I've got these three pipes in my basement slab. Cast iron, 4 inches in diameter. One on the left is 15 inches from the wall, the middle is 2 and the rift one is 12. So what are these? Drain pipes for a future bathroom?enter image description here

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    As a mention, usually only the toilet pipe is 4" and sometimes only 3". The sink and the tub drain are usually only 2". The tub typically has a trap installed below the floor while the tub is being set which will take cutting out the floor a bit to set the trap and get it lined up right for the connection to the tub. There may be caps over the smaller pipe to keep the concrete out while the floor is being poured. Also the cast iron for the toilet is usually set below the floor just a bit and marked by another cap. Most of the time... Other than that, I agree with Shimon's answer...
    – Jack
    Aug 16, 2016 at 2:30
  • When I get a chance, I will get a light and take a look down each to see whats down there. House was built in 1953 and those were put in when building.
    – Scott
    Aug 17, 2016 at 13:38

1 Answer 1


Yes, most likely a rough-in for a future bathroom. Based on the distances from the walls, the leftmost one is for a shower, middle is for a sink, and right would be a toilet.

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