Pure water freezes at 0°C and boils at 100°C. Would tap water likely freeze and boil at those exact temperatures? Why or why not?
Recall the colligative properties of freezing point depression and boiling point elevation.
Now, consider tap water. You know this!
Is tap water pure water? Of course not! It's a solution of many ions of metals or other inorganic compounds.
Hence, it has a varied boiling and melting point, by definition.