What Do Under-Sink Water Filters Remove?

Under-sink water filters have become a popular choice for homeowners seeking clean and safe drinking water right from their taps. These filters employ various technologies to target specific contaminants, ensuring water quality meets desired standards.

Under-sink water filters can remove sand, sediment, chlorine, chloramines, fluoride, sulfur, pesticides, and other hazardous chemicals from your water. Quality filters even eliminate nasty odors and unpleasant tastes, giving you pure and fresh water to drink.

In this article, we will explore the contaminants that under-sink water filters are designed to remove.

What Are Under-Sink Water Filters?

An under-sink water filter is a filtration system that fits below your kitchen or bathroom sink. They contain one or more water purification stages to eliminate contaminants and impurities from your home water.

Most commonly, under-sink water filters contain activated carbon as the filter media. However, many units also use ion exchange resin, sediment cartridges, catalytic carbon, KDF, and more to target water pollutants.

Although a few homes only need basic filtration media like sediment or carbon, others may require a more advanced system to boost water quality.

Fortunately, under-sink water filters can effectively target tons of contaminants from fluoride to chlorine and heavy metals to Per- and Polyfluorinated Substances (PFAS).

Contaminants Removed by Under-Sink Water Filters

1. Sediments:

Under-sink filters often feature a sediment pre-filter that efficiently removes larger particles such as sand, silt, and rust. This step is crucial as sediment can affect water clarity and taste.

2. Chlorine and Odors:

Activated carbon filters, a common component of under-sink systems, excel at eliminating chlorine taste and odor. Chlorine is commonly used in municipal water treatment but can impart an unpleasant taste and odor to tap water.

3. Heavy Metals:

Certain under-sink filters are equipped to reduce heavy metals like lead, mercury, and cadmium. These harmful substances can leach into water from pipes and plumbing fixtures.

4. Microorganisms:

Some under-sink systems incorporate UV (Ultraviolet) or reverse osmosis (RO) technology to effectively eliminate bacteria, viruses, and cysts from the water supply. This is especially important for ensuring microbiologically safe drinking water.

5. Chemicals:

Under-sink water filters can target various chemicals, including pesticides, herbicides, and volatile organic compounds (VOCs). Removing these contaminants enhances the overall quality of the water.

6. Dissolved Solids:

Reverse osmosis systems excel at removing dissolved solids, such as minerals and salts, from the water. This is especially valuable in areas with hard water, as it improves taste and reduces scaling in appliances.

7. Pharmaceuticals and Emerging Contaminants:

Some advanced under-sink filters are designed to address emerging contaminants like pharmaceutical residues and personal care products. These filters use advanced media to adsorb and remove these substances.

8. Total Dissolved Solids (TDS):

Filters with reverse osmosis technology can significantly reduce the Total Dissolved Solids (TDS) in water, improving taste and reducing the presence of minerals and salts.

9. Volatile Organic Compounds (VOCs):

Activated carbon filters are effective at removing VOCs, which can originate from industrial processes or household products. This filtration process can lead to healthier and better-tasting water.

How Do They Work?

The working of a standard under-sink water filter is relatively straightforward. Here are a few steps explaining how they purify water.

  • Once installed, the filter receives the water through a flexible tube attached to your cold water line below the sink. The tube directs your home water to the filter.
  • Next, the water leaves the filter via another flexible tube and is directed to the filter’s faucet installed on your sink’s top or through your pre-existing cold water tap. This means the water doesn’t get mixed with unfiltered water.
  • When you turn on the filter’s faucet, the water flows via the filter out of the tap due to pressure on the unit.

Simple under-sink filters direct the water through the filter, which dispenses only via your sink’s regular cold water faucet. So, water from the cold faucet is filtered while the hot water remains unfiltered.

Different Types of Under-Sink Water Filters

There are multiple under-sink filters to choose from. This is because water filters aren’t a one-size-fits-all solution. Each water filter removes specific impurities from the water. You should purchase a type that works well to remove particular contaminants present in your home water.

Single Stage Under-the-Sink Water Filters

As the name implies, single-stage under-sink filters only contain a single filter media to clean your drinking water. While these systems work effectively, their efficiency depends on the filter media type for the most part.

Multi-Stage Under-the-Sink Water Filters

Multi-stage under-sink filters contain 2 or more filtration stages to clean your drinking water. Generally speaking, most multi-stage filters contain a sediment filter cartridge as the first stage. An activated carbon filter typically follows it to boost water aesthetics.

However, there are many filter types for a single or multi-stage under-sink filter. Here are main cartridge types and the contaminants they can remove:

i) Carbon Block

Carbon block filters are designed by sticking together powdered carbon to create an emulsion. The fine mixture is then compressed into cartridges to purify your drinking water.

Most carbon filters can effectively remove total suspended solids, heavy metals, volatile organic compounds, sediment, and other impurities from your water.

ii) Sediment Filters

Sediment filters are the most widely used single-stage filtration systems, and rightfully so. Several US citizens encounter an issue of dirt and sediments in their drinking water. Sediment filters easily remove all the floating particles, purifying your water.

They can eliminate rust, dirt, debris, and dust particles swimming in your water. However, they do not remove salts, chemicals, or other impurities.

iii) Granular Activated Carbon

You cannot go wrong with granular activated carbon if you seek an advanced single-stage under-sink filter. The system is carefully designed with a highly porous material. It produces chemical reactions with an absorption technique to purify the water.

Apart from eliminating several water chemicals like disinfection byproducts and pesticides, granular activated carbon also removes unpleasant tastes and nasty odors from the water.

Besides, the high flow rate is another attractive feature that makes it a consumer favorite.

iv) KDF Filter Cartridges

KFD filter cartridges purify water through redox reactions. The filter cartridges comprise a copper-zinc mixture to eliminate lead, mercury, chlorine, hydrogen sulfide, and chromium from the water.

Besides, KDF filter cartridges also effectively inhibit bacteria growth in your filtration system that may otherwise contaminate your water.

A few manufacturers also use KDF filter cartridges in multi-stage under-sink systems to support and strengthen the functionality of carbon filters.

V) Catalytic Carbon Filter Cartridges

Catalytic carbon is yet another filter system containing carbon as its filter media. Experts believe it is suitable for eliminating hard-to-remove chemicals from your water. Generally, activated carbon doesn’t effectively remove chloramine; catalytic carbon cartridges perform the job reasonably well.

So, if you’re buying a single-stage filter and seek to eliminate disinfection chemicals in your drinking water, consider purchasing a catalytic carbon filter.

vi) Activated Alumina

An activated alumina filter is the right choice for homeowners who want to eliminate stubborn traces of arsenic, uranium, and fluoride from their drinking water.

These filters are known for their hassle-free installation, affordable price tag, and easy repairs. Besides, low maintenance cost is another perk of activated alumina filters.

vii) Ion Exchange

Many home filters use ion exchange to target specific water contaminants. Most of the filters help eliminate inorganic substances like sulfate and arsenic.

However, because it effectively eliminates specific contaminants, purchase it only if your drinking water has the specified inorganic substances. Put simply; it won’t target other water contaminants.

Are Under-Sink Water Filters Worth It?

Under-sink water filters are generally worth it if you want consistent access to clean and safe drinking water. They offer several advantages, including improved water taste, reduced exposure to contaminants, and reduced reliance on bottled water, which is cost-effective and environmentally friendly.

The worthiness of a specific filter depends on your water quality and filtration needs. You may want to conduct water testing to identify specific contaminants before choosing a system.

How Long Do Under-Sink Water Filters Last?

The lifespan of under-sink water filters varies based on the type of filter and water usage. Typically, the filter cartridge or element needs replacement every 6 months to 2 years. Follow the manufacturer’s recommendations for replacement intervals.

For example, a carbon filter might last around 6 months, while an RO membrane can last 2-3 years. Factors like water quality and usage affect filter longevity.

Are All Under-Sink Water Filters the Same?

No, under-sink water filters come in various types and configurations to target specific contaminants. These include carbon filters, reverse osmosis systems, UV purifiers, and more. Different filters have different capabilities.

For instance, carbon filters are excellent at removing chlorine and improving taste, while RO systems are effective at removing a wide range of contaminants, including dissolved solids.

Do Under-Sink Water Filters Reduce Water Pressure?

Some under-sink water filters, like reverse osmosis systems, can reduce water pressure. RO filters work by forcing water through a semi-permeable membrane, which can slow down the flow rate.

However, many modern RO systems include features like booster pumps to mitigate this issue. Other filters, like carbon or sediment filters, typically have minimal impact on water pressure.

Under-sink water filters may also reduce water pressure due to clogged filters, kinks in the water line, closed valves, and blocked aerators.

A few users often complain that under-sink water filters cause water pressure drops. However, technically speaking, the filter per se isn’t responsible for the pressure decline. In fact, it aims to provide fresh and pure drinking water. Instead, an underlying issue contributes to reduced water pressure. You only need to spot and fix the problem to enjoy optimal pressure flow.

  • Inspect the filter elements for clogs. A worn-out filter cartridge might drop the water pressure. Replacing it will fix the problem, however.
  • Bends or turns in the water tubing also lead to reduced water pressure. You can always fix the kink to improve the water flow.
  • Make sure all water valves are open to the maximum capacity to enjoy optimal water pressure levels.
  • The aerator screen is often the culprit of reduced water pressure. So, gently remove the aerator and dip it in vinegar overnight to clean the debris. You can also use a needle to open the clogged holes of the aerator and improve the water pressure.

Why Should I Invest In an Under-Sink Filter?

Investing in an under-sink water filter can provide numerous benefits:

Improved Water Quality: Filters remove contaminants, making your water taste and smell better.

Health and Safety: Filtration can reduce exposure to harmful substances like lead, bacteria, and chemicals.

Convenience: Enjoy access to clean water directly from your tap without the hassle of purchasing and storing bottled water.

Ultimately, investing in an under-sink water filter can lead to better health, convenience, and cost savings while contributing to a more sustainable lifestyle.

Final thoughts

In conclusion, under-sink water filters are not a one-size-fits-all solution; they are tailored to address specific contaminants depending on their filtration technology. When selecting an under-sink filter, it’s crucial to consider your local water quality and your specific filtration needs. Regular maintenance and following manufacturer recommendations for filter replacement are essential to ensure continued contaminant removal effectiveness.

Theresa Orr

Theresa Orr is an Earth Scientist who specializes in determining past climates from rocks using geochemistry. Her passion for clean water drives her to breakdown the science to provide easy to understand information that everyone can read.

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