Rain water, or Rivers and Lakes? What about the sea?
Not in a CBRN scenario.
So what can you do to make things safe?
Chemical, nothing, as filtering isn’t 100% safe without some scary machinery.
Biological, boil and boil some more.
Radio-logical and Nuclear, Nothing. Only time makes radioactive material and radio iodides safe.
Not nice right?
So what’s the alternatives?
Covered, bottled, and other sources that were out of the way of the contamination.
Pipes will be OK, at first, but be aware that they may be carrying contaminated material from further up the line.
So, can you go out and forage for what you need?
After a while yes BUT whatever you do will expose you to some level of contamination and some contaminates have ‘persistence’ i.e. everything you touch could have a lethal ‘coating’.
Chemicals generally don’t remain in the air for a long time but some nerve gases have persistence so they, in droplet form, slowly evaporate. As some material is oily, this is not washed away by rain.
Biological can be person, water-borne, droplet, and driven by the wind.
People are easy (sort of). Distance is king there. Stay away, drive them way if necessary.
Don’t forget both bacteria and viruses can live on non absorbent surfaces for as long as they remain damp (within limits of temperature and humidity).
Radio-logical and Nuclear material.
As said, time is the only thing that degrades their hazards. You can forget about the movies and fallout always looking like snow. While that can happen, fallout from a ground burst can include ‘rocks’ right down to ash and fine dust. Basically the nearer you are to the source, the bigger the lumps will be and it’s possible that those rocks will hold compacted radioactive material. Don’t forget that boom can make radioactive iodides which are water soluble. You can’t filter them easily and distillation may not work as their boiling temperature and molecular weight may be less than that of water.
What you need is thick covering and preferably an impermeable (water proof) layer on the outside. ALL OF YOU COVERED is essential.
So that’s stout footwear, head to toe coverings, ears, eyes, nose and mouth. Gloves need to be strong and also covered by impermeable material i.e. latex, nitrile, or plastics. If you can see skin, you’ve got it wrong.
Which is all going to severely affect your mobility and dexterity. With masks in mind, they can affect your peripheral vision. Not good if you are on ‘dangerous ground’.
That bulk will also reduce your ability to carry.
While you might be planning to go back for more, be careful that your exposure time doesn’t accumulate to what is unsafe. PLUS you should consider that every time you reenter your base, you may let contamination in.
Exposure time to the contamination MUST be kept as short as possible, so browsing with a shopping cart is not advisable. Bear in mind that what you are wheeling will not be immune from contamination.
Go out, get into where you need to be, then either stay there or get out as fast as you can and back into your shelter in short order.
Staying there means you’ll have to ‘move house’ only understand that anything you take outside of your shelter may have become contaminated.
Another complication you’ll have to cope with.
If you return to ‘base’, you must assume you and everything you are wearing or have foraged is contaminated.
There are plenty of military field manuals specifying good decontamination techniques BUT, if you want, I have a simple guide with which I can do a post.
As always I will stress we are taking about SERIOUS stuff here.
Don’t ever think “I can get away with it”.
Especially if someone is dependent on your skill set.
Plan carefully, work to a list, work to an absolute time limit, and NEVER SKIMP ON YOUR DECONTAMINATION TECHNIQUES.