City with hard water at a number of points (6)
'city' is the definition.
(Venice is an example)
'hard water at a number of points' is the wordplay.
'hard water' becomes 'ice'.
'at' is a charade indicator (letters next to each other) (I've seen this in other clues).
'a number of points' becomes 'ven' (I can't justify this - if you can you should believe this answer much more).
'ice' after 'ven' is 'VENICE'.
'with' is the link.
Can you help me to learn more?
(Other definitions for venice that I've seen before include "Messages", "Wonderful Italian water-city", "major tourist attraction", "La Serenissima", "Italian city once known as Queen of the Adriatic".)