Filter It. Kill It.
By Lilly
Dehydration doesn’t ask who you voted for! When systems fail, hydration is your most urgent need. It only takes 3 days without water for your organs to shut down, and when that starts happening, it's not a peaceful or comfortable way to go either.
When disaster hits and devastates an area, one of the first calls to action is for bottled water donations! We need water for all sorts of tasks like cooking and hygiene, but the main and most important need is hydration. And if the disaster is large enough, will you be able to rely on others to have the means to bring you safe drinking water? Do you want to wait for someone else to provide you with life or death?
Let's talk about taking matters into your own hands and how you can provide yourself and your family with safe drinking water.
The first step is by setting up systems now that you can rely on later, like water catchment and storage. I live in a 160 sq ft house and I currently only catch water on half my roof. In my area, this provides enough water for me to use in my garden, for my chickens, and for periodic summer rinse-offs in the yard. If I caught water on my whole roof and added more storage, I could easily live with this water system only, if it was necessary. Let me tell you, what great peace of mind this gives me!
So, that being said, let's focus this blog post on making water safe to drink rather than collection, since collection without knowing how to clean it isn't that useful on its own.
Briefly let's say you have a tarp, puddle, or bucket that has rainwater in it. Can you drink it straight from there? Some would say probably, but I would say better safe than sorry. Within 24–48 hours, stagnant puddles begin to harbor harmful microorganisms like bacteria and mosquito larvae. Warm temperatures, organic material like leaves, and sunlight speed this up dramatically. You’ll need to filter out these particulates and then purify the filtered water for best results.
You can’t rely on looking and smelling the water to tell if it’s safe to drink. You really need to use the 2-step system to make sure the water won't make you sick. Getting sick from contaminated water will only increase your likelihood of becoming dangerously dehydrated.
"Filter It. Kill It."
First, strain out the visible threats so that the purifiers work better. Then, destroy the invisible ones.
Filter it:
Using some sort of mechanical filter is how you will strain out the visible gunk. I like the 4 layers of easy-to-make option, but there are commercial options for sale as well. For the DIY version: gravel, sand, activated charcoal, and either a coffee filter or fine mesh cloth. See my graphic below.
The gravel on the top layer will filter out the larger particles first. Then the sand will get most of everything else. Having a substantial layer of charcoal is really the secret weapon to it all! It has a very large surface area and helps to trap and eliminate bad tastes and odors, some VOCs, some pesticides and herbicides, and some heavy metals.
When possible, purchasing true activated charcoal is going to be your best option to have on hand for consistent filtration with all the true benefits. But in a pinch, you can use basic raw charcoal, which is better than nothing. To make basic raw charcoal, take hardwood like oak and burn it very hot. Then douse it with water to get the charcoal and crush it up. Making true activated charcoal takes a few more steps.
The filter process is great and takes care of a lot of water contaminants, but this isn’t magic, it cannot eliminate most bacteria or viruses. That's where step 2 comes in!
Kill it:
For this second step, there are quite a few options, such as iodine, unscented bleach, chlorine dioxide tablets, or boiling. If you’re able to plan ahead of time, then keeping some tablets, drops, and/or bleach handy is a great idea. Also, if you have a pot, then boiling is a great option to kill off bacteria and viruses as well.
Household Bleach (Unscented Only)
Clear water: 8 drops per gallon
Wait time: 30 minutes
Check: Water should smell faintly of chlorine. If not, repeat dose.
Iodine Drops/Tablets
Clear water: 20 drops per gallon
Wait time: 30 minutes (or longer if water is cold)
⚠️ Not for long-term use or pregnancy
Chlorine Dioxide Tablets
Use: 4 tablets per gallon (1 per quart/liter)
Wait time: 4 hours to fully eliminate protozoa like Giardia and Cryptosporidium
Best for: Cold water or high-risk sources like puddles or streams
Boiling
Rolling boil: At least 1 full minute (high altitude: at least 3 minutes)
Wait time: Once boiled, it’s ready to use. Allow to cool if necessary.
Best for: One of the most reliable ways to purify water. Especially accessible in emergencies. Destroys bacteria, viruses, and protozoa like Giardia and Cryptosporidium.
With all of these methods, people often forget about the water in the threads of their container. This area can hold onto contaminated water, so after putting in whatever purifying option you use, make sure you turn the container upside down and “burp” it. Allow some of the water that has the purifier in it to bleed out through the threads. This will ensure you don't have any contaminated water left behind. And mark which containers are for purified water only so you don't cross-contaminate.
Knowing this info could help you in a disaster—or even if you get lost in the woods on a hike. Make sure to have items on hand or know how to improvise if needed.
So there are, your basics, simple, doable, and potentially lifesaving. If you've already started prepping your water plan, I’d love to hear what you're using! Or if you’ve got questions, drop them below. Let’s share ideas and help each other stay ready.
