Boiling and treating water helps kill living things in water.

Anyway to remove other things that may be found in water?

What about pesticides?

And other contamination (such as oil/gas etc) that may be found mixed with water?

I didn't find much info on this site.

Any experts that can give insite to this?

You need filters for that kind of thing.

well bedepends on the chemical structure of the contaminant. Many chemicals can be absorbed by activated carbon. As for petroleum based products, well they usually float...

Charcoal picks up most of the VOCs, flocculation will get the suspended solids, and chems will precipitate out the TDS, adding other more desirable ones back in.

Distillation takes care of an awful lot of contaminants all at once, but is not a complete process. Some chems evaporate/condense at the same temp and pressure, so another treatment process is also required.

I am NOT an expert!

I strain questionable water through tightly woven cloth (to remove garbage), then run it through a 2' x 4" activated charcoal filter (to remove chemicals), then I boil it for 20 mins, let it cool down and then add it to my stores.

So most common pesticides would likely be removed through distillation and/or absorbed by charcoal? Don't know how relevant this website is but its an index of common pesticides (names and structure). Another question is, unless you're relatively close to a commercial farm, should you even be worried about pesticides in the water supply?

here's the website:

http://www.alanwood.net/pesticides/index_cn_frame.html

What about drugs? People have been flushing their unused prescriptions for years - antibiotics, painkillers, birth control.

See
http://www2.ncid.cdc.gov/travel/yb/utils/ybGet.asp?section=recs&obj=food-drink-risks.htm
for the CDC's take on treating drinking water (aimed at travelers, but applies to any questionable water).

I figure I could make myself sick worrying about all the crap in water, so I'll just add the water to my Jack Daniels.

I was assuming he wanted to be mobile. Distillation takes a little while and isn't so packable while in use, not in significant quantities.

Are you downriver?

I mostly preparing for 72 hour survival scenario. I am luck to live in colorado, so my water is fairly safe already.

My thought on the original question was if I was in new environment. Example One: Desert: Find water in tire ruts.
Second example: Water in farm field.

It sounds like avoiding the "floating" petrolium by aquiring water from the "middle" and use activated charcoal to help remove pesticides and fertilizer is a good option.