What to do with old water pipes after removing a fixture?
Leaving inactive water lines open creates serious risks of accidental leaks, child tampering, and stagnation issues like dead legs. You need to properly secure and cap off these leftover secondary pipes using appropriate fittings or soldering to prevent future damage.
What the numbers show
Counted from the threads quoted below. How we count
- This comes up 14.9× more often in r/HomeImprovement than across the site as a whole.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
Found another way around this?
Share your steps and trade-offs so fellow engineers don't have to reinvent the wheel. No account required.
What to do with old water pipes after removing a fixture?
- 1leaving the bidet installed and making use of itDid this help you?
- 2leaving the pipe as-is in case someone wants to set up a bidet againDid this help you?
- 3tracing the pipe back and removing it lower downDid this help you?
- 4leaving the pipes capped and unusedDid this help you?
- 5considering installing a small basin on the top floor to regularly flush water throughDid this help you?
- 6Asking the builder to cut the pipe shorter and make it flush with the wallDid this help you?
- 7Installing a recessed access panel or cover over the cleanoutDid this help you?
- 8Using makeshift pieces cut up to fit the gapDid this help you?
- 9Glue a 45 off of the t y fitting to bridge the gap and avoid code violationsDid this help you?
- 10leaving the vent out the roof and sealing the end of itDid this help you?
- 11sealing up the openings created by cutting it apartDid this help you?
In their words
Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.
“Does anyone know what this is next to the bathtub and why it sticks out so far? Is this normal, or is it something I should ask the builder to fix/make flush with the wall?”source ↗
“Am I correct that this has in effect left a 4m dead leg of pipework from the two branches that come off the middle floor, and also a nearer 10m dead leg of pipe from the ground floor branch that is meant to supply untreated water”source ↗
“Can I safely just leave things as they are for now after swapping the hard and soft and getting the toilet sorted?”source ↗
“Or is there something we need to be doing proactively to sort it?”source ↗
“So my question is, can I just cut this out, seal it up, and help make more room for myself and new plumbing without impacting the rest of my plumbing system?”source ↗
“I removed the InSinkErator to just put in a normal drain and now there is an offset I need to address.”source ↗
“The main problem is that the bend coming out of the p trap needed to be like image 4 since just using a washer did not work and just kept slipping.”source ↗
“I can't really chance the pipe that is at the very back since it's glued and don't really want to deal with twisting that.”source ↗
“I would definitely cap it. I would use a bidet to do so but if you want most big box stores will have stuff to cap and seal it.”source ↗
“Absolutely cap off the pipe. You can do it with a sharkbite or solder.”source ↗
“when i remove the bidet, should i be doing anything with that second water pipe? though it will be off, it feels risky just leaving it them there, like if my toddlers accidentally twist either”source ↗
Where this came up
People with this problem also raised
- 3How to loosen bathroom water lines in extremely tight spaces
- 4How to fix a sink drain without removing the P-trap
- 2How to cap an unused gas line
- 5How to vent a relocated plumbing sink or drain
- 2Is my furnace pipe supposed to be fully sealed together?
- 2How to cover a raised sewage outlet for vinyl plank flooring