Rusty water from new handshower installation

We had two Grohe handshowers installed in two different bathrooms, and are getting rusty water from both of them for the first several seconds of using them each day they are used. They were both installed in addition to an existing regular showerhead (with the original copper piping). A new Grohe wall union, new Grohe valves and new piping were also added (copper in one bath, plastic in the other). The handshowers were installed at the end of Aug 2008, so it's been a little while and we've used them a lot. Any installation debris should have been flushed out a LONG time ago. The problem is not coming from the handshower unit or the hose, because when I remove the hose from the wall union, I still get the rusty water out of the wall union. However, I get NO rusty water from the showerheads in both baths and the tub spout in the other bath (no tub in the first bath).

Anybody have any clue what might be going on? The installers said I just need to flush out the lines. Yeah, for how many years? That's not the problem.

If they used galvanized anywhere in the piping, this will be a perpetual problem. Often, there's a drop-ear el in the wall that gets screwed to blocking so the shower fitting stays solid. This should be brass or copper. Also, if they used a galvanized or steel nipple to get the depth for the attached bits, this could do it (it should be brass). My experience with Grohe is their stuff is well made, and I'd be surprised if it was something inside the fixtures themselves.

It really sounds like they used a steel part somewhere in the supply rather than copper or brass.

Yeah, I figured the Grohe stuff itself would be fine. Thanks for letting me know about the galvanized. I had a sneaking suspicion it might be something like that. I suppose I will have to take off the wall union and check behind it to see what they installed. Master plumbers they were not

Most plumbers only carry galanized pipe nipples.

I only carry brass on the trucks, but then I've never liked that few seconds of rusty water either.

rust

They might also have used a galvanized plug to seal an unused opening.

Thanks guys. These are all good things to check as soon as I get a chance.

Terry, thanks for the info - I figured plumbers would *not* use galvanized for water pipes, seems like common sense to me. I learn something new every day.