Have you drank enough water today? If not, consider this your reminder to fill up that plastic-free water bottle. But first, let’s talk about how to purify water.
Globally, one in three people don’t have access to safe drinking water, and while you may be among the lucky folks who do, you never know when you’ll need to how to make clean water
Maybe you’ll be traveling to a developing country or going on an outdoor adventure. Or maybe you’re aware of tap water contaminants, like heavy metals. Even in the US, agricultural and industrial leaching into the water systems have been linked to more than 100,000 cancer cases.
Whatever your circumstance, sometimes, you just need the ABCs of water purification. So whether you need to know how to purify river water before tour big backpacking trip or just want to ensure clean drinking water on the daily, sip on this article as we dip our toes iinto 5 ways to make water safe for drinking.
Contents: 5 Methods Of Water Purification
- Boiling Jump to section
- Chemical Treatments Jump to section
- Filtration Jump to section
- Purification Jump to section
- Natural Materials Jump to section
Boiling
At its most basic, purifying water boils down to eliminating harmful bacteria (though true purification means getting rid of far more than that). What’s the most surefire way to kill bacteria?
Heat. There’s no more trusted method for how to purify water naturally than boiling. In fact, this method is actually promoted by the EPA as a way to disinfect water during emergency situations. Here’s what to do:
- If the water is cloudy, let all sediment settle and use a coffee filter or clean cloth to filter it out.
- Bring the water to a roaring boil for at least one minute, three minutes if you’re at altitudes above 5,000 feet.
- Let the water cool before storing it in clean containers.
- A pinch of salt can improve the taste.
While boiling will kill most disease-causing microorganisms—including viruses, protozoa, and pathogenic bacteria—it won’t remove or destroy other contaminants, like salts, heavy metals, and chemicals, and thus should only be used as a sole water purifying method in a pinch.
Chemical Treatments
Disinfecting with the use of chemicals is another emergency option, though because regular consumption of these chemicals can have negative effects of their own, we also suggest only using these water purification methods for temporary or emergency situations.
How To Purify Water With Bleach
Unscented, regular, non-expired household chlorine bleach can be applied to water that’s been filtered through a cloth or coffee filter. The label on the bleach should read either 6 or 8.25% sodium hypochlorite.
Using a dropper, add 8 drops of 6% bleach or 6 drops of 8.25% bleach to a gallon of water. If the water is cloudy, very cold, or colored, double the amount. Stir the solution and let it stand for 30 minutes. You should notice a slight chlorine odor. If not, repeat the dosage and let it stand for an additional 15 minutes.
If the chlorine taste is very strong, pour the gallon into another clean container and let it stand for a few hours before drinking.
Effervescent Aquatabs are another option that uses a bleach-alternative sodium dichloroisocyanurate to kills microorganisms that lead to typhoid, dysentery, cholera, and other water-borne diseases in 30 minutes.
How To Purify Water With Chlorine
If the idea of drinking bleach turns your stomach more than the giardia infection you risk by not, there are other somewhat less extreme methods for purifying river water. Chlorine is used by approximately 75% of municipal water systems use chlorine as their primary disinfectant—along with including 11 of the 15 members of the EU, some of which have the cleanest water in the world—and many don’t drink tap water for this reason (us included), that’s not to say you can’t safely use it in a piunch.
Keeping chlorine dioxide tablets in your emergency kit or with your camping gear can provide you with a shelf-stable and lightweight solution to guarantee you’ll have water free of bacteria, viruses, and cysts like cryptosporidium.
How To Purify Water With Iodine
Perhaps you have traumatic memories of this rust red liquid being painfully applied to scraped knees as a kid but we promise, it doesn’t sting when you dilute and swallow it. Add two iodine purification tablets (or an equivalent amount of drops) to one quart of water, wait 35 minutes, and you’ll be protected against bacteria and protozoan parasites like Giardia Lamblia.
Filtration
For a continuous, day-to-day use you’ll want something more along the lines of a water filter.
The term “water filter” has become nomenclature for anything that removes any degree of contaminant from drinking water, but in truth, water filtration refers to systems capable of removing a specific set of contaminants. Water filtration systems possess multimedia filters that remove bacteria, parasites, protozoa, and particulates, but not viruses. Some, such as Brita filters, can also reduce chlorine taste and odor.
Popular among hikers and cyclists, filtration systems like the MSR TrailShot Microfilter are small enough to fit in a pocket and allow you to drink directly from the water source or fill up bottles. They require squeezing or pumping to push water through an activated carbon filter.
Lifestraw, a Climate Neutral Certified brand and Certified B Corp, has both filtration and purification options. For every purchase, they also provide a year’s worth of safe water to a child in need.
Keep in mind that across all water filtration systems, the filters themselves require regular maintenance (called backflushing) to remove contaminant buildup, and eventual filter replacement after a system-specified amount of gallons or liters are filtered.
Purification
If you want to know how to purify water at home safely and easily, a water purification system might be the answer you’re looking for.
Some, like the world-famous Berkey, are gravity-fed and rely on filters (also called elements) to purify water and remove 200+ contaminants. They also offer a number of plastic-free water filter options. Other, less eco-friendly versions often rely on plastic filters and typically require electricity. Its ability to remove viruses and pathogenic bacteria is why it’s classified as a purification system, rather than just a filtration system.
Like filtration purification systems remove bacteria, parasites, protozoa, and particulates, but have the added bonus of filtering out viruses, lead, asbestos, benzene, and other heavy metals, making them the most comprehensive type of “water filter”.
A water purifier’s first step involves microfiltration.Here, the filter’s composition of different media types (often including a coconut shell carbon filter) forms micro-pores so small that viruses, bacteria, particulate matter, cysts, parasites, and other contaminants can’t pass through.
But modern life has introduced a range of other contaminants to contend with, too—316, by EPA estimates, like agricultural pollutants, volatile chemicals, pharmaceuticals, heavy metals and fluroride. The next step, absorption, uses the process of ion exchange to attract such contaminant molecules, bonding them to the filter and keeping them out of the reserve flow of drinking water.
Finally, adsorption creates an ionic barrier that harnesses viruses’ electrostatic charge and pulls them into the filter. It essentially works like chlorine or iodine, without the need for chemicals.
How to Purify Tap Water With Reverse Osmosis
More advanced systems use reverse osmosis (RO), a process that uses pressure to push water through a semipermeable membrane, removing up to 99.9% of total dissolved solids (TDS), including chemicals, VOCs, heavy metals, bacteria, viruses, and fluoride.
If you don’t like that your city uses fluoride to treat the water (which, by the way, has shown no demonstrable positive effects on dental health through drinking), a reverse osmosis water purification system is an alternative worth considering.
However, they have a higher price tag, require power, and have actually been considered by some to remove too many TDS, like essential minerals calcium, magnesium, potassium, and sodium—though one can, and arguably should, acquire these from a healthy, balanced diet.
One can also purchase remineralization powders and tinctures to compensate or, as a simple and much more affordable solution, eat more pink sea salt.
Another common criticism of the RO system is water waste, and it’s a valid one. For whatever amount is run through an RO water filter, only approximately half that is rendered as drinkable water. The rest is undrinkable “concentrate” or “reject” water that contains all the stuff filtered out. For every gallon filtered, half a gallon goes to waste.
However, that doesn’t necessarily need to be completely wasted. RO concentrate water may not be safe for drinking, but it is free of bacteria, viruses and has only dissolved impurities. This makes it safe for watering plants or your sustainable garden, doing dishes, laundry, and cleaning. If you use a countertop RO system as we do—which not only means you avoid a difficult under-sink install, but also puts you in total control of the waste tank—keep a tub or bucket near your filter to store your wastewater to reuse as you like.
Filter replacement waste is also another concern, but not one exclusive to RO systems. In fact, RO filters need to be replaced less often than many other filtration systems—anywhere from 6 months to 2 years, depending on filtration stage, use, and base quality of water. We have a four-stage RO system and only need to replace stages 1, 2, and 4 once a year and stage 3 once every 2 years.
How To Purify Tap Water With UV Light
Another high-tech option is UV purification. UV water sterilization works by adding safe, UV light to sterilize water-borne pathogens. Most systems destroy up to 99.99% of harmful microorganisms without requiring chemicals but do need electricity—or in the case of Katadyn Steripen portable UV purifiers, at least battery power.
These are most popular for on-the-go purposes, but with no water waste, required filter changes, or chemicals, UV water purification is a solid eco-friendly way to purify water at home, too.
Natural Materials
While you may not notice it, water is being filtered all the time. Trees, sand, and other natural elements work like a carbon filter to trap debris, and sometimes bacteria, and prevent it from passing through—hence the collective interest in knowing how to purify water naturally. In fact, you may have one of these natural materials in your backyard.
Used for hundreds—if not thousands—of years, there are many materials that have properties that can remove particles and contaminants:
- Plants constantly filter by adding oxygen and removing carbon dioxide. In some cases, they also remove toxins and heavy metals, which is why water hyacinth and water lettuce are often used in wastewater purification.
- Oysters can filter 60 gallons of water while they feed and are used in some areas of the world to purify water.
- Coconut has various layers of fiber that can trap toxins and particles, including parasites like giardia and cryptosporidium.
- Charcoal may take awhile, but the carbon it contains removes toxic particles down to 1 micron, including lead, sulfur oxide, and nitrogen oxide. Just make sure it’s hard, not soft, charcoal.
While there are many guides with step-by-step instructions for making a DIY natural water filter, for safest results we’d recommend opting for one of the tried and trusted methods first if you can, and always see a doctor after consuming any potentially-contaminated water.