Most any tarp or awning can be hung up so it will drain into a bucket.
I know lots of folks who put pvc sink drains into their awnings and
attach hoses to them when collecting water but just hanging the tarp so
that it has a deep fold in it works at least as well. Tarps really
only work when it isn't blowing hard. Some folks with deck fills and
bulworks just stop up their scuppers and then take the fill cap off
their water tanks. Making a little dam with a towl or somthing can
help. We have a watermaker but still collect water for doing dishes
and washing blocks and so on. If you are going to drink the stuff I'd
suggest using a bit of clorine in the tanks and a filter at the sink or
a filter jug.

-- Tom.