What Is Behind Your Bathroom Wall
You can find out most of this yourself in about ten minutes, before any contractor walks in. It changes how you read every quote you get.
How to tell what your supply pipe is
- Go to the basement or crawl space and find where the water line enters the house.
- Look at the colour and the fittings. Copper is unmistakable. Galvanized steel is dull grey, threaded at the joints, and often has visible rust staining at those threads.
- Scratch it lightly with a coin. Copper shows bright orange under the surface. Galvanized shows silver-grey.
- Check a magnet. It sticks to galvanized steel; it does not stick to copper or PEX.
- Then check upstairs pressure. Run the shower and flush the toilet. A dramatic pressure drop in a house with original pipe usually means scale has closed the diameter down.
Galvanized supply pipe has a practical service life of roughly 40 to 70 years. In a 1935 Ardmore house that has never been repiped, it is well past it - the question is not whether it will need replacing but whether it happens on your schedule or the pipe's.
Partial repiping - replacing only the bathroom run and leaving the rest - is common and often sensible, but ask the contractor to be explicit about where the new pipe ties into the old, because that joint is the new weak point.
Cast iron drains are a different question
Unlike galvanized supply, cast iron drain stacks are often still fine. They were built to last and many are. The issue is not condition, it is workability: joining new PVC to old cast iron requires a proper transition coupling and, if the stack has to be cut, a plumber who knows how to support it while doing so. An unsupported cast iron stack can drop.
This is why moving a toilet costs meaningfully more in a 1930s house than in a 1990s one, and why a contractor who has mostly worked on newer homes may under-quote it. It is a fair question to ask directly: how many pre-war houses have you done in this neighbourhood?
Why it matters that you know first
If you already know you have galvanized pipe, you can ask every contractor to include the replacement in their base number. Now you are comparing three quotes for the same work.
If you do not know, you will get three quotes with three different unstated assumptions, and the cheapest will usually be the one that assumed the least. That is not a discount - it is a change order waiting to happen.
Ten minutes in the crawl space is the highest-return time you will spend on this project.
Common questions
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Not sure what you have?
Describe what you can see in the crawl space or basement and we will pass it to a local contractor who can tell you quickly. No charge, no obligation.
Or call (336) 594-5048