quite a way (in a direction)

This casual expression means "quite far" or "pretty far". You use it with a direction word like one of these:

quite a way up

quite a way down

quite a way away
(This sometimes becomes "quite a ways away" in casual speech, although that's ungrammatical.)

(water) is waist deep

To explain how deep some water is in a pool, ocean, lake, etc., English speakers sometimes explain what part of their body the water reached to. To do this, they use the expression "___ deep":

Don't be scared. It's only waist deep.

Aside from "waist deep", we also use the expressions:

ankle deep

knee deep

chest deep

neck deep

out (from the shore)

When someone is swimming in the ocean, a lake, etc., you explain where they are by saying how far "out" they are from the shore:

She was swimming about twenty yards out, and suddenly I saw her start to splash and wave her arms.

You use the same phrase when someone is riding in a boat:

To catch the really big fish, you have to go a few miles out.