Keep finding these little blue bits in the water, tap strainer, dishwasher inlet filter, toilet filler. As the toilet and dishwasher are on cold feed only suspect nothing to do with the hot water. All plumping relatively new (10 years max) and mostly jg speedfit plastic. Concerned they may have fouled the thermostatic mixer on bath and showers. Any idea where they have come from, is it likely to be something in my property or from the mains water in?