surely 'where do you live?' can also be translated as που μένεις; can't it?
Yes, it can. It's added!
As other people have already asked, are "ζω" and "μένω" different or are they interchangeable?
They're the same for the verb "to live", "μένω" is more common and may imply a more temporary situation.
From what I gather, μένω is primarily used for stay and can mean live as in "reside". Whereas ζω means live as in "to be alive".
"ζω" also means to "live in a place" and shows a indicates it's more permanent. Look at the comment above yours.