Two campuses, and which one you are on changes where you should live. Hönggerberg is up the hill and served by its own bus.
WOKO handles most subsidised student rooms and the list is long. The private market moves in German, and a dossier written in English is read more slowly than one written in German — which in a market this fast is the same as not being read.
Apply to WOKO the day you are admitted — the list runs 4 to 9 months, so it rarely helps for your first semester, but it costs nothing and it helps for your second. Everything else means the private market.
File your residence permit dossier about three months before you arrive; processing runs eight to twelve weeks and nothing downstream starts until it is in. Register at your commune within fourteen days of landing, and sort health insurance within three months. The full timeline.
Campus is at Zentrum and Hönggerberg. Choose your neighbourhood by commute rather than by postcode — a cheaper room forty minutes away costs you two hours a day for a year.
Most ETH Zürich applicants get stuck on the same thing: an agency that wants someone resident in Switzerland to co-sign. We do that, for 3 months' rent — after we have read your file, and we do decline some.