What to Look For In a Water Filter
With the various types of water filters out there, finding the right system doesn’t have to be as confusing or challenging as it might seem. Knowing what to look for in a water filter can help you seek out the features that will give you the most benefit. Understanding common water filter features can help you separate hype from what really works, leaving you with a system that will meet your needs for years to come.
Water Filtration Breakdown
Let’s start by discussing what water filtration is. Water filtration is the process of removing contaminants or unwanted substances from contaminated water through the use of physical, chemical, or biological media.
In a residential setting, this is most often done through the use of physical filtration using a semipermeable membrane in reverse osmosis systems, or a multi-media system with at least one filter consisting of activated carbon.
Water Filtration vs. Water Softening
Water softeners also remove unwanted material from a water source, but it is important to understand how water softening systems and clean water filtration systems are different. In a sense, water softening is a type of filtration because they remove hard minerals from water. These minerals are usually calcium carbonate and magnesium, but water softeners can also remove heavy metals that contribute to water hardness like lead, copper, and iron.
Water softening systems function through a process known as ion exchange. Hard water is passed through a tank containing resin beads with sodium ions attached. As the water passes over these beads, the mineral ions attached to the water molecule are attracted to the resin beads and replaced with a sodium ion. Periodically, the minerals attached to the beads are flushed from the system.
In contrast, water filtration involves passing water through a physical object through which water molecules can pass but many contaminants cannot.
Here’s where it gets tricky; some water filtration systems can provide water softening as well. For example, reverse osmosis systems can soften water by reducing the content of minerals and heavy metals contained in the water source. The reverse is not true. Unless a water softening system has pre- and post-filtration using another type of media like activated carbon, it will not filter out common contaminants like disinfectants, microbes, solvents, or pesticides.
Due to this, many people who want the benefits of soft water but also want filtered drinking water use systems that offer both softening and filtration, or use both a water softener and a water filtration system in their home.
What Contaminants are in Your Water?
In the United States, unless your water comes from a private well, it has probably been treated in some way before it enters your home. In spite of this, tap water often contains contaminants that you may not want to drink or use to bathe. Despite regulations that should ensure our drinking water is safe from outside pollutants, each year drinking water violations occur that expose individuals to potentially harmful chemicals. At the same time, the chemicals used to disinfect contaminated water may not be ideal for long-term consumption.
Here are a few of the most commonly found contaminants in tap water across the United States:
- Heavy metals like lead, copper, and iron
- Disinfectants and disinfectant by-products
- Perfluoroalkyl and polyfluoroalkyl substances (PFAS)
- Industrial solvents
- Bacteria, viruses, and parasites
Water quality violations occur all the time, but we often don’t know about them until after the fact. This highlights the importance of having an effective filtration system in place even before you know that a violation has occurred.
In order to choose the most effective filtration system to meet your needs, it’s a good idea to have the water in your home tested. While you can get a fairly good sense of the state of your tap water through water quality reports that most community water suppliers in the United States publish, those reports only provide a snapshot of water quality. They also don’t account for contaminants that might be picked up through the delivery system on the way to your house, such as lead being leached from the pipes.
Getting the water tested in your home is a great starting point for narrowing down the water filtration system that will meet your needs. It is also important to understand water quality changes over time depending on a variety of factors. Utilizing a filtration system that can remove or reduce a broad spectrum of contaminants can help protect against short-term increases in contaminants.
Water Filter Features
Each filtered water system has a variety of features that may seem daunting at first. Let’s take a look at some of the most important water filter features, why they are important, and what they might mean for you.
Most water filtration systems will feature their filtration method first, or list the filtration methods if more than one is being used by the system.
The two most common filtration methods are activated carbon filters or reverse osmosis filters. This feature will be a decisive factor in your search for a water filter because each filtration method is effective at some contaminants but not others.
Reverse osmosis is effective against:
- Microbes (viruses, bacteria, protozoa)
- Heavy metals (iron, copper, lead)
- Salts, calcium, and magnesium
Activated carbon filters are effective against:
- Industrial solvents
- Disinfectants and disinfectant by-products
- Volatile organic compounds (VOCs)
Reverse osmosis filters are highly effective at removing a range of contaminants that are often the source of water quality violations. These include bacteria like Salmonella and E. coli, protozoa like Giardia, heavy metals, nitrates which enter the water from fertilizer runoff, and arsenic which is commonly found in wells.
In contrast, activated carbon filters tend to be more effective against organic compounds, as well as disinfectants like chlorine which are used in water treatment. These substances can give water a bad odor and taste as well. Activated carbon filters won’t capture the heavy metals, mineral ions, and microbes that an RO system will.
Once you’ve had your water tested you should have a better idea of what contaminants your water contains. This can guide you towards a system that is going to be most effective at filtering the water at your tap. However, you may also consider combining both of these filtration methods. This has the advantage of removing a broad spectrum of contaminants from your drinking water.
Total Dissolved Solids
Most filtered water systems will provide you with the number of total dissolved solids (TDS) that they remove. Most people aren’t sure exactly what TDS are, so let’s break down this term is and what you should be looking for in a water filter system.
TDS refers to the number of salts, minerals, and organic matter that is in a sample of water. Most often, these dissolved solids consist of calcium, magnesium, sodium, potassium, sulfate, nitrate, and chloride. This is expressed in terms of mg/L.
The dissolved solids in your tap water enter the water supply in a number of ways, some natural and some not. Sources of these solids include industrial wastewater, agricultural runoff, sewage, and even road de-icing. Natural processes can also increase the number of TDS in water. For example, as water passes through chalky soil it can pick up calcium carbonate which hardens the water naturally.
Even though the TDS in your tap water is probably altering the taste of your water, you’ll need to have your water tested to tell exactly what the TDS of your water is. Water filtration systems often feature the reduction rate for TDS. Choose a system that offers a high removal rate for TDS. Many systems will offer a range of TDS they remove, such as 93% – 97% of TDS. So, for a sample of water with a TDS of 300 mg/L, water produced by a high-end reverse osmosis system will have only 9 – 15 mg/L TDS.
One last feature to pay attention to is the output of the desired system. Water filter systems have a wide range of outputs. Point-of-use systems might have an output of 10-50 gallons-per-day (GPD). Whole-house filters, such as point-of-entry systems that provide filtration or conditioning for your whole house might have an output of thousands of GPD.
35 – 50 gallons a day will be more than sufficient for providing drinking water for everyone in your house, making ice cubes and coffee, or doing the dishes. But if you want to have your shower water filtered, you will probably want to look for a system that has a higher output.
Water filtration can be a confusing topic to dive into. This breakdown should help you identify the water filter features that matter most. The type of filtration method that the system uses is the most important feature you should be mindful of, as this will determine which contaminants the system is removing from your water. If you’re interested in more information, visit our guide comparing water filters vs. reverse osmosis systems.
Being mindful of the TDS removal capability of the system is important as well as an indicator of how effective the system actually is at reducing certain contaminants. The output of the system you end up with will largely depend on how to install the water filter and what you need it for. Point-of-use systems tend to have a lower output and are more appropriate to provide filtered drinking water at a specific tap, while point-of-entry systems filter or condition clean water for your entire house.
Before investing in a water filtration system you should consider having your water tested. Having a better understanding of what contaminants are in your water can help guide you towards the system that is right for your needs. At the same time, consider investing in a system that uses more than one filtration method. For example, a system that utilizes reverse-osmosis with pre- and post-filtration through activated carbon will reduce a wider range of contaminants than a reverse-osmosis system on its own. This will help protect you against contaminants that may appear in your water supply in the future.
To learn more about water filter options or to schedule a water quality test, please contact us for more information.