For a while now I have been removing and cleaning all the screens in every faucet in my house. They become filled with chunks of what I am guessing is calcium. I even had to replace the internal valve on my upstairs bathroom faucets. Our kitchen is the worst, it needs to be cleaned many times a day. We have a Rheem hot water heater, unsure of the size or age. Is this only from the hot water, or is there somewhere else I should be looking? Also, how do I stop this, it is quite annoying?