Right now I’m trying to play a survivalist character. The number one biggest pain in my butt is water. As someone born in New England I’ll tell you water is not that hard to come back in that area. Due to the very hilly/mountainous nature of the area you get a lot of little streams and what not. These being running water tend to be pretty safe to drink from. I used to do so as a child. The biggest thing I’d avoid was drinking from near anything that was downstream from a road (to avoid the run off pollutant from the road). I was trying to think of a way for survivalists to have some access to additional water. How about hole you dig will fill with water during the rain? Aka examine a shallow hole during the rain and you can get some water from it.
Also, water gotten from the funnels should be clean water, unless you are saying the rain water in the game is extremely polluted somehow…
Construction option for * Poncho or rain coat or trash bag -> Rainwater collector
Think this should be a construct instead of a deployable. Item should be solid (not walkable through) but fragile. Examine to hook a container up to it.
Also a poncho could be used as a temporary shelter from the rain. Either apply it or another * menu. It erects a small 1 square shelter for you to sleep in. Totally add poncho to the survivalist starter. 
PS: Also old-school military equipment soldiers used to have called a shelter half. One was carried by a soldier. You hook two together to make a small two person tent. No idea if that is something you’d want to include. I only ever used it in my initial training.
Not sure if this article is related but at least it’s similar: http://en.wikipedia.org/wiki/Shelter-half
Same with the soldier trainee. In basic training they drill into VERY quickly that you must drink water or die.