Last summer we had our supply pipe changed outside the house because of a high iron content in the water. Ever since, the has been little specks of muck in our cold water, but it only comes of the bath tap. We've just had our bathroom done & the pipes renewd, what could be the problem?
Your bath tap will probably give the greatest rate of water flow, and this is dislodging any bits of debris still in your system. Turn the tap on as fully as you can, and let it run for quite a few minutes. Hopefully, this will pick up all the remaining loose particles and leave the water clean in future.
If you have a balanced Hot and Cold water supply to you're bath taps. Then the Header tank may need draining and cleaning out especialy if it has been disturbed with new pipe lines and plumbing works. If it is mains fed taps then since it was last summer the work was carried out then it has had ample time to flush itself out, so you need to be thinking of checking and replacing worn or perished tap washers that could be breaking up and it could be this that you are seeing. Also check any filters for damage at the mains stop taps and /or water meter if installed. If the problem persists after the above has been checked out / rectified then you need to be speaking to you're water supplier about possible water contamination.