DIY: Making An Activated Charcoal Filter

We’ve had a lot of rain up here lately.  A LOT of rain.  I was out puttering around the yard this week and I noticed the rain water slowly dripping through my raised fire pit and the wood coals it was full of.  Drip drip drip…… into a puddle below.

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That got me thinking, is that some kind of charcoal filter happening there?  What is the difference between a pile of wood charcoal and an Water Barrelactivated charcoal filter?  Can I make an activated charcoal filter to filter water through for drinking?

The first thing I learned when I started searching the answers to those questions, is that activated charcoal is in no way the same as burnt wood.  Activated charcoal is charcoal that has been treated with oxygen to open up millions of tiny pores between the carbon atoms.  It’s a specialized manufacturing process, requiring temperatures in the 1000 degree F range. (Or really dangerous chemicals and temperatures in the 600 degree range.)

Well, shoot.  There went my whole DIY activated charcoal plans.  What can I still do?  Make charcoal?   I’m quite the pyro, I burn a fair bit of wood.  How far will that get me towards a water filter?

It turns out, that regular charcoal was used for water filtering for a long time before we figured out activated charcoal.  In its natural state it contains the atoms that neutralize odors and filter water.  Activated charcoal just has those atoms in larger quantities. (For those interested in such things, apparently activated charcoal made from coconut shells is better than that made from wood.)

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So regular charred wood will work.  Just not as well.  You can increase the amount of regular charcoal, or increase the contact time of the water to charcoal to make up for the lesser effectiveness.  And remember, there are specific ways to make good charcoal. Check this out.

To recap here, I don’t think you can make your own Activated Charcoal, especially not for less than what you can find for it online.  And probably not safely, considering the temperatures involved.  But, if you want a DIY water filter, you can buy the Activated charcoal and DIY everything else.  You need to plan your filter to allow proper time for the AC to adsorb the contaminants, the water has to be in contact with the carbon filter for longer than a second.  You’ll also want a sediment filter before the activated charcoal filter, since they don’t work as well for the bigger particles.  Sediment filters can be fine sand or gravel.  The sediment filter will grab things like sand and rust particles.  Don’t send boiled water immediately through an AC filter, it works best at room temperature.

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Last update on 2020-07-06 at 12:08 / Affiliate links / Images from Amazon Product Advertising API

More Info

Here’s a great PDF (Click Here) from my neighbors to the North, the North Dakota State University. “Filtration: Sediment, Activated homemade water bottle water filterCarbon and Mixed Media”  If you are looking for a good overview of your various DIY options for water filtration.

They start with a good reminder to get your water tested so you KNOW for sure, exactly what kinds of things you’ll need to be filtering out.  No, this is not a service that will be available post grid crash.  Yes, you should get this done before that happens.  Then expect your water quality to get worse post-crash, not better. See Road Warrior’s post from for one of the reasons why (Click Here).

Think of your filtering needs as layers.  The sediment filter removes things like rust and sand.  The AC filter removes or reduces organics that can affect taste, odor and color, chlorine, trihalomethanes (THM), pesticides, industrial solvents (halogenated hydrocarbons), polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs).  A round of Ultraviolet (UV) treatment can be done quite simply with clear  1 L plastic water bottles set in the sun for a few hours.  UV will remove a lot of microorganisms that could make you sick, microorganisms that an AC filter won’t catch.

Check out this doc (Click Here) for a great 101 on UV water treatment.  They’ve got a great chart on UV dosages required to kill a whole list of organisms, Bacteria, mold, viruses and yeasts.

Remember to account for filter replacement.  If you want 3 months worth of water filtration, but your rate of water usage means you’ll needhomemade water filter for survival to replace the filter every 2 weeks, you’ll have to have 6 replacement filters on hand.  Your rate of water usage can be calculated by taking the Number of People x Average Daily Water Usage.  And remember to count your people correctly, will your son’s best friend who lives with a dead-beat dad be over every day?  Will your brother-in-law bring his family out to your place if the city loses water/power?  Your water usage number will be a gallons/day number.  Most filters will tell you how many gallons of water they can filter before cleaning or replacement is necessary.  So Filter Life divided by your Usage Rate will tell you how many days that filter will last at that rate.

Keep that Usage Rate in mind when you are designing the system. Do you have a place to hold the needed water, before and after filtering?  If you know you’ll need 12 gallons a day, do you want to hold 6 at a time and filter twice a day? Or hold 24 gallons and filter once every 2 days?

If you find you need some small parts, there are kits online with just those small parts that you can buy. Like this one.

Emergency-H2O Emergency Silver Impregnated Ceramic Water Filter Kit
  • 1 4X4 Silver Impregnated Ceramic Dome Water Filter
  • 1 new cloth sock (10 microns) - 1 vinyl drip tube

Last update on 2020-07-06 at 12:19 / Affiliate links / Images from Amazon Product Advertising API

What kinds of water purification do you have planned?  Anyone working on some DIY Filters?  The last time I made one was in high school, for an aquaculture class. It could be a good time to revisit that experience and see what I can whip up for my family.  Sound off in the comments below if you have ideas or actual plans that you’ve followed.

Photos by:
Brenda Price
Calamity Jane
James Moore
Ryo Chijiiwa



Joel Jefferson
Written by Joel Jefferson

Joel is one of the original founders of After college, he joined the USMC where he served as an (0302) Marine Infantry Officer. Joel is an avid outdoorsman and spends much of his free time in the mountains. Joel’s hobby is researching survival gear & weapons as well as prepping. Read his full interview here. Read more of Joel's articles.

12 thoughts on “DIY: Making An Activated Charcoal Filter”

  1. I think SHTF is nothing more than pure and simple marketing genius to get us all to spend all kinds of money on shit that we wouldn't otherwise buy. Sorry, no level of preparedness is going to save you from a looting mob of several hundred people intent on finding supplies. Most will be armed. How about Martial law? They won't ask you nicely. You'll just disappear. How about everyone else dies but you. then your supplies run out. Sure you can wander, forage, and such, but what kind of living is that…….3 months, thats all you need. if it lasts longer than 3 months, and you survive that long, you can make it from there, with the other people like you, that survived. if you don't get shot on site, because by then it will literally be every man for themselves. I do prepare, and I do look for improvements all the time. Articles like this one are most welcome, as I would much rather do it myself, know what i'm getting, than rely on a product from a company whose sole purpose is to profit from your fear.

    • There is a lot of truth in that. Better off finding some natural springs that you could utilize in a low population area. If the water is bad and you are truly thirsty or under a lot of pressure then I think people will just drink without waiting on the filter to run its course.

    • I think you should wake up to reality since you are totally clueless to the economic collapse coming, Fukushima has destroyed our Oceans, the Gulf oil spill destroyed the Ocean, GMO Crops is killing our food sources, Drought is killing of billions in crops, EPA is controlling farmers.. OMG WAKE UP fool.

  2. If you run it through that filter a couple of times it just gets better. Unfortunately most of my wood is pine, I hear hardwood is much better, but any charcoal is better than none. I like the idea of pre-making them.

  3. I used cedar so well see how it goes im having a little trouble with it it expands like its got yo much in it. I had to take some out . Im still adding water its getting better though judt tri as l a nd error i guess i bet it will work better the tommorrow im trying to clear up some brandy

  4. Home made filters using charcoal are fine but they need to be slow drip if the flow runs around the edge it is not filtered so you have essentially have undemined your filtration system.

    many cartridge systems have a hollow filter so the water is forced through the filter cartridge in a gravity system
    whatever is the container it the path that avoids your fitration medium. if you try to filter more water than it can handle.

    I found that if water out exceeds water in your good if your creating pressure even if it is gravity you have a chance
    to bypass your medium.and if your trying to filter out a dangerous pathagen or chemical your setting yourself up for self poisoning.

    I like the barrel picture above that would work very well just recall if you have ever had a fish tank the filter got moss
    mold so you need to be prepared to break it down and clean it on a schedual.

    Stainless steel is a better but a plastic drum with a valve out it would have to have a dacron polyesther material
    to prevent medium from coming out.

    I use a 1 gallon stainless bucket hung on the barrel spout let it drip and catch it in another container this is for drinking water.
    For bating and washing dishes a cloth to remove sediment treat it with bleach unless you have a reson to think there is a dangerous chemical like murcury and a thousand other man made chemicals
    We already know that local water systems cannot at this point remove pharma drugs like lithium and many others
    that is why counter top filters are so popular.

    We had all better pray we do not have a national or regional blackout certain systems have power backup if not
    some plants would go boom they require a startup and shutdown procedure or they self destruct or damage themselves to a point of dismatling and rebuilding and that would take as much just to build a new system.

    Certain areas would become a chemical soup or a petri dish of disease even rain water is not safe remember
    acid rain ? imagine toxic clouds fuming from fires or certain chemicals vaporise when exposed to the air or burn.
    hence the chemical clouds. rain falling through NOT GOOD.

    I only say this so people can be aware that rain water is not always safe I have seen on survival shows where they
    pronounce rain water as pure well it is not always so we live in the most industrialized country in the world,
    it is only the control of emmisions and scrubber systems that make our air and water useable.
    otherwise we would look like China.

  5. 7/15/16 Would whole charcoal brickets be suitable for this? Say 5-10 minute pre soak in 5 gal. pail? Wait till you have Coors light on tap at the kitchen sink. Also might want to think twice about watering the lawn & just wait for it to rain? ahy yi yi! Scott Solar Middleton,WI


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