Cloudy tap water, also known as white water, is caused by air bubbles. It is completely harmless. The best thing to do is let tap water sit in an open container until the bubbles naturally disappear.
You can find out more about your rights by contacting the Customer Service Department at 617-989-7800 or the Collections Department at 617-989-7070. You may also download a copy of the BWSC's Billing Termination and Appeal (BT&A) Regulations.