I don't drink water from the sink because of hard-to-see hard water stains and buildup of limestone, chalk, calcium and other nasty stuff hiding under your faucet and deep inside the pipes:
http://cleanymax.com/wp-content/uploads/2015/01/aerator.jpg
Look closely under this tap to see some nasty green and white stains:
http://homewater101.com/wordpress/wp-content/uploads/2014/07/img-content-5b-300x300.jpg
http://servacint.co.uk/wp-content/uploads/2016/04/Scaled-Pipe-photo-300x289.jpg
However it doesn't really matter if you're going to boil the tap water for some coffee, since boiling-hot water will kill all the stuff floating inside it. Or, if you have a Brita jug that you clean out and replace the filter regularly.
