Bits in water

[Livvi2021]

Hey, I don't know if anyone can help but I've been having bits that look like sediment in sinks and bath when the hot water runs for a while now. I've also got a light staining on my bathroom sink bowl too. It only seems to be the hot water taps and very occasionally the water has run rusty coloured too. I have no idea what this is. The pipes are copper so not sure if it's to do with corrosion also we have no pressure issues so don't think there's a leak or anything. I wondered if it could be something with the boiler (we have a combi). If anyone has experienced anything similar and any remedies would like to hear. Thank you

@PigletJohn yes it's kind of changed since we've been learning more about what could be causing it and discovering new things. From the stopcock in the road to our new pipe there is the old pipe in the pavement that is the water companies responsibility so we don't know how old that it. Then that joins to our 18 month old new supply pipe which connects directly to new pipework to our sink/stopcock (as we had a new kitchen fitted). There's other bits of pipework round the house that's old, but that doesn't explain the bits coming directly from outside to the kitchen. I'm not easily able to take any photos I'm afraid, as all the pipework is behind things (either boxed into the wall or behind cabinets /fridges).

Did you ever find out what the hard black bits were and where they came from?