Keep or replace old threaded supply piping?

With thanks to some of you in the Remodel Forum I removed all of the tiles and wet bed on the two walls of a shower curtain enclosed tub in a second floor bathroom in my 100 to 110 year old house. This exposed the hot and cold supply piping that provides hot and cold water to the tub (through one set of valves) and to the shower (through a second set of valves). The piping is not copper (except for the riser that goes up to the shower head; I'm not sure how that run of copper is connected to the piping to which it is connected, as the view of this juncture is obscured), but is, instead, piping with threaded ends. I don't know if it is galvanized steel, brass, or something else. The tub and shower water supply has worked fine during the 10 years that we have lived in the house, except that if the water in a given supply line hasn't been used in a while, and particularly if the faucet is opened wide, visible rust colored water appears, and it takes a minute to flush out and become clear (at least this is the case with some faucets elsewhere in the house; I assume it is also the case with this bathroom, which I haven't used for baths/showering). My questions are: How can I tell what type of piping material this is? Is there anything inherently problematic with threaded piping (I realize the answer may depend on what type of material it is made of)? And, should I keep it, or spend money having a plumber replace it (at least in this bathroom, where the wet bed has been removed, and the floor is coming up)? Seth.

It's galvanized steel pipe. The rust is a dead give away. Galvanized pipe was the only thing used for many years, but it ancient technology now. There a major problem with galvanized pipe. It rusts as you have seen. But, what you are seeing is just the tip of the iceberg. The rust is building up in the interior of pipe and is reducing the interior size to the point that it may be only the size of a pencil. Copper is the proven standard for replacing galvanized pipe. It doesn't rust or corrode and will last virtually forever except in some area that have a chemical imbalance that causes problems with copper. The is a new product called PEX that is being used, but while many plumber feel it is the replacement for copper, it hasn't been around long enough to real have proved itself in my unprofessional opinion. My advise is to seriously consider a whole house repipe, and discuss with the plumber the pros and cons of copper vs PEX.

I'm a fan of Wirsbo brand Pex, here is a link with some info. It's been around for about 30 years.

www.uponor-usa.com/includes/get_docs.php?id=54