruptured shower pan or if there is a tile shower the tile grout could have shrunk allowing water to splash behind the tiles and run down the wall and into your unit. Who knows? You will need a plumber to figure it out.
The one thing I'm sure of is that you should bear none of the expense of the repair and replacing ant damage to your unit. Let me know what follows. Good luck, Tom