Water is used for a lot of things, from washing the dishes to preparing food and drinks. Fortunately, there are many techniques available to lower contamination of water and make it safe for consumption.
Some of the most popular methods include filtration, distillation and preconditioning. However, chemical treatments like chlorine are controversial because they may create dangerous by-products such as trihalomethanes and haloacetic acids.
1. Gravity Filters
The most basic gravity water filter relies on the universal law of gravity to purify your water. When you pour water into the upper reservoir, it’s pushed by gravity into the lower one through a filter.
Most gravity filters use a simple, black ceramic filter that removes bacteria and protozoa like Giardia and Salmonella. Some models also use a black carbon filter that reduces other contaminants. They typically have a large capacity and can be used for camping or during international travel.
If you’re looking for a portable, lightweight gravity water filter, the Katadyn BeFree Gravity Filter is an excellent choice. It’s designed to be used on the go and comes with a collapsible flask that fits well in backpacks or coat pockets. Its BPA, BPS and BPF Free plastic is durable and sturdy, and the transparent design allows you to see how much water is left at a glance.
When you’re using a gravity filter, it’s important to regularly clean the dirty bag, hose and filters. Make sure to drain the system and clean all of the components before storing them until you’re ready to use it again. Be sure to store the components in a cool, dry place away from direct sunlight and extreme heat or cold. It’s also a good idea to change the filter once it reaches the end of its lifespan, which can range from a few months to a couple years depending on the type of filter you have.
2. Reverse Osmosis
Reverse osmosis uses membrane-technology to remove many types of particles from water. When pressure is applied to a solution with higher concentration of solute on one side and pure solvent on the other, the solute will naturally migrate towards the higher concentration until the difference in Gibbs free energy of the system equalizes. The process of applying external force to reverse the natural flow of solute is called reverse osmosis.
Reverse Osmosis filters usually use a series of pre-filters, a membrane, and carbon post-filter to filter out a wide variety of aesthetic contaminants, including heavy metals like lead or chlorine that affect the taste of your water. Some systems also include a final remineralization treatment before dispensing the filtered water to add back minerals that were removed during the filtration process. Our pick from iSpring includes this extra step to give the water a more pleasant taste profile.
Most RO systems require some degree of plumbing, with under-sink models installing on your home’s cold-water line using saddle valves and a drain line to expel wastewater. Countertop units typically connect to your faucet through a diverter valve. The first stage in most reverse osmosis systems is a polypropylene spun sediment filter that removes visible particulate to protect the membrane from clogging.
From there, the water goes through a semi-permeable membrane that separates ions with opposite charges. The membrane also removes organic materials and most chemicals that are dissolved in the water. The filtered water then goes to a pressurized storage tank and through a carbon post-filter to remove any remaining aesthetic tastes or odors — think of it as the “polishing stage” for your water.
3. Faucet Mount
If you’re worried about pollutants dissolving in your water supply on the way from the municipal treatment plant to your home, or just want to add another layer of protection from contaminants, a faucet-mounted filter is a great option. These filters treat water before it leaves your sink and usually come with a filtration cartridge that is NSF-certified to reduce most or all of the chemicals, heavy metals, and other impurities that can discolor your drinking water and leave bad tastes.
Most of these filters offer a convenient, do-it-yourself installation. First, you’ll need to install a blocking crossmember at the height of your faucet. Modify the framing if necessary to accommodate this block, then screw it to the two studs on either side of your faucet. Use a torpedo level and the manufacturer’s instructions to ensure your faucet is set up at the proper height above the surface of the counter.
Next, remove your valve handles and spout escutcheon to reveal the mounting nuts. These will be a different size than the washers and bolts that hold your faucet, so you’ll need to use a wrench or pliers to loosen and remove them. Once you have the handle and spout removed, apply a thin bead of plumber’s putty or silicone caulk to the base of your faucet. Wipe away any excess before installing your new filter. Most faucet-mounted systems also allow you to switch between filtered and unfiltered water with a lever or button. This provides versatility and extends the life of your filter cartridge by limiting its exposure to hot water.
4. On-the-Go
Whether you’re a backpacker traveling in unfamiliar territory or a disaster-prone region, bringing a water purifier is almost always a good idea. Viruses, protozoa and bacteria in untreated water are common travel concerns, and they can be more dangerous than just getting a stomach bug from bad food or even a mosquito bite.
Most water purifiers rely on some form of physical filter to remove these microbes from the water, and they’ll need to be replaced at regular intervals to keep them working properly. This frequency will depend on how much you use the purifier and how dirty your water is. It’s a good idea to get a few extra filters so you can change them out quickly if you expect to need to use your device frequently on the go.
There are many different types of portable water purifiers on the market, and it’s important to understand what each one does best before deciding which to purchase. Look for a purifier that explicitly mentions how many contaminants it can remove, including any viruses. Most filter types can handle bacteria and cysts, but viruses require a more sophisticated system to eliminate.
Some portable water purifiers work with your existing bottle or container, and others are standalone devices like the Steripen Ultra that looks a bit like a pen. To use it, simply dunk one end into your water and wait until the light on the body of the device indicates it’s been cleaned thoroughly enough to drink.