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Home » Water Filtration Systems » Should I Install My Whole House Water Filter Before or After the Water Softener?

Should I Install My Whole House Water Filter Before or After the Water Softener?

By: Craig Smith
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As you have become more aware of the need to enhance the quality of the water coming into your home, you may have taken steps to purchase and install a water softener or a whole house water filter.

It may even be a case where you have both. Many people do. That leads me to ask the question if you are sure that you have these water treatment devices positioned properly in respect to one another to maximize their efficiency.

This is something that is especially critical to get right and becomes even more important to know if you are about to purchase and install these systems on your incoming water supply line.

So, should you install your whole house water filter before or after the water softener?

The answer to this question is not as straightforward as it may seem because several factors go into determining whole house water filter versus water softener placement.

That’s why I would like to discuss this very thing in much more detail. By the time you are done reading, you will understand much better whether your water softener or whole house filter goes first on your incoming water line.

The Difference Between Water Filters and Water Softeners

Here are the main reasons why you would purchase and install either of these water purification devices:

Water Softeners


One of the main water problems that occur in many households across America is having water that has too much hard water causing minerals such as calcium and magnesium present in it.

This is especially true if your incoming water comes from a well. Something that has been confirmed by a United States Geological Survey (USGS) study.

Having hard water causes such nuisance problems as hard to clean and unsightly limescale on bathroom surfaces and fixtures along with causing spotty dishes & glasses and potentially clogging your plumbing.

Water softeners work using an ion exchange process that removes hard water minerals from the water to eliminate hard water-related issues.

Whole House Water Filters


There are a large variety of types and purposes of whole house water filters (also called point of entry, media, or whole home filters.

Their main purpose is to improve the aesthetic quality (looks, taste, and smell) of your drinking water and to also remove or reduce several harmful water impurities.

These systems can even be designed to target specific impurities in your household water that are a concern for you.

One trait of these worth noting is that they will enhance 100% of the water that comes into your home.

This is much unlike other types of water filters such as water pitchers, under-sink water filters, and countertop water treatment devices.

Do You Need Both?

It’s a fair question to ask if you should have both of these water purification devices in place and working for you in your home?

The only way that you can know for sure is by having your home water tested for hard water-causing minerals and other impurities to determine if either of these water enhancement devices would be a recommended purchase for you.

For this purpose, I would recommend that you get professional lab analysis of your household water done. That’s because these tests are used to detect the levels of a large variety of common home water contaminants.

Some of my favorite test kits for doing this are ones like the Tap Score city and well water test kits. You simply order them online, fill up the water sample containers that are included in the kit, and then send them to the company.


In a few days, you will get the results of that water testing sent to you in an email.

If that testing reveals you have a high level of hard water minerals and many other contaminants in your tap water, then you can benefit from having both a water softener and a whole home water filter.

Whole House Filters: Before or After Softeners?

Where to place your water softener and whole home water filter on your incoming water supply line is not as easy a decision as you might think.

Here are some of the factors that determine where on your incoming water line you should place your point of entry (POE) water filter and water softener:

1. Water Source: Municipal or a Well

Although city-supplied water will never be accused of being highly purified water, it generally will come into your home pretreated and free of visible water contaminants. That is not always the case with well water and its quality is much more unpredictable.

This means that for city water, whether you place your point of entry filter system will be determined by other factors but for well water users, you will want to place your whole house filter before your water softener.

2. Sediment Levels in Your Incoming Water

The amount of sediment in your home’s water, which more often than not occurs with well water, is definitely a factor when it comes to point of entry filter and water softener placement on your waterline.

That’s because you would not want your water softener to be the first water treatment device that your incoming water comes into contact with. This is because they are not designed to deal with large amounts of sediment.

Sediment coming into a water softener will not only significantly impact its efficiency, but may also even ruin it.

So, in cases where you have a lot of sediment in your water, it’s always best to place a whole house filter that has a quality sediment pre filter before the water softener.

3. Has Your Incoming Water Been Treated with Chlorine?

Although some well water users do treat their water with some type of chlorinating device, this is a much more common factor in water softener versus whole home water filter placement if you are on a municipal water supply.

It’s used to make water safer to drink because it kills bacteria, parasites, and viruses very effectively. While whole home water softeners are usually very effective at chlorine removal, chlorine can be very detrimental to water softeners.

That’s because it tends to cause the divinylbenzene (DVB) that many resin beads are made of to both swell and become less porous. This will shorten the life of the resin beads in your water softening system and cause them to work less efficiently.

So, when you have highly chlorinated water coming into your home, you should always place your point of entry water filter before your water softener.

4. Iron Level in Your Water Supply

High iron and manganese content in your incoming water supply may cause red stains on your clothes and other lighter-colored items that you wash.

Although water softeners will remove some of the iron that passes through them in your water, they are not designed for this purpose.

Water softeners with standard crosslink resin can handle iron levels of 3 to 5 ppm and much more expensive fine mesh resin will do even better. 

But for cases when you have a higher amount of iron in your water than this, you will be better served by pacing a POE water filter before your water softener.  

Springwell CF1 Whole House Filter

An iron filter is the most effective type of whole house filter to place before your water softener if you have high iron content in your household water.

Do You Have a Salt-Based Water Softener or Media Type Whole Home Water Filter (These need Backwashing)?

Media type whole home water filters and salt-based water softeners require period backwashing to keep them clean and working efficiently. Backwashing is a process that requires a certain amount of water pressure for it to be effective.

The amount of pressure that’s required to properly backwash these water treatment devices should be stated in the owner’s manuals for them. 

Also stated in this information should be the water flow in gallons that results after your water supply has passed through them.

After looking at this information, if either your water softener or whole-home water filter will reduce the water pressure so much that the other will not be able to perform a proper backwashing cycle, then it must be placed last on the incoming water line.  

Summing Up Whole House Water Filter Placement When Working in Combination with a Water Softener

In most cases, you can never go wrong with having a water softener or a whole home water filter in place and working on your incoming water supply line. Having both working together is even better.

But as you have learned in this article, proper placement of them in regards to each other is very important. Here is a summation of what was discussed:

Whole House Water Filters Go First When:

There is a large amount of sediment in your incoming water

Your incoming water supply is highly chlorinated

The required water flow rate for your whole home filter is higher than your water softener’s output flow rate.

Water Softeners Go First When:

Water is clear of high levels of sediment, chlorine, or iron

The water flow rate necessary to properly backwash your water softener is higher than your hole home filter’s output flow rate.

Don’t be afraid to ask for help from a local plumber or call your water filter or water softener’s manufacturer for assistance when making this decision.

If you do not currently have a good water softener or a quality whole home filter and are interested in having one, then be sure to check out our helpful buying guides for these important water treatment devices.

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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.

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