Clean water solutions for low- and middle-income countries don’t have to be expensive, but they have to be available. The statistics are sad: 1.7 billion people use a drinking water source contaminated with feces, and more than 500,000 people die of waterborne disease each year, most of them younger than 5 years old.
Clean water straight from the tap is as good as it gets. But until everyone has gold-standard infrastructure, there are lower cost solutions available. Boiling water over a wood fire is one of the most widely used methods in low- and middle-income countries, but it is also a health hazard for those working in poorly ventilated kitchens. Cooking fires also exacerbate deforestation. Instead, we’ve rounded up ten low-cost technologies to treat water, and not one requires boiling. Most of these are for household use, but a few are for community-wide treatment.
Do you know of other methods? Please let us know in a comment below.
Clay, sawdust and a plastic bucket can make a water filter that catches dirt and disease-causing microbes. In the classic design, mix clay with a combustible material like sawdust or rice husks, give it a flower pot shape and fire it in a kiln. The sawdust or rice husks burn away, leaving tiny pores in the ceramic through which water filters.
Potters for Peace promotes an open source system called CT Filtron, distributed in Ghana, that treats water with silver-enhanced ceramic filtration. CT Filtron is one of 25 ceramic filters archived for comparison in our Solutions Library.
In this spin on the charcoal filter, a team of E4C members in Bangalore propose a filter made of locally available materials including charred bamboo, gravel and natural adsorbents. “The process we propose is indigenous, eco-friendly, low cost and entails minimum maintenance,” the team wrote in a message to E4C. They estimate that their filter can handle 30 liters of water per hour, and it would be affordable for average households in the region.
If cost is a bigger concern than time or convenience, the cheapest way to treat water is to leave it in a plastic bottle in the sunlight. Leave clear bottles in the sun for a few hours and UV radiation and heat kills the microbes that cause diarrhea and other waterborne illness. The Sodis (for solar disinfection) method was deployed in some parts of Haiti after the earthquake in 2010, and it is used in emergencies and impoverished regions worldwide.
“It is the combined effect of UV irradiation and high temperature that leads to antimicrobial action,” according to a paper published in 2020 in the journal ACS Catalysis.
Solar disinfection is one of the cheapest ways to kill microbes in water, but it is possible to make mistakes. Clouds, shade and the placement of the bottles and the murkiness of the water can change the amount of time needed to disinfect. To take solar disinfection to the next level and remove the guesswork, try WADI. WADI, by Helioz, is a device that measures solar radiation levels to indicate when the water is sterilized. Just look for the happy smiley face on WADI’s display.
Yet there may be room for competing designs in this category: we came across this prototype of a solar indicator at IEEE’s Global Humanitarian Technology Conference in Seattle, Washington (USA).
Not to be confused with solar sterilization or disinfection, solar distillation purifies even muddy, salty or otherwise undrinkable water through evaporation and condensation. The power of distillation to purify saltwater makes it unique among the treatment methods featured on this page.
A solar still can actually be a cheap and simple piece of shaped plastic or glass, or they can be more highly designed devices such as Henry Glogau’s award-winning portable solar distiller featured in the video above. “The portable design merges local resource production with community architecture, providing freshwater and a shaded gathering place,” according to the video’s description.
To work, the still places water contaminated with salt or other impurities in direct sunlight where it heats and evaporates. The water vapor is trapped and condenses into droplets that run off into a container. This simple process takes huge amounts of energy, which is why solar stills can make more sense than stills powered by other fuels.
For another take on the solar still, see the Eliodomestico terracota household still in our Solutions Library.
Bicycles in all their glorious versatility and simplicity are a favorite at E4C, and we were pleased to find a small but thriving supply of bicycle water filter videos, including this one by mechanical engineering students at the University of Maine. The Clean Water Team developed the bike-powered filter, and their project page describes the build, including a bill of materials.
For more bicycle action, see our list of ten things you can do with a bicycle.
The plastic bottle makes yet another appearance as a water treatment device, this time as a simple filter that can remove sediment and even disease-causing microbes. Simply cut the bottom from the bottle, fill it with layers of gravel, sand cloth and charcoal, filter the water through it and hope for the best.
Slow sand filtration has the advantage of working on an entire community’s water source, not just individual households. West Virginia University offers a technical brief on slow sand filtration systems, including a design summary.
A slow sand filtration system is a combination of several parts: water storage tanks, an aerator, pre-filters, sand filters, disinfection stages, and filtered water storage tanks. The number of filters and filter types that are used in a given slow sand filtration system will depend on the quality of the source water and will be different for each community.
Chlorine is one of the most versatile and effective clean water solutions in LMICs and everywhere else. Chlorine can work in a community water supply to kill microbes before it enters people’s jerry cans or home water supplies. And it keeps the water safe from new contaminations long after it is added.
Community-wide water treatment with chlorine is now possible using only water, salt, electricity and a portable device called WATA. The system converts a measure of salt and water into sodium hypochlorite (bleach) by the process of electrolysis, passing an electric current through the saline soluiton. Designed by the Antenna Foundation in Geneva, Switzerland, WATA produces enough chlorine in two hours to treat 2,500 liters of water. The product has been tested for more than 10 years, it is commercially available and comes in five sizes depending upon the quantity of active chlorine desired (from 0.5 liters to 60 liters).
The AguaClara Reach Full Scale Plant is a compact gravity-fed water treatment system that uses a five-step process to treat and filter water. The system adds a coagulant to the water to settle out sediment and other particles, then runs the water through a sand filter and adds chlorine before storing it.
This community treatment plant can serve 1,000 to 50,000 people.
Please see E4C’s Solutions Library for more clean water solutions suitable for communities in low- and middle-income countries. In our database you can view standardized information about hundreds of products and compare similar technologies side by side.
You need to stay hydrated, that’s for sure, but is the tap water in your home safe? It is considered generally safe if it comes from a public water system in the United States, such as one run and maintained by a municipality.
When drinking water leaves a treatment plant on its way to your house, it must meet strict safety standards. That doesn’t mean that your water is free of all contaminants, but that the levels of any contaminants supposedly do not pose serious health risks.
What it does not mean is that it’s going to taste good. Or comply with your doctor’s orders should you have a health issue with chlorine and or fluoride, present in most municipal water.
Having some method for the water you drink and cook with to pass through a quality water filter is the best way to be certain of great-tasting water without the high cost of having to haul bottled water into the house. And you do have multiple choices for how to do that.
Based on lots of research, testing, and tasting, here are my picks for the Best Inexpensive filtering pitcher, under-sink reverse osmosis, and countertop filtering systems.
The field is crowded with lots of choices, but for the money, I don’t think you can beat the highly improved ZeroWater, 20 Cup Water Filter Pitcher. That’s mostly because of its 5-stage filter, which will filter 40 gallons of water before it needs to be replaced—about every two months with typical use.
At a 20-cup capacity, this pitcher easily holds enough filtered drinking water for a family, provided it is filled regularly.
The pitcher is completely BPA-free; filters are quick and easy to change and don’t leave black flecks in your water. The filter promises to reduce chlorine taste and odor, copper, mercury, and cadmium.
If you’re serious about home water filtration, it won’t be long before you ditch the pitcher in favor of a reverse osmosis system, which is what we have in our home.
This is a fairly simple installation that goes in the cabinet under the sink, but it can get pricey if you call a water service or plumbing company and accept whatever product they’re selling that day.
A much cheaper way to do this promises fabulous results: Buy a high-quality system yourself and perform the installation if you have basic plumbing skills. Or once the system arrives, call a plumber to install it.
Either way, you’re going to come out as a winner if you go with my pick for the Best Inexpensive: APEC Top Tier 5-Stage Ultra Safe Reverse Osmosis Drinking Water Filter System. Remarkably, this system requires no electricity, working with gravity and water pressure to produce excellent drinking water.
For starters, it removes 99% of contaminants, including arsenic, chlorine, lead, fluoride, heavy metals, bacteria, virus and more—and that’s a very good start! Check it out. Plan on replacing filters approximately every 12 to 36 months.
If you prefer a more robust system that guarantees up to 6 gallons of purified water (depending on the model) available at all times (enough to take care of daily drinking and cooking needs for 4-6 people) consider Berkey Filters. All Berkey Filter systems are made in the USA and we really like that.
Big Berkey Countertop Water Filter System comes in sizes from 2.25 gallons to 6 gallons, with 2 Black Berkey Elements and 2 Fluoride Filters. Each purification element has a lifespan of 3,000 gallons; each Fluoride Filter can filter up to 1,000 gallons.
Berkey is big, and if you have space, it’s a great system because of its power to purify even seriously contaminated water. Berkey makes an impressive line of water filters, and this company really deserves your attention.
Berkey Water Filters are undoubtedly the runaway favorite of folks who are prepared for disasters. I don’t have room for a Berkey in my kitchen where we have a reverse osmosis system. But in the basement? As an additional source of pure water? In Vangie, our camper van? Oh yes!
Travel Berkey has a capacity of 1.5 gallons, and designed to be a great traveler
The system is just 18” tall and 7.5” in diameter.
Are you confused about the best and least expensive way to guarantee you’re drinking purified water that tastes good? Grab a calculator. Compare how much your household is spending on bottled water per day, week or month. Then multiply to get to an annual cost.
How does that number compare with the price of say a ZeroWater Filter Pitcher (consider both the purchase price and the cost of replacement filters)? How long would it take to recoup the cost of a better system, when you consider that you will stop buying bottled water?
Or if the idea of having only 10 cups of water available compared to a constant supply (under-sink reverse osmosis) or a super big amount sitting in a big shiny countertop container, crunch those numbers, too.
You may be pleasantly surprised by the results.
Updated and republished: Jul 25, 2023
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