Clean water is necessary for daily survival. Water makes up about 60 percent of our body weight; every tissue, cell and organ needs it to perform normally. Lack of clean water leads to dehydration, and within about three days, lack of water can lead to death. Depending upon our health, physical activities, sweat, body size and the environment, our body needs to intake about 15 cups of clean water daily to function. Also, we need clean water for daily for activities such as brushing our teeth, cooking, washing dishes and bodily hygiene. Clearly, learning how to craft a DIY water filter is a good idea.

DIY Water Filter: Water Filtration Systems

In most homes, cities and populated areas, we depend upon public water-treatment systems to provide us with a dependable supply of safe, clean water. But what happens when natural or man-made disasters occur and suddenly the public water systems cease to function, or they function improperly? This is occurring in Jackson, Mississippi, as I write this in the fall of 2022—180,000 residents are without clean water. The public water system has failed to deliver, and people are thirsty.

In the backcountry, away from a public safe-water system, we often depend upon the small water-filtration systems as found in individual survival kits or sold in backpack supply stores to obtain safe water from streams and lakes. These little filters work great for a short time to provide a few cups of clean water daily. But what about larger wilderness base camps, remote campgrounds or remote self-sufficient cabins where several people need clean water daily? They need a much larger, faster method of filtering water than the individual-sized filters can provide.

Many home-emergency programs and backcountry camps depend upon high-capacity (2 to 5 gallons) gravity-fed commercial water-filter systems or boiling water when using water from lakes, streams or roof runoffs. The commercial filtration systems can cost from $200 to over $1,000, and boiling up to 20 gallons of water daily can take a lot of time and effort.

Inexpensive DIY Water Filter Methods

Thanks to the experience of developing-nations missionary groups and disaster-relief efforts, there exists a do-it-yourself water-filtration system that’s inexpensive—under $100—requires easy-to-find parts and takes about 20 minutes to assemble using only a drill and three bits. Called by many the “two-bucket water filtration system,” one bucket sits atop another bucket. The top bucket receives the questionable water for filtration.

In the bottom of that bucket, a ceramic filter installs, attaching to the lid of the second (bottom) bucket with a hollow stem, permitting clean, filtered water to flow into the bottom bucket. The questionable water flows from the top bucket through the filter, making water potable. It then flows into the bottom bucket, covered with a lid. Clean water then flows out for use via a spigot. It’s simple, using gravity to do the legwork, but it’s effective.

To assemble your own two-bucket water-filtration system for home emergency preparedness supplies or use at your mountain cabin or afield, use the following guide:

Materials

• Two food-grade plastic 5-gallon buckets, available at building-supply stores
• Two food-grade 5-gallon screw-on lids, available at building-supply stores or leevalley.com (screw-on lids are easier to work with and cleaner when filtering water than snap-on lids)
• One water spigot with watertight washers
• One 4-inch ceramic water filter, available at justwater.me

The Heart Of The System

The gravity-flow water-filtration system is only as good as its filter. For this reason, I chose a ceramic water filter that has a proven track record of use by missionaries and disaster-relief teams: the Just Water 4-inch-by-4-inch ceramic filter. It’s made in the U.S. and has a 0.2-micron ceramic case that contains activated charcoal impregnated with silver. Its filtration of bacteria, viruses and other harmful matter is confirmed by an FDA-registered laboratory. Each filter kit (approximately $50) comes with washers and a wing nut for attaching the filter to a bucket, a water spigot with washers and a hex nut, a siphon tube, cleaning pad and a microfiber filter sock to help keep the filter pores open during use.

Tools

• An electric drill
• One 5/8-inch bit
• One 3/4-inch bit
• One 1/4-inch bit

Drilling The Holes

Precision is of utmost importance when drilling the holes in the buckets and lid, as they need to be located in the right place and as clean a cut as possible to assure that contaminated water stays in the top bucket and doesn’t leak into the clean water in the lower bucket.

1. Top bucket hole for filter: Turn the top bucket upside down on a firm support. Secure a 5/8-inch drill bit into an electric drill. Locate the exact center of the bottom of the bucket. Most buckets have a dibble at the center. Slowly drill a 5/8-inch hole through the bottom. Clean the edges of the hole.
2. Top bucket hole for vent: Turn the bucket on its side and drill a ¼-inch hole 1.5 inches below the top rim of the bucket. This is a vent hole. It will allow air to be pulled into the buckets as water is being drained out the buckets. A vacuum would be formed if the holes were not there, which would stop the filtering action, and you would not be able to drain the bottom bucket.
3. Bottom bucket lid hole for filter: Place the bottom bucket lid on a solid surface. Using a 5/8-inch drill bit, drill a hole through the center of the lid. Clean the edges of the hole.
4. Bottom bucket hole for spigot: Take the bottom bucket and place it upside down on a solid surface. Measure 2 inches from the bottom rim towards the top and mark this spot. Using a ¾-inch bit, slowly drill a hole in the bucket. Two inches is high enough for the spigot not to be in the way of the bucket sitting level on a counter or table.
5. Bottom bucket vent hole: Turn the bottom bucket on its side and drill a ¼-inch hole 1.5 inches below the top rim of the bucket. This is another vent hole to let the bottom bucket breathe so that a vacuum seal will not develop.

Installing The Filter

Handle the ceramic filter with clean hands. When moving the filter, always hold it by the base, not the ceramic shell. You can stress the ceramic shell and it can break or crack. If this happens, the filter is no longer filtering correctly. Bacteria can pass through the crack and into the lower bucket. Hold the filter by its base when tightening the wing nut.

Make sure the top bucket is clean and free of shavings from the two holes you drilled into it. Two washers come with the filter; place one on the filter stem. Insert the stem through the hole in the bottom of the top bucket and through the hole in the lid of the bottom bucket. Place the second washer on the exposed stem and attach the furnished wing nut. Turn the wing nut until finger tight; be careful not to overtighten.

Fill the bucket with water and check for leaks around the filter. It’s important that there not be any leaks around the filter stem, as that would allow contaminated water to enter into the clean water in the bottom bucket.

Mounting The Spigot

A plastic spigot, two washers and a hex nut come with the Just Water 4-by-4 filter kit. Make sure the bottom bucket is clean and no plastic shavings are inside. To install the spigot, place one of the washers on the spigot stem. Insert the stem into the ¾-inch hole you drilled into the bucket. Place the second washer onto the spigot stem on the inside of the bucket and screw on the hex nut until finger tight. Caution should be used to avoid overtightening the nut and crushing the washer, resulting in a leak. Place clean water into the bucket to check for leaks around the spigot.

Cleaning The Bucket

Before final assembly of the system, sanitize the bottom bucket—the bucket that will contain clean water—with a diluted, unscented bleach solution. Mix 1 teaspoon of bleach with 1 gallon of water and wipe down the inside and outside of the bucket. Let it stand for five minutes and then wipe it off with a dry paper towel. Run a little of the bleach solution through the spigot, then rinse with clean water.

Assembly & Use

To assemble the filter system, begin by slipping the siphon tube over the stem of the filter, located on the underside of the lid attached to the upper bucket, so that it will hang down into the bottom bucket. Next, simply screw on the top bucket, which has the bottom bucket lid attached, to the bottom bucket. Reach inside the top bucket and slip the filter sock over the ceramic filter and place a rubber band around it to hold it in place. The purpose of the sock is to filter out heavy particulates before they enter the filter, preserving the life of the filter between servicing.

Now the filter system is assembled and is ready to be used. Sit the two-bucket system on a sturdy table or counter and fill the top bucket with water from a questionable source. To prevent insects, leaves and so forth from entering the bucket, screw on the top lid. If the water to be filtered is not clear, it should be filtered through a large coffee filter or clean cotton cloth to keep the ceramic filter from getting clogged. For a constant safe-water supply, someone has to monitor the flow from the top bucket and add questionable water as needed.

Maintaining The Filter

To keep the system working properly, it’s necessary to keep the filter clean, and that is relatively easy. You will know when the filter needs cleaning as the amount of water being filtered will slow down and a brownish layer of sediment will appear on the ceramic filter. When cleaning the filter, the first rule is to never use soap. Use any type of slightly abrasive cloth (not metal) or a soft brush. Gently wipe the surface of the filter, then rinse with water. Ceramic elements may be cleaned 100 or more times. The microfiber sock can be cleaned at the same time just by rinsing with clean water, but do not use soap as it can damage the ceramic filter.

Once you begin to use the buckets, they should be cleaned at least once a month. Use filtered water when making the bleach cleaning solution. When used properly, a filter will last a year or more, and when unused, it has an unlimited shelf life.

When first put in use, the flow rate increases as the filter becomes saturated with water. It will take approximately two days for the flow rate of the filter to reach its maximum output of about 1 gallon per hour without a siphon tube. Using a siphon tube, the output can be up to 35 gallons per day.