f you have been considering the option of buying a water filter for your home, then you are in the right place. This article will explain to you some of the factors that you need to consider before you buy this very important equipment for your home. There are a number of reasons why one would need a water filter for their home. If a family member has a compromised immune system, then a water filter would be a very important addition to prevent them from getting sick frequently.

“Water, water, everywhere, Nor any drop to drink.” 
— Samuel Taylor Coleridge

The first requirement for any community is a secure and clean supply of drinking water. This explains why early civilizations were founded along the banks of major rivers such as the Nile, Indus, Yangtze, Tigris, and Euphrates.

While these major rivers provided the necessary quantity of water, the quality was often endangered by contamination from the civilization itself, which made necessary a system carry away waste and eventually, the filtration of the water supply.

Filtration is defined as “a mechanical or physical operation, which is used for the separation of solids from liquids by interposing a medium through which only the fluid can pass. Oversize solids in the fluid are retained, but the separation is not complete; solids will be contaminated with some fluid and filtrate will contain fine particles (depending on the pore size and filter thickness.” (Source: “Fibers and Fabric for Filtration,” Silajit Naskar). In the context of providing safe drinking water, the solids to be removed are turbidity-causing suspended sediment and microbes (especially pathogens).

The permeability (rate at which water can pass through, typically measured in cm/sec) of the filter medium is proportional to its pore size with total travel time being a function of its thickness. The actual movement through the filter medium is either by gravity or applied pressure/vacuum. This applies a head on the liquid which forces it through the filter media.

Water filtration systems remove the impurities that make water unfit for human consumption. They do so by means of physical barriers, chemical processes, or biological action. Though the ancient Greeks and Egyptians understood basic water treatment methods, such as bag filters to sieve water and the addition of alum to allow the removal of impurities by coagulation, the first water filter systems for domestic use were built during the Enlightenment era, with the first public filtration and treatment system built in Scotland in the 19th century. Made from alternating layers of wool charcoal, these early filtration systems were eventually replaced by the late 1800s by large-scale sand filters that serviced entire cities.

But now that basic water filtration is a mature technology that has been adopted worldwide, a new challenge has presented itself to a world with almost 8 billion people (half of whom now live in cities): the need to desalinate large quantities of seawater in an efficient and cost-effective manner. Not only are natural sources of freshwater stressed from excessive demand, but extreme weather and drought threaten the sources of freshwater for entire regions of the globe. To meet these new demands, new filtration technology utilizing graphene and other exotic materials are being developed and deployed.

These new filters operate at the atomic level, with the carbon rings forming the sheets of graphene (which itself can theoretically be one atom thick) presenting holes large enough to let water molecules pass but retain impurities such as sodium chloride molecules. Such membranes, reinforced by walls of epoxy resin, have been shown to effectively remove salt from saltwater. As a result, the world could have access to vast amounts of freshwater directly from the world oceans—enough water to quench the thirst of billions of people and provide enough irrigation water to turn the planet green. Our current scarcity of drinking water could become a thing of the past.

NATURAL WATER FILTRATION
The world is not short of water. The world is short of potable water. Water filtration systems address this shortage. The most basic materials used as water filtration media are some of the most common: sand and diatomaceous earth. The table on the following page summarizes the characteristics of each type of filter.

Simple operation, high reliability, ease of construction, and low operating costs are the hallmarks of slow sand filters. These characteristics make them the most prevalent system for small and mid-sized rural communities and were the earliest method developed for large-scale water filtration. Because of their simplicity of operation, only the most basic skills are required of its operators. They effectively and efficiently remove both sediment and turbidity via physical screening and pathogens with biological and chemical processes.

This is accomplished by a single pass through operation that takes in contaminated water at the top and yields potable water for extraction at the bottom. Unless the intake water is suffering from an excessive amount of algae contamination or extremely high degrees of turbidity, a sand filter can by itself perform the necessary purification operations without the need for pre-treatment. The World Health Organization has designated slow sand filtration as the least expensive, simplest, and most cost-effective means of providing potable water.

The simplicity of the slow sand filter comes from its design. Contaminated water enters at the top through the upper surface of the sand layer. Both the physical screening and biological treatment occurs at this location. The first step is removal of sediments by the sand physically acting as a sieve, its pores allowing water to pass through, while being too small to allow further migration of sediment and turbidity particles. But of greater importance is the natural anti-pathogen treatment it provides.

This is based on the ability of bacteria to attack and consume these disease germs. The top layer of the sand quickly becomes biologically active with the development of a scummy layer called schmutzdecke, German for “dirty skin.” The microbial community attaches itself to sand particles exposed at the top surface of the sand layer within a few days of operation. The established microbes are mostly predatory bacteria that attack and consume water-borne disease pathogens. This biological surface film must be manually or mechanically scraped off at regular intervals to prevent clogging. And in general, a slow sand filter must have a relatively large surface area to manage large quantities of water at slow flow rates.

A rapid sand filter differs from a slow sand filter in several aspects, not just filtration speed and flow rate. Essentially, rapid sand filtration is a physical process as opposed to the biological process utilized by slow sand filters. Rapid sand filters either use gravity drainage to move water through the system or apply high pressure to the water flows. Since a rapid sand filter is primarily physical in nature, some biological pre-treatment and post-treatment is typically required. These include coagulation combined with flocculation and the addition of chlorine to ensure disinfection. Also, unlike the slow sand filter, the construction and operation of a rapid sand filter is both complicated and relatively expensive. However, rapid sand filters are the appropriate choice for developed nations and communities with sufficient resources to build them and skilled engineering staff to operate them.

The primary rapid sand filter unit is typically a cylindrical chamber or a square tank made from reinforced concrete. The chamber is filled with alternating layers of sand and gravel to a height of about 6 feet. The bottom is lined with a series of perforated pipes that collect and extract the purified water. Rapid gravity filters have open tops, are simpler to construct and operate, and don’t need large powerful pumps, but they have lower flow rates. Rapid pressure filters have completely enclosed tops, are more complicated, utilize large pump systems, and can handle large flow rates—making them more suitable for servicing larger communities. In either case, filtration results from the clogging of sand pores with larger particles of sediment while smaller particles physically cling to sand grains due to Van der Walls forces. The addition of coagulants or flocculants to the water in feed promotes increased adhesion and clumping of particles, increasing removal efficiency.

Like the slow sand filter, clogging of a rapid sand filter can occur over time. However, instead of mechanical removal, the rapid sand filter is cleaned by reversing the water flow under high pressure to cause back-washing of the accumulated material out of the top of the filter unit. The reverse flooding of the chamber causes the sand particles to be suspended, increasing the void volume between the sand grains. This allows enough room for the lifting and removal of sediment particles out of the sand media. To assist this process, high-pressure air is often injected as well. The large quantities of sludge produced by the backwashing process require their own management and disposal operation.

The diatomaceous earth filter differs from other natural filters primarily in the material used as the filter media. Diatomaceous earth isn’t soil at all. Instead, it consists of powdered media made up of almost pure silica. This silica is manufactured from diatoms, the hard-shell skeletons of freshwater single-celled algae. Primarily used for small-scale applications where water purification standards are very high, such as public and private swimming pools, these tend to be more expensive than standard sand filters. Their effectiveness is a result of the microscopic pores found in the hard-shell bodies of the algae. These provide very effective mechanisms for trapping impurities.

There are three primary types of diatomaceous earth filters: horizontal plate, vacuum, and pressure. In vacuum filters, negative pressure is applied to force the water through the filter medium. This allows for a configuration with a large contact surface area in proportion to the filter chamber’s overall volume. This greater surface area allows for higher flow rates. Pressure filters, which use applied pressure to deliver water to the filter chamber, are more limited in their size and are used for smaller-scale applications. Horizontal plate filters are a kind of pressure filter with the filter medium arranged in parallel with horizontal filter plates. After backwashing with compressed air through the filter plates, the residue is trapped on the horizontal plates, allowing for easy removal.

MAN-MADE FABRICS, MEMBRANE, GRAPHENE, AND OTHER WONDER MATERIALS
Natural earth isn’t the only type of filtration material. Man-made fabrics have been used to filter and sieve water for millennia. Traditional cloth filters are inexpensive, low-tech, and relatively easy to use. While not 100% effective, this simple method can greatly reduce floating parasites, pathogen counts, and turbidity in drinking water taken directly from river and groundwater well sources. Studies have shown that even a simple wrapped cloth can greatly reduce the incidence of cholera in third-world villages that lack more sophisticated water purification systems.

Similar in principle but far more advanced in the application is the process of reverse osmosis filtration. “Reverse Osmosis (RO) is a water treatment process that removes contaminants from water by using pressure to force water molecules through a semipermeable membrane. During this process, the contaminants are filtered out and flushed away, leaving clean, delicious drinking water” (ESP Water Products).

Reverse osmosis achieves this purification by means of a semi-permeable membrane that traps and removes particles as small as individual ions and molecules. To overcome inherent osmotic pressure, high pressure is applied to the water that forces the liquid across and through the membrane, leaving contaminant particles and molecules behind. This applied pressure reverses the natural direction of flow, thus the description of the process as reverse osmosis. While this may seem similar to pressure filtration, there are significant differences between the two processes, not the least of which is the filter medium. Reverse osmosis involves both straining (exclusion of particles based on their size compared to the open pores) and diffusion. As such, reverse osmosis has found its most widespread use in the area of seawater desalination since it can remove individual salt molecules as well as sediment and microbes.

Most drinking water purification systems, whether individual home systems or giant community systems such as the facility used by Orange County, CA, utilize reverse osmosis. Some of these systems involve multiple steps to accomplish the conversion of seawater into potable water: an initial sediment filter (or two filters in sequence with progressively smaller pore sizes) to trap large particles, activated carbon to trap organic chemicals (such as chlorine), and finally the reverse osmosis membrane itself. Advanced systems may employ post-membrane carbon filtration and an ultraviolet sterilization lamp to kill any remaining microbes.

Membrane pore sizes can vary depending on the type of contaminants to be removed and the type of filter material. The pore size range is from 0.1 to 5,000 nm (4 x 10−9 to 2 x 10−4 inches). This pore size range is broken down into five size categories: particle, microfiltration, ultrafiltration, nanofiltration, and hyperfiltration. Particle filtration removes particles of 3.9 x 10−5 inches or larger. Microfiltration removes particles of 1.9685 x 10−6 inches or larger. Ultrafiltration removes particles of roughly 1.1811 x 10−7 inches or larger. Nanofiltration removes particles of 3.937 x 10−8 inches or larger. Reverse osmosis is performed by membranes with pore sizes in the hyperfiltration range, removing particles larger than 3.937 x 10−9 inches.

The membranes used by reverse osmosis units are typically semi-permeable, thin-filmed composites. The membrane itself is a thin (less than 7.874 x 10−6 inches thick) polyamide layer placed on top of a porous polyether-sulfone or polysulfone layer of about 0.0019685 inches thick. These are, in turn, fixed to a non-woven fabric substrate that provides physical strength and support. Most of the work of desalination is done by the polyamide layer which has an affinity for water molecules while it rejects dissolved salt ions.

Going from ancient times to the Space Age gives us man-made filtration materials such as graphene. Graphene is a version of carbon that forms a two-dimensional lattice of carbon atoms arranged in a repeating hexagon pattern. Often touted as the strongest material on earth, it is also being researched as the ultimate water filtration medium. The openings of these hexagons create pores that are sized to remove not just microbes and soil particles, but also individual molecules. Its applications are not limited to water cleanup and desalination. It is also applicable to a wide range of industrial processes such as protein separation, wastewater treatment, and drug and pharmaceutical production.

Graphene is also the world’s strongest material, at least ten times stronger than steel, but that’s the least of its attributes. Its molecular structure allows it to act as a sieve small enough to cheaply and effectively remove salts from seawater. At first, graphene-oxide membranes were shown to be able to remove larger salts from seawater. Recent advances have shown its ability to remove the smaller salts that make up the bulk of seawater contaminants. Researchers have, in effect, shown that they can create membranes of uniform pore size right down to the atomic scale.

This allows for greatly reduced costs and energy requirements for desalination. More than half of the battle in desalination is applying the pore pressure necessary to push water through, while salt is trapped and accumulates near pore openings. When this advancement is far enough along to be scalable, a low-cost desalination method may become available.

Another approach is to embed graphene in bacteria-produced cellulose. The resultant product is a bi-layered biofoam. It has the ability to absorb light and, as it heats up, freshwater is evaporated. The biofoam consists of two layers of nanocellulose, both of which are created by bacterial action. The top layer is embedded with graphene oxide which is heated by the sun, while the bottom layer has a sponge-like consistency that pulls water up into the biofoam. When the water comes into contact with the upper graphene embedded biofoam, it evaporates and can easily be recovered as freshwater from the accumulated condensate. Both graphene oxide and the biofoam are cheap to produce. This allows mass production of tons of material at a time, making the approach highly scalable.

Another approach emphasizes ease of manufacture. It involves a spray-on, graphene-based coating applied to desalination membranes. The resultant product is durable and sturdy, capable of surviving even harsh operating environments. The membrane filter is able to function at high flow rates, is self-repairing, and has a long operational lifetime as it filters out salts and pollutants to generate clean drinking water without being subject to bio-fouling.

The hybrid membrane is created by simple spray-on applications that coat a mixture of graphene oxide and few-layered graphene onto the surface of a polysulfone membrane. The polysulfone has had its molecular structure modified by polyvinyl alcohol and serves as the structural substrate of the membrane. This structural support strengthens the membrane, allowing it to withstand high pressure and exposure to chlorine. It can easily remove up to 85% of salts (making the water suitable for agricultural applications) and up to 95% of chemicals such as industrial dyes.

MAJOR INDUSTRY SUPPLIERS

Dow Water & Process Solutions produces a family of reverse osmosis membrane filters capable of purifying different degrees of contaminated, brackish, and saline water. The company’s Dow Filmtec Brackish Water RO Elements come in various sizes for different applications. The 8-inch-diameter model treats difficult industrial water, enabling lower energy usage and reduced costs. The models sized 4 inches and smaller are designed to handle light industrial brackish water and commercial brackish water respectively. Similarly, the Dow Filmtec Seawater RO Elements comes in differing sizes with the 8-inch-diameter model featuring high active membrane areas with low net driving pressure. Greater flow rates are achieved with the 4-inch diameter and smaller models.

Evoqua Water Technologies provides a wide range of water and wastewater treatment products and materials. These include cross-flow, micro-sand filtration systems, and pressure filter systems, as well as membrane filters for reverse osmosis and ultrafiltration.

Pentair Water Filtration Division produces 3-stage (GRO-350B), 4-stage (GRO-475B & GRO-475M), and 5-stage (GRO-575B & GRO-575M) reverse osmosis systems. The filtration units can remove lead, volatile organic compounds, chlorine, biological contaminants that cause bad taste and odor, cysts such as cryptosporidium, and discoloring turbidity.

Senior Water America emphasizes the production of the membranes themselves. These are hollow-fiber membranes made from Polyvinylidene Fluoride (PVDF) using the thermally induced phase separation (TIPS) method of manufacture. Using their own proprietary designs and configurations, they manufacture membrane modules that serve as direct retrofits. They require no additional hardware and are essentially plug-and-play units easily inserted into existing filter systems.

The delivery of clean water through municipal water supply systems to our homes is one of the hallmarks of modern civilization. Modern water supply systems test and treat water to ensure it’s safe for all of our needs — drinking, cooking, cleaning, and more.

You want to be sure that the water we use is as pure as possible, and a practical way to ensure that is to add a water filtration system to your home, whether it is a whole house water filter or a water filter located on the water line in your kitchen sink or another water source.

Are you concerned about the water in your area? Check out this handy resource from the EPA that provides information on safe drinking water throughout the United States.

The benefits of a home water filtration system

Whether your water comes from city water or well-based water systems, you want to ensure that it’s safe for your family. There are many opportunities for contaminants to enter your water, and even if your water is free of contaminants, high levels of minerals can affect the taste of your tap water or make the operation of your dishwasher or clothes washer less efficient.

The best way to tackle these issues is to filter your water in your home, at the point where you’ll use it. Here are some of the benefits you’ll enjoy by installing a filtration system.

Enjoy safe drinking water all the time

The consequences of having unsafe drinking water can be dire. Pollutants like heavy metals can have profound health consequences at worst, or at best make your water unpalatable. While the vast majority of municipal water systems in the United States do an excellent job of treating our water and ensuring water quality, there is always the danger of system failures, so it’s best to be safe. If you filter your water with an effective home water filtration system you’re making a smart investment in the health of your family.

Save money

If you’re buying bottled water for your family to use at home the costs can add up quickly. For the average family drinking 2-3 bottles of water a day, annual costs can easily exceed $500. That’s money can be recouped in a timely fashion after you install a water filtration system in your home. And there’s another drawback to bottled water…

Help preserve our environment

You’re probably familiar with stories and images of the increasing costs to the environment of our society’s heavy use of plastic, and plastic bottles are a big part of the plastic waste stream. And even if you’re conscientious about disposing of plastic bottles, there’s no guarantee that you’re used plastic bottles will end up being recycled. Eliminating plastic bottles from your home’s waste stream can play a part in correcting this problem.

Reduce potential plumbing issues

Minerals, heavy metals, and chemicals in your water can cause corrosion and damage to your pipes and water-using appliances. By eliminating these potentially damaging factors at the source you can extend the life of your pipes, hot-water heaters, and other home appliances.

Prevent skin irritation

Individuals with sensitive skin or who experience skin irritations and conditions such as eczema or psoriasis can suffer from exposure to chemicals in water such as chlorine. A water filtration system in your home can go a long way towards alleviating these problems.

And even if you don’t suffer from these conditions, there’s nothing like the feeling of pure, clean water when you’re taking a shower or enjoying a tub!

Save on soap and enjoy cleaner clothes

Water that has a high concentration of minerals can diminish the effectiveness of soap. With the addition of a water filtration system, you’ll find that appliances like your clothes washer and dishwasher will clean more effectively. Clothes and dishes will be cleaner and your appliances won’t suffer from the buildup of mineral deposits.

Reduces limescale and other mineral deposits

If you’ve ever looked at the bottom of an old tea kettle, you may have noticed white, chalky deposits on the bottom. That’s limescale, the buildup of minerals from lime and other minerals in your water. In addition to being unattractive, limescale can build up in pipes and appliances, and it often makes your water taste unpleasant.

A quality whole-home water filtration system will alleviate many of the issues associated with limescale, and give you better tasting water as well.

Improve the taste of your drinking water

Water is one of the best fluids for your body, and adding more water to your diet can have real benefits for your overall health. So why not enjoy the best tasting water? With a whole house water filter in your home, you’ll enjoy the clean, crisp taste of pure water, every time you open your tap.

Understanding the different types of water filtration systems

Several different methods are commonly employed for water filtration in the home. Depending on your particular situation, the right one for your situation can vary. Let’s take a look at the science behind each of the most popular filtration technologies.

Reverse osmosis water filter systems

This is the gold standard for home water filter systems. These systems use air pressure to force water through a semi-permeable membrane. Properly installed, these systems can handle a large quantity of filtered water and eliminate almost all contaminants. Reverse osmosis systems are designed to operate as a whole house water filter. They’re placed in a central location and provide the entire home with filtered water.

Cation exchange water filter systems

These systems are known by other names, usually water softeners or exchange systems. They’re designed as whole-home systems, so all the water in your home will receive the benefits of employing one of these systems. The system works by creating positively charged ions that attract the negatively charged ions of earth metals like barium, calcium, and magnesium, minerals that can cause your water to taste bad and negatively impact your health.

Activated carbon

Activated carbon systems are relatively inexpensive and quite common. Activated carbon systems are usually located at the point of delivery, that is, before an individual faucet, such as in your kitchen. Your water supply flows through an activated carbon filter located in line with the faucet and the filter removes chemicals, parasites, or heavy metals present in the water.

Activated carbon filtration systems are inexpensive and easy to install, but the carbon filter in the system will need to be replaced regularly, and they don’t cover the entire home, just the faucet you’ve installed them in line with.

At our services, we offer a variety of different water filtration from respected manufacturers. Get in touch with us to find out what your options are.

Tips for installing a whole house filtration system

If you’ve decided that you’d like to tackle a house water filter installation, here are some useful tips for how to proceed with the job.

Be sure the whole house water filter you’ve selected is a good match for your home

Different house water filtration systems have different requirements for fittings and space required. It’s important that you carefully check the requirements of the system before you purchase a whole house filter system. If you’re in doubt, consult with a professional before undertaking the project.

Be sure your water pressure is correct

Did you know that your water pressure can be too high? Whole house water filters are built to operate within a specific range of water pressures, and if the water pressure is too high, you can damage the system. Have your water pressure checked, and if it is too high, have a water pressure reducing valve installed on your water supply pipe before you install a whole house water filter.

Consider using a pre-filter

A pre-filter acts as a sediment filter, preventing debris and other particles in the water supply from clogging your water filter. This investment can help extend the life of your whole house’s water filter system.

Install your whole house water filter system before the water heater

Don’t ignore this important part of the installation process. A whole house water filtration system is designed to work with cold water from your water line, not the heated water coming out of your water heater.

Talk to us now!

Our plumbing experts at our service have the training, expertise, and experience to work with you to evaluate your situation and recommend a water filtration system that meets your needs and matches your water supply. Our expertise with purification system installations at Enoch means we have the experience and knowledge to offer you a variety of options from highly-rated manufacturers. If you’re considering a water purification system, don’t delay, get in touch with us today. Quotes are free, and we’ll help you find the system for your home.

Water filtration is a general term that refers to any system or process that is used to filter out particles and pollutants from water. It doesn’t necessarily need to be a purifier to make the cut. Anything that removes any amount of particles, sediment, bacteria, and the chlorine taste can be called water filtration. If it has a filter of any type, it’s a filtration system.

Types of Filtration

Filtration systems can include activated carbon charcoal filters either designed within a pitcher or included as part of a faucet-mount or tap-installed filter, ultraviolet (UV) light units, reverse osmosis, water distillers (whole system or portable counter), or another form of water treatment process. The term incorporates home filter systems, as well as much larger scale municipal or public water treatment plants. Some appliances are also designed with water filtration features such as refrigerator models which come with onboard filtered water/ice or freestanding water cooler/dispensers.

There are many different types of water filters available, and your buying decisions will be influenced by the present condition of your water. If it’s not potable, you’ll need a process to remove or destroy harmful bacteria, minerals, and pollutants for starters. Your local water expert is the best professional to help you evaluate your choices.

Once water testing has confirmed what is in your water, you will be given remedy options to make your drinking water safe (potable). Installation requirements and costs will be discussed, based on needs and whether you own your home or not. Today, there are many choices, and these systems are much more affordable than they were a decade ago.

Keep It Clean

Whether you choose a small filter or a large unit, maintenance is key to keeping that system working efficiently. That means routine filter changes by yourself or by your chosen water specialist. If you have hard water or, for some reason, there is more sediment and particles in your water, it may require more frequent filter changes. Being proactive with care is an important part of any filtration process. Water filtration systems differ in size, price, installation, and efficiency, but they all in some way improve our water’s quality.

Home Filters

Water does not need to qualify as not being potable to benefit from some filtration system. One of the biggest consumer concerns is the chlorine taste left by town water treatment plants. It’s a necessary evil that results from measures taken to make your drinking water safe. You can, however, add an economical and simple filter system to reduce that if you wish to. A good alternative is also keeping a filtered water pitcher in the refrigerator.

Note that not all carbon filters, or larger units, have the same efficiency. There are differences in infiltration layers or stages, as well as in the quality of materials. That’s where the product details should be reviewed, so you know what the product will do for your water.

The featured is a good example of a simple measure to improve the quality of water. This is a popular choice for many because of its performance, easy install and affordable price.

In an emergency, water contaminated with germs can often be made safe to drink by boiling, adding disinfectants, or filtering.

Is your tap water safe to drink? Unfortunately, as discussed in the article Is Your Water Safe?, it may not be.

Because unhealthy levels of contaminants such as bacteria, lead, and pesticides are found in both metropolitan and well water supplies, it’s important to know whether pollutants exist in your water. And, if they do, you need to know how to supply your home with clean water.

Buying bottled water is the quickest and, initially, cheapest way to get clean drinking water. But over the long haul, it is far more expensive, and plastic bottles are wasteful and an environmental blight.

Producers of bottled waters are regulated by the same standards imposed on public water systems and are also self-regulated by the International Bottled Water Association. Club sodas, carbonated waters, seltzers, and waters containing more than 1 percent flavoring are not covered by these standards.

Water filters are the more permanent solution. Many types of water filters are made, and they range widely in sophistication and price. They may use reverse-osmosis, activated carbon, or ultra-violet rays to clean or purify water.

Should you buy an under-the-sink reverse-osmosis filter, or will a simple spout-mounted carbon filter do? Scores of companies claim to have the latest and greatest answer to your water needs. What are your other options?

The effectiveness of a water filter at removing specific contaminants depends upon the technology used. So, it’s important to know what needs to be removed from your water—and that involves testing.

This section of HomeTips explores the issues of clean drinking water, how to get water testing accomplished, comparing filter technologies, and how to install a water filter.

Types of Water Filters

If the only problem with your water is grit, dirt, sediment, rust, or other such particles, a screening filter may be sufficient. Made of fiber, fabric, ceramic, or another screening medium, these simply catch particles—including, in some cases, small organisms like cysts and some bacteria. But don’t rely on them to handle disease-causing organisms, VOCs, metals, or the like.

Carbon Water Filters

If your water tastes, smells, or looks bad, a filter containing activated carbon (AC) may solve the problem. If you want to remove chlorine, pesticides, herbicides, radon, trihalomethanes (THMs), and some inorganic chemicals, carbon may do the trick.

Some, but not all, carbon filters are effective at reducing lead content. Solid-block and pre-coat absorption filters trap lead. Check the certification of the unit you’re interested in buying and, if claims are made regarding lead removal, ask for proof.

You can’t rely on a conventional carbon filter to remove salts, nitrates, nitrites, and some metals. And you shouldn’t rely exclusively on one to remove organisms. In fact, be aware that a carbon filter will accumulate the contaminants removed from water, and bacteria may even breed in it, so you must replace filter cartridges religiously, according to the manufacturer’s recommendations.

A carbon filter that contains pesticide silver may be registered—but, remember, is not endorsed—by the EPA. Studies show that these are not fully effective at eliminating bacterial growth or microbiological contaminants. Again, be sure any such claims are substantiated.

Effectiveness of a particular carbon unit is a factor of the amount of activated carbon it contains. You can buy whole-house, under-counter, countertop, and faucet-mounted styles, but the $30 faucet-end models are only marginally effective. Known as point-of-entry (POE) systems, whole-house units are recommended where a contaminant such as radon poses a threat to the entire household.

Reverse Osmosis Water Filters

If you must remove inorganic chemicals such as salts, metals (including lead), minerals, nitrates, asbestos, and some organic chemicals, consider a reverse-osmosis (RO) water filter.

Actually, most models include carbon pre-filters and post-filters, which will catch sediment, pesticides, herbicides, THMs, and radon. RO filters remove lead, but some don’t remove chlorine (if this is claimed, request proof of performance). The carbon post-filter is used to improve the water’s taste.

Pre- and post-filter cartridges should be replaced annually.

Most RO filters are connected directly to plumbing and are located beneath the sink. A small tank stores clean water until needed, and tainted water drains out through a line connected to the sink trap. Drinking water flows through a special, separate sink-top spout.

Some models have an automatic valve that eliminates the waste typically associated with RO filters—conventional models waste about 3 gallons for every gallon of water they produce. They generally cost from $200 to $400.

Water Distillers

If you just want a portable, sink-top appliance that will rid water of most dissolved solids, such as salts, asbestos fibers, metals, minerals, particles, and some organic chemicals, an inexpensive water distiller may be just the thing.

Distillers heat water until it turns to steam and then condenses the steam back into water in a separate chamber, leaving behind anything that won’t travel in the steam.

Unless coupled with a carbon filter, they will not remove all chemical pollutants and all bacteria. Most have to be filled manually, they use a considerable amount of electricity to operate, and they may take several hours to produce 1 gallon of water. Prices range from about $80 to $400—most popular models are about $200.

UV Water Purifiers

Ultraviolet (UV) disinfection water filters, which typically cost $150 or more, may kill bacteria and viruses, and clear the taste and odor of water, but they are not effective against chemical pollutants and may not work against cysts and spores. UV may be combined with carbon filters to kill bacteria; these units tend to cost from $300 to $700.

Buying a Water Filtering Faucet

With the popularity of water-treatment devices, a number of manufacturers have introduced products that integrate water systems seamlessly into the kitchen. For example, American Standard makes the Streaming filtering faucet that works with an under-sink filter to deliver filtered water through the main kitchen faucet.

Frigidaire offers a built-in PureSource Ice & Water Filter in its Gallery Side-by-Side refrigerators, and the GE Profile Performance Side-by-Side refrigerator offers a “Water by Culligan” built-in filter. Just be sure whatever product you buy utilizes the type of filter needed to mitigate your water problems.