What is causing rust to come from a 2nd floor bath faucet and it takes 2-3 days for the rust to accumulate and the faucet valve is new and the house is only 5 years old and no other faucet is affected?
The water heater may be rusting out. Try flushing it. This
involves hooking a hose to the faucet on the bottom of the water
heater, opening the valve for a few minutes, and then closing it.
Have the hose discharge into a bucket or a drum to see if there is
a large amount of rust. If so, you should replace the water heater.
== Answer== It sounds like they used a black nipple on tub spout.
you need to change to galv. or brass. hope this helps.