I would like to add to the other answers, it will be better if you use expressions like "està lloviendo a càntaros", or "està diluviando", since those are more common expressions than "llover a màs y mejor" or "caer chuzos de punta" or "llueve a mares". In fact, if you say something like that in Argentina, you will look like a crazy dude, and with the "chuzo" expression... well, the word doesn't event exist here.
So, stary with "lloviendo a càntaros" or "està diluviando" (or simply "està lloviendo mucho"). It's far more neutral.
Huge!