Water Filter Basics

Storing clean, filtered water is essential when in the beginning stages of building up your emergency storage supplies. There are a variety of ways to make sure the water that you plan on drinking is safe. Boiling, distillation, reverse osmosis, deionization, chemical purification and filtration are the most common techniques. Today, we are going to specifically talk about how a water filter works and what options you have in regards to portable water filters.

How Does A Water Filter Work?

How Water Filters WorksMost water filters have tiny openings or a mesh that filters out the bigger particles, like dirt and sediment. Next, the water will pass through a polyester filter (mesh is a little smaller). This filters out clusters of bacteria. The most important  part of the water filtering process is when it passes through a chamber of beads that contain iodine. This will kill 99.3 percent of bacteria and viruses. The final step before it reaches you is having the water pass through a chamber of granulated active carbon (GAC). This improves the taste and smell of the water. It will also filter out any remaining parasites.

Many people already use water filters in their homes. Usually, they are attached to their faucets or used with a water pitcher. Typically, these water filters use some sort of carbon filter, micro porous filtration or a combination of the two to purify the water. Portable water filters like the Berkey Portable Water Filter use the same methods to clean water. Hikers, military personnel, survivalists and other people in harsh climates use portable water filters on the go. The filters are designed to remove and reduce toxic chemicals, heavy metals, volatile organic compounds, trihalomethanes, detergents, pesticides, herbicides, chlorides, pharmaceuticals, petroleum-based products, unpleasant tastes and odor, silt, sediment and chlorine. 1

Advantages of Portable Water Filters:

  • Allows for quick access to safe, purified drinking water whenever you find a water source
  • Removes debris from the water it is filtered
  • Portable and simple to use and maintain

There are also other types of portable water filter like the MSR Miniworks and the Katadyn Combi that contain ceramic filters. Keep in mind, that ceramic water filters, while designed for outdoor backpacking, hiking and military use, still need to be handled carefully. If dropped or damaged, the filter can get very small hairline cracks in it that will allow larger molecules to get through the filter and make it not safe to use.

What a Portable Ceramic Water Filter Can't Do:

  • Remove viruses from water sources such as Hepatitis A and Rota virus
  • Remove chemicals all chemicals from the water
  • Remove salt from the water

Take the first step towards preparing to be more self-reliant and add water filters to your storage! Whether it be for your next hiking trip or for a disaster, you can never be too careful when it comes to drinking safe, filtered water.


14 thoughts on “Water Filter Basics”

  • John

    Since potable water is so important for survival in long-term emergency situations, and since filter devices can break and wear out, it is a good idea to buy the maintenance kit and at least one extra set of replacement filters for the filter system you intend to use.

    As you indicated, mechanical filters (the simplest and most cost-effective solution) won't remove viruses. So you probably need to keep some of the water purification chemical products on hand, too. You use the chemical on the raw water, then use the filter -- if your filter has an activated charcoal filter, it will remove some of the unpalatable taste that chemical purifiers leave in the water. To make water that has been chemically treated taste better, you might keep on hand some powdered sports drink (e.g., GatorAde (r)) and dissolve enough in each container of water to mask the taste. The sports drink powder is also useful when you have an illness that causes dehydration -- the electrolytes in the drink make it more effective than plain water in staying hydrated.

    • TheReadyExpert
      TheReadyExpert April 2, 2009 at 7:42 am

      Great info. Having a maintenance kit for your water filter is a great idea. We also offer a replacement for the ceramic cartridge and if you can afford to, it is a good idea to keep one of those on hand as well. Each ceramic filter, will purify about 500 gallons of water depending on water clarity. Thank you!

  • Joe Kruger

    Great article. As you mention, one of the downside of a mechanical filter is that it won't remove viruses. I've heard of filters that incorporate UV light to kill viruses, but I can find very little information about it.

  • spoon

    8 drops of bleach per gallon of water also kills the bugs. Leave sit to evaporate the bleach for 30 minutes.

  • spoon

    These guys add a little more. Washington State Health Dept.

    Emergency Preparedness and Response
    Bad Weather
    Disease Outbreaks
    Emergency Telephone Numbers
    En Espanol
    Bomb Threats
    Calling 911
    Carbon Monoxide Safety
    Chemical Agents
    Cold Weather
    Children and Disasters
    Deaf and Hard of Hearing: Disaster tips
    Emergency Supplies
    Fires in the Home
    Floods: Cleaning a Basement
    Generator Use During a Power Outage
    Germs: Prevent Their Spread
    Hot Weather Safety
    Home Emergency Preparedness
    Landslides and Mudflows
    Medical Needs: Disaster Tips
    Medication Distribution During an Emergency
    Mobility Disabilities: Disaster Tips
    Out-of-Area Contacts
    Pandemic Flu
    Pets and Emergencies
    Pneumonic Plague
    Power Outages
    Psychological and Emotional Needs
    Sewage Spills: Cleaning Them Up
    Shelter In Place
    Turning Off the Utilities
    Vehicle Preparedness
    Viral Hemorrhagic Fevers
    Visual Disabilities: Disaster Tips
    Water Purification
    Water Sources
    Water Heaters (How to secure them)
    Get Ready
    Power Outages

    Purifying Water During an Emergency

    The treatments described below work only to remove bacteria or viruses from water. If you suspect the water is unsafe because of chemicals, oils, poisonous substances, sewage or other contaminants, do not drink the water. Don't drink water that is dark colored, has an odor or contains solid materials.
    Storing water safely

    The best source of drinking water during an emergency is water you have stored with your emergency supplies.

    Store one gallon of water per person per day--enough for at least three days.
    Store-bought, factory-sealed bottled water is best. Check for an expiration date and replace as needed.
    If you choose to fill your own water containers:
    Collect the water from a safe supply.
    Store water in thoroughly washed plastic containers such as soft drink bottles. You can also purchase food-grade plastic buckets or drums.
    Seal water containers tightly, label with date, and store in a cool, dark place.
    Replace water every six months.
    Never reuse a container that held toxic substances such as pesticides, chemicals or oil.

    Purifying by boiling

    If your tap water is unsafe, boiling is the best method to kill disease-causing organisms.

    If tap water is unavailable, the following may be considered as potential water sources. Water taken from these sources should be boiled before drinking.

    Rivers and streams
    Natural springs

    Caution: Many chemical pollutants will not be removed by boiling.

    Cloudy water should be filtered before boiling. Filter cloudy water using coffee filters, paper towels, cheesecloth or a cotton plug in a funnel.

    Bring the water to a rolling boil for at least one full minute.
    Let the water cool before drinking.
    Add two drops of household bleach per gallon to maintain water quality while in storage.

    Purifying by adding liquid chlorine bleach

    Treat water by adding liquid household bleach, such as Clorox or Purex.
    Household bleach is typically between 5.25 percent and 8.25 percent chlorine. Read the label.
    Avoid using bleaches that contain perfumes, dyes and other additives. Be sure to read the label.
    Cloudy water should be filtered before adding bleach.
    Place the water in a clean container. Add the amount of bleach according to the table below.
    Mix thoroughly and let stand for at least 60 minutes before drinking.

    Treating water with household bleach containing 5.25-8.25 percent chlorine
    Volume of Water to be Treated Bleach Solution to Add
    1 quart/1 liter 5 drops
    1/2 gallon/2 quarts/2 liters 10 drops
    1 gallon 1/4 teaspoon
    5 gallons 1 teaspoon
    10 gallons 2 teaspoons

    Caution: Bleach will not kill some disease-causing organisms commonly found in surface water. Bleach will not remove chemical pollutants.

    DOH Pub 821-031
    Revised - July 2013

  • wilson

    carbon block filters can remove many of the things ceramic filters can't. check Multipure Brand.

  • Sandra A

    There is a bad mistake in the article above about bleach with the water (at least on my screen it appears to say to put "4" TSP of bleach to a gallon of water. I believe they meant 1/4 (one fourth) teaspoon. 4 tsp of bleach in 1 gallon of water is NOT safe.. The article goes on to say "1" Teaspoon for 5 gallons. Please take note.

    Also note there is a safer alternative to bleach on the market: Water Preserver. Look into it.

    The item I have is the Aqua Pail. You can look it up on Youtube.

  • Bubba

    A company called lifesaver invented a filter that removes particles down to 15 nanometers, which is smaller than viruses. It is used in disaster areas. Although expensive, one filter can treat 4,000 liters of water. I have one in my closet and don't have to store water. Check it out.

  • Doc

    Sawyer also makes filters that remove even viruses and are good for 1 million gallons. The best I have found.

  • Franke

    I own a Sawyer 4-liter dual bag portable ultra purification system. It's a bag gravity system so doesn’t require any pumping, and purifies a gallon of water very quickly. It uses a .02 Micron absolute hollow fiber membrane purifier, and
    removes 99.997% of Viruses, 99.99999% Bacteria, and 99.9999% Protozoa/Cysts. It's light, packs small and the filter is rated for one million gallons. I have it as part of my bug out kit. Like most purifiers, it doesn't remove chemicals though. Some will find it a bit expensive, but since you don't have to replace the filter, the cost balances out. They have typical 0.2 micron units which cost less.

  • Anthony Dean Westfall

    The Info page says 120 gallons treated and now you say 500. which is it?

    • Randy Fedell

      Can you use the water in a swimming pool?

      • roberto buerno

        Use swim pool water ?
        Even if you kept the chemical levels up to date (chlorine type, ph additives etc), remember... the birds,bees etc. pee& poop while flying, much less dieing in your pool. BUT... it is probably your easiest & safest to filter in an emergency for a steady consumption.

  • bob

    Know your local water!
    within 25 miles of my location is one water body that runs thru a bed of arsenic and another thru salt. getting good water from either is tough unless you know what you are doing

Leave a Reply