Watertechadvice.com is supported by readers. If you purchase through referral links on our site, we make a commission at no extra cost to you. Learn more.

Home » Water Filtration Systems » Whole House Water Filter Vs Under Sink Filter

Whole House Water Filter Vs Under Sink Filter

By: Craig Smith
Published on:
Whole House Water Filter Vs Under Sink Filter

As you look to take steps to enhance the water coming into your home, you will have some choices to make.

One of the toughest of these decisions is deciding whether to install a whole house water filter or under sink water filter.

That’s where my 27 years of water filtration experience can help. Here I will talk about everything that is pertinent when looking at a whole house water filter vs under sink filter.

As you read on here, you will discover that purchasing either system can only benefit you. That benefit is further increased by combining these water filtration systems together if you choose to do so.

Whole House Water Filter Vs Under Sink- What’s Difference?

All water filters fall into one of two categories. They are as follows:

1. Point Of Entry (POE) Water Filters

Point of entry types of water filters are appropriately named because they will be connected to your incoming water line in a place very close to where that line comes into your home.

The biggest benefit of this is that they will treat 100% of the water you use in your home for drinking, bathing, and other purposes.

A whole house filter falls into this category.

This is because in most cases they will consist of a large single media tank or a series of filter cartridges which are installed very near to where your incoming water line enters your home.

2. Point Of Use (POU) Water Filters

POU water filters are quite different from point of entry water filters because they are installed for just a single purpose on only one water tap. 

These can be a filter that enhances your drinking water quality or a shower filter that protects your skin from chlorine damage.

Under sink water filters fall into this category because they only improve the quality of water coming from a single faucet in your home.

This is much unlike whole house water filters that treat virtually every drop of water that comes into your home.  

What Are the Benefits of a Whole House Water Filter?


Here are some of the main reasons that you would choose to install a whole house filter as opposed to an under-sink filter:

  • 100% of the water coming into your home will have the contaminants that your filtration system specifically targets removed or reduced.
  • The filter media is large enough to last a long time.
  • They usually feature technology that consists of multiple layers of different types of impactful filter media.
  • These systems can be made to go beyond just improving the quality of your drinking water such as added water softeners that prevent limescale buildup in plumbing fixtures.
  • Whole house filters can protect appliances that use heating elements and have water pass through them.

What Are the Benefits of An Under Sink Water Filter?

iSpring Water Systems Under Sink

This is why many people choose to install under sink filters:

  • They usually have a lower initial purchase price
  • Under sink filters can be purchased to target very specific contaminants in your tap water that concern you
  • These filters are aesthetically pleasing because they are hidden from sight
  • They don’t require a lot of space to set up
  • No permanent changes to the plumbing are necessary
  • Sometimes offer more effective filtration for drinking water if reverse osmosis is included

Water Testing

When determining which of these water treatment devices are right for you, several factors must be considered.

This includes your budget range, product availability, system placement, and other considerations.

But nothing is more important in making a whole house water filter vs under sink filter decision than testing your home’s water before you start your search process.   

Don’t use a basic test to do this either. Use a more sophisticated test kit such as those made by Tap Score that uses lab analyses to test for a wide variety of concerning water contaminants.


This takes on even more importance if you have well water coming into your home because of the possibility of it having so many unhealthy contaminants in it.

Once you have tested your home’s water for the contaminants that are present in it, this will help make your decision easier.

Take a case where water testing revealed that you have an unusually high amount of iron in your tap water.

Most under sink filters do not effectively target iron, so the preferred choice here would be a whole house filter.

So, water testing is critical when it comes to making decisions regarding water filter purchases.

Get a Water Test Kit Here

Combining Both Types of Filters

Still having trouble deciding whether a whole house or quality under sink filter is right for you?    

That may be a good thing and alert you to another possibility. That’s combining these two types of water filters to form an even more impactful water filtration system.

That will give you general whole house protection against a variety of different water impurities and even more improvement to the water quality from your kitchen faucet that you drink and cook with.

This will give you the best of both worlds and give you some nice peace of mind as far as your water quality is concerned too.

I have this type of setup in my home.

Installed in my home is a water softener that treats 100% of the water coming into my house and an under-sink filter that improves the quality of my family’s drinking water and better protects their health.  

So Which Water Filter is Best for You?

There is a reason that I chose to write for Water Tech Advice. I am passionate about informing people as to why they need to clean up the water that they drink and use.

Well water almost always needs some form of filtration performed on it and even city water that comes into your home already treated has some unwanted impurities.

So even the purchase of something as simple as a water pitcher I support.

By purchasing a whole house filter or under sink filter, you will be taking steps that will take your home’s water quality to a much higher and healthier level.

To me there simply is no bad choice when it comes to which one of these filtration systems that you choose to install.  

As was mentioned above, combining them in most cases should form a very impactful water treatment system in your home.

I remind you again, that water testing plays a critical role in your filter selection process. 

Check out the best whole house filters or under sink filters here.

Photo of author
Craig Smith
Craig got his start in water working in the swimming pool and spa industry. Water treatment would grow into his main career but he ended up working in the pool industry for over 26 years where much of his time was spent balancing the water in customer's swimming pools and installing water filtration equipment. Craig offers an abundance of water treatment knowledge after helping homeowners get pure water for 26 years.

Learn More About The Water Tech Editorial Team