tap water

Several rail operators cancelled services on Monday, and Welsh Water issued a "boil water" notice to customers in 10 areas advising that their tap water may be contaminated.

Fluoridation of tap water has generated local controversies ever since it was introduced in the U.S. in 1945.

The last time the 47-year-old drank tap water at home was when she was in high school.

Some communities have been told to boil tap water to make it safe, others have seen their water supplies cut off for days or even weeks.

Over time, as these pipes have corroded, they have leached lead — a chemical with no safe level of exposure — into tap water.