Water Filtration Versus Purification

There are three main situations where you need water storage. We’ve talked about the first two on our blog already, and today we want to cover the third one.

  • Grab N Go: Have some small, portable water containers included as part of your Disaster Kits so you can grab them in case of an evacuation.
  • Bulk Storage at Home: In case of an emergency where your water supply is cut off for a short period of time, you should have at least a two week supply of drinkable water on hand. Choose water storage containers that fit your space and budget constraints.
  • Long Term Water Needs: Since you can’t store endless amounts of water, if there is a long term water shortage, you must find a source of water and have some means of ensuring that it is drinkable via filtration and/or purification.

We want to explain the difference between filtration and purification so that should you need to access water for a long term emergency, you will know how to properly treat your water. Depending on how contaminated your water is, a simple filter may be safe enough. But it is usually better to be on the safe side and fully purify all drinking water.

Water Filtration

Think of water filtration like a strainer. You have a filter with tiny holes in it which will block certain undesirable things from getting through. Any chunks of dirt, rocks, bugs, etc. will be filtered out. Most filters today will also do a good job at blocking protozoa (i.e. Cryptosporidium, Giardia) and bacteria (i.e. Salmonella, E. coli). However, viruses are so small that they will get through the holes in a regular filter. If you use a water “filter” it is a good idea to also purify the water once you have strained out the larger impurities. Here are some of the common water FILTERS you may be aware of:

Water Purification

Water purification makes water safe to drink but does not necessarily remove all undesirable elements from the water (large items such as dirt, rocks, etc.). Water can be purified by boiling it (for at least 3 minutes to kill everything), by using chemicals such as iodine or chlorine, by using UV, or by using special water purifiers that are rated to actually kill viruses (i.e. Enteric, Hepatitis A, Norovirus, Rotavirus). Here are a few products that only PURIFY your water:

Filtration/Purification Combos

If you prefer to have one product that will both filter and purify your water there are two great ones that we recommend. The Berkey Water Filter is very popular among our readers and it’s great for both every day use AND for emergency situations. You could also use a filter and then also use water purification tablets, chemicals or boil the water to make sure you get all the smaller impurities out.


  • swimkin

    I own a British Berkefeld gravity feed system with both the white ceramic and Flouride filters on it. We use it daily for our drinking water. Somewhere I read that I should purchase the black filters for long term use. Also I am moving to an area with a golf pond behind my home. I wanted to know if I ever needed to use the pond water if my filter would filter out all the lawn chemicals used for the grass nearby. Anyone know?? And if I should purchase the black filters for this system, too??

  • Jennifer

    You recommend boiling water for 3 minutes to purify it. Do you lengthen the time if you live at high altitude and your water boils at a lower temperature? If so, by how much?

  • For me, water purification is a lot more cleaner and safer rather than using filtration process.

    • emorra

      If you choose to rely on either chemical or solar purification without at least using a coarse pre-filter such as a coffee filter or bandana, you will at the very least find yourself drinking a lot of debris.

      Most water sources are turbid (muddy) or contain “bits” such as small sticks and bits of grass and even small organisms (e.g. algae), these neither look appetizing nor taste good.

      Most importantly they can interfere with purification such that you can’t be sure that the water is totally safe.

      So if you choose one method over another, be sure you know all the facts before you drink the resulting water 🙂

  •  Coffee filters can be used before purifying your water.  (Off subject) Coffee filters are also great for sprouting seeds and reusing frying oil.

    • emorra

      Great tips 🙂

  • Jennycroft

    I just saw a UV water purifier pen kit at Costco last week!  I was intrigued and it was reasonably priced, I think around $50 or $60 dollars?  I’d love to hear more about the pros/cons of these, they seem really cool!

    • A SteriPen would be a great option to use after you use a filter, if you are worried about completely purifying the water. It would not get out big chunks though so you’d probably want to filter it first.

  • Readers might be interested in a variety of free long term water procurement and treatment information including rainwater harvesting, additional treatment options, greywater use, and more.

  • Vocstink

    How long to boil to burn off VOC’s with BP’s lower than water, then when to stop boiling to prevent the VOC’s with BP’s higher than water from remixing in via the distilling tube?