Hi...
A month ago I replaced the valve body in the hall bathtub. Since then, when I turn it on first time each day, the first half-cup of water is brownish. Then it clears. This happens with either tap, hot or cold. This did not happen with the old valve body, nor does it happen anywhere else in the house. I thought it would eventually clear but it has not diminished. I might add, the piping in the house is black iron, and I used a 4inch galvanized pipe inside the spout for the tub. I wonder if this could be an electro-chemical reaction because of the dis-similar metals. I am at a loss.

Thank you.

Phil

I don't think they are dissimilar metals. I believe you are getting rust from the inside of the pipe. Black iron house water piping? I'm surprised at that, must be a very old install. One thing you can try is to remove the spout, remove the galvanized extension. Go to HD or Lowe's and get a plastic sprinkler riser, same length and try that, they are pipe threaded.

I agree with the above answer. Yes, I would first look at the spout to make sure it has brass nipple between spout and body of the faucet - not galvanized or black steel pipe, as they are usually the cause of discoloration of water

Milo