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How to choose Under sink water filter

The economical way to provide your family with a lot of filtered water safe for human consumption is by installing under sink water filter. The filtration method provides filtered water straight from the tap without taking up countertop space. There are different types of under sink water filters and each works differently. Here is a guide on how to choose under sink water filter that will suit you.

best under sink water filter

How to choose Under sink water filter

There are a few features you should consider when buying under sink water filter. These include:

  1. Types of under sink water filter

There are two different types of under sink water filter

  1. convectional 
  2. simple/ direct inline.

Both types use cartridges combined with other technologies to provide filtered water, but installation is different.

Simple/ direct inline under sink water filter
As the name suggests the inline under sink water filter works effectively to remove all contaminants but how it is being installed is not complicated/ it is simple.

It is mounted directly into the main water line under the sink in your kitchen.

All the cold water that gets in your kitchen sink’s main water line is diverted through the filter to be filtered.

The simple system is installed in an already existing faucet. No drilling/no separate faucet is required.

Advantages of direct inline

  • It doesn’t require a separate faucet for filtered water and unfiltered water.
  • This type is easy to install you do not drill a hole for an extra faucet.

Disadvantages of the direct line

  •  It is connected to the kitchen sink main cold water pipe/line so a lot of water is filtered so you will have to change the filter more often therefore maintenance can be expensive.
  • If the water reaching the filter has high pressure it will overwork the filter and some water will pass through unfiltered.

Shop for the best inline under sink water filter

 NameImagefilter lifeContaminantsReplacement filterWhere to buy
1Woder under sink water filtration system10,000 gallons or 3-years.Heavy metals, Chlorine, turbidity, Chromium 6, Volatile Organic Compounds, Mercury, lead, odors and bad tastesN/AAmazon
2CuZn UC-200 Under Counter Water Filterunder counter water filter50,000 gallons or 5 years.organic, inorganic chlorine, heavy metals (lead, mercury, chromium VI, cadmium, etc.), herbicides, pesticides, sediment, algae, molds, bad taste, and odor.N/AAmazon
3Watts Inline Water Filterinline water filter20,000 gallonsChlorine, odor, contaminants, sediment, and particulatesN/AAmazon


The conventional is the opposite of simple its installation is complicated.

You need to divert the kitchen sink’s main cold water pipe/line to the filter using a connection.

When the water is filtered, it is sent to the separate faucet installed in the sink.

You will have two taps one for cold filtered water and the other one for cold unfiltered water.

This type will make your filter last longer because not all water that gets to your kitchen sink’s main cold water pipe/line is filtered.

In the conventional system, the pressure is reduced so all water that enters the system will get filtered.


  1. You require a sink that has two faucet holes if not drill an extra hole in the sink
  2. It reduces the water flow rate 
  3. Requires plumbing for you to install the system.
  4. The conventional system, the water pressure is low, therefore, you can wait for a few minutes before you get a full glass of filtered water.

Shop for the best convectional under sink water filter

 NameImageContaminantsReplacement filterWhere to buy
1ApecUndersink water filtersbad odor, colors, chlorine, taste, particles, dust, and rust
Filter life: 1000 capacity
2Culligan US-EZunder sink water filter with dedicated faucetparticulates class III, chloride and removes bad taste and odor
Filter life:3000 gallons
3Aquasanalead, mercury, pesticides, pharmaceuticals, chlorine taste, odor, particulates, cryptosporidium, asbestos, herbicides, detergents, pharmaceuticals, and other volatile organic chemicals
Filter life: 800 gallons
4Doulton W9330958 SuperCarb Under Sink Filter SystemDoulton under sink filterfine particulate matter, bacteria, cysts, turbidity,  pathogenic bacteria, hydrogen sulfide, lead,chlorine, taste, odor and organic compounds.Amazon
5Whirlpool WHADUS5Convectionalchlorine taste and odor, sediment, cysts, lead, and chemicals.
Filter life: 6 months
6Frizzlife under sink water filterlead, heavy metals, chlorine, chromium, mercury, rust, volatile organic compound, carcinogens, turbidity, odor and bad taste.Amazon
7Ecosoft 3 Stage Under Sink Water Purifier Filtration System  chlorine taste and odor, salinity, lead, iron, manganese, tannins, dust, rust, and sedimentAmazon
8Brondell H2O+ Coral UC300 chlorine taste and odor, heavy metals (such as lead and mercury), industrial chemicals (like benzene), total dissolved solids, volatile organic chemicals Amazon
9iSpring US31 3-Stage Under Sink dust, particles, dust, and dirt, cloudiness, chlorine taste, and odorAmazon
10Watts Premier WP500313 2-Stage Undercounter simazine, atrazine, benzene, trihalomethanes (TTHM), lindane, xylenes, entamoeba cryptosporidium, giardia, chlorine taste, and odorAmazon
113M Aqua-Pure Under Sink Water Filtration System  particulate, rust, lead, VOCs, MTBE, parasitic protozoan cysts, chlorine taste, and odor.Amazon
12Watts WP2BVC Premier Bacteria, Virus, & Cysts
chlorine taste and odor
13Watts Premier 500320 with Ultravioletlead, cysts, particulate matter, chlorine taste, and odorsAmazon
14New Wave Enviro-30008 chlorine, trihalomethanes, organic and inorganic arsenic, mercury, lead, pesticides, and herbicides.Amazon
  1. Which contaminants it removes

Under sink water filter has a combination of the filter with different technologies which each removes the specific contaminant such as

Bad Odor and taste

Since the system has a carbon-activated filter that helps remove chlorine odor and taste.
Also, an activated carbon filter removes organic, inorganic chlorine, heavy metals, herbicides, pesticides, algae, and molds.

Removes heavy metal
The carbon filter combination removes heavy metals such as lead, mercury, chromium VI, and cadmium.

Particulate removal
The system has a polypropylene sediment filter that removes particles, dust, silt, and rust.

Reduce hard minerals (calcium and magnesium) that form scale on home appliances.

Not all systems are designed the same so make sure you purchase the system that filters contaminants present in your water.

You can use a water test kit to know the contaminants present in water.

  1. Easy to install and maintain

Most of these systems are easy to install they come with the DIY installation process that you can do alone at home without hiring a professional.

Since the system use cartridges that require to be replaced after a period the replacement should be smooth and straightforward.

  1. Filtration technology

Under sink water filter removes contaminants using different techniques such as

The reverse osmosis method uses a membrane. Contaminated water is forced to pass through the tiny pores of the membrane. The tiny pores only allow clean water to pass through and impurities are flushed to the drain. The method helps remove the total dissolved substance and heavy metals.

Find out the best systems that use the reverse osmosis method

Carbon-activated filter that helps remove organic, inorganic chlorine, heavy metals, herbicides, pesticides, algae, and molds, chlorine odor, and taste.

Ultrafiltration method

Some brands go up to six stages which include alkaline remineralization. The stage adds essential minerals such as calcium and magnesium.

Check the system that has the most filtration technology because will help save a lot of money and space.

Also, the more the filtration stages the better because the system will provide quality filtered water.

  1. Filter life

Under sink water filters use cartridges to filter contaminants in the water.

The cartridge doesn’t last forever so requires to be replaced.

You should know how long the filter will last for it to be replaced.

Some brands need their filter to be replaced after filtering specific gallons or a few months, but this can be different due to some factors such as quality of water and amount of water filtered. 

You should follow the manufactures instruction on when to change the filter.

Some companies have a filter indicator to inform when it needs to be replaced.

  1. Water flow/ pressure

As we said earlier if your water pressure is high and you are using a simple system some contaminants will escape and pass through unfiltered.

In the conventional system, the water pressure might be low, therefore, you can wait for a few minutes before you get a full glass of filtered water.

Know the flow rate of your system or water supply pressure before buying the filter.

  1. Independent certification

Independent certification is the only way to guarantee your water system removes contaminants effectively and is made with quality material.

There are independent bodies such as NSF and WQA that test and approve most water systems.

Under sink water filter installation

I have prepared a list of websites to guide step by step how to install under sink water filter.

This video might be a help too.

Under sink water filter is one of the best ways to make sure your family always has enough clean water for drinking regardless of the contaminant from the treatment plant or pipes.

Hoping our guide on how to choose the best under sink water filter will help find the right product you need for your home.

If there is a brand you want us to add to the list above, please let us know in the comment section below.

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