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Home » Water Filtration Systems » How to Bypass a Whole House Water Filter

How to Bypass a Whole House Water Filter

By: Craig Smith
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How to Bypass a Whole House Water Filter

It may seem like it’s easy to install a whole house filter and in most cases that’s true if you have a little bit of plumbing knowledge.

But there are certain aspects to the installation of them that must be done right. One of those installation tasks is to install a well-designed and simple to activate bypass line.

Why is this important?

It’s because there are times when you still need water when your whole house filter is unavailable and other times when you need large amounts of water that does not require filtration.

That’s why here I will talk about how to bypass a whole house water filter along with what a water filter bypass system is and some examples of why they are a necessary part of any whole house filter installation.

What Is a Whole House Water Filter Bypass?

There are occasions when you want your home’s incoming water line that goes through your whole house filter (also known as point of entry and whole home filters) to divert around that water filtration system.

This is made possible using what’s known as a bypass valve setup. It’s a simple system that lets your incoming water come straight into your indoor and outdoor water taps without passing through your water filter.

A bypass setup needs to be installed whether you have a single tank style whole home filter (see photo below),


a point of entry water filtration setup that uses a series of individual filter cartridges (see below),


or any type of  special use whole home filter such as an iron filter

Why Use a Bypass?

Here are some of the main reasons that the installation of bypass system on your POE filter is so highly recommended by me and other water filtration professionals:

  • You will still be able to use unfiltered water in your house when performing maintenance on your POE water filtration system or that system is under repair.
  • There are times, such as when filling your swimming pool or watering your lawn, that using large amounts of unfiltered water is better than putting wear and tear on your water filter and its filtration media.
  • It’s much cheaper than installing a second water main line that essentially does the same thing as a filter bypass setup.
  • When used properly, it can significantly extend the life of your whole home filtration system and lengthen the time between needing to perform periodic maintenance.

How Does a Whole House Water Filter Bypass Work?

When installing your whole home filter, you do it in such a way that all your incoming water supply runs through it.

You install bypass valves (usually 3) on the system for those rare times you need to work on your point of entry water filter or require large amounts of water where there is no need to filter it.

All that’s required to activate a water filtration bypass setup is to open a single valve on a 3-valve setup and then close the other two.

It really can be made that simple to divert your incoming water around your point of entry (POE) water filter.

Installation: How to Bypass a Whole House Water Filter

Plumbing and water filtration professionals such as I am are not the only ones that feel having a bypass setup on any quality point of entry water filter is essential.

Some manufacturers also feel so strongly about having bypass valves on the system they even include them with the purchase of their whole house filter models.    

If your whole house filter does not come with a bypass setup, then you will have to install one yourself.

Here are the steps involved in doing that:

Step1: Read the Installation Manual

Your new whole house filter system should come with an installation manual. I highly recommend that you read that manual from cover to cover before trying to install bypass valves on it.

This serves two purposes:

  1. It makes you aware of what you need to complete the project and how to do it.
  2. Reading the manual may also alert you to the fact that you don’t have the knowledge to do this task and you need to hire a plumber to do it for you.  

Step 2: Gather the Tools You Will Need

For the purposes of this article, I will describe how to do the most common 3-valve bypass setup on your whole home filter (see photo below).


There really is no need to install a fancy or elaborate filter bypass system because you most likely will not be using it very often.

Here are the most used tools for the job. Keep in mind that these will probably not be the only tools and parts you need to complete the project. Much of that depends on the type of pipe you use and how complex you choose to make your new filter bypass system.

Necessary Tools for the Job

  • Valves
  • Pipe (I recommend at least 1” copper or PVC pipe)
  • Fittings
  • Hacksaw
  • Sandpaper
  • For PVC pipe: primer and glue
  • For copper pipe: Solder, Torch, Flux, Reaming tool

Step 3: Select the Placement Location of the Bypass Setup

If you have a basement or garage where your incoming water line comes into your home, those are the most likely places to set up your new whole house filter.  

Your bypass valve for that system can either be free standing or the pipes can be attached to a nearby wall.

Step 4: Pre-Assemble the Parts

I always like to lay out the parts for everything that I put together around my home and that would apply to my new bypass valve setup.

By laying it out beforehand on the floor, it gives me a better idea of how I want to build my new bypass valve and lets me know if I am missing any parts to do the job.

Your bypass valve setup when laid out on the floor should look very close to the 3-valve setup in the picture under Step 2.

Step 5: Shut off Your Incoming Water Supply

To be able to do this task successfully, you will first have to locate and shut off your incoming water line.

This is usually done by going outside and looking for an underground box that contains the main water line shutoff valve.

Step 6: Cut into Your Incoming Water Line

I like to take a permanent marker or marking crayon and mark the places on the incoming water line where I need to cut them out to install a system bypass valve. This helps avoid cut mistakes.

Before I cut into the pipes, I will also clean any dust, mold mildew, or other substances that will prevent me from making a good connection with the new piping I am about to add onto them.

Step 7: Install the Bypass Valve Setup

Now it’s time to assemble and attach the bypass valve setup that you have laid out on your floor to your incoming water line.

Think of it this way. You have built what is essentially a puzzle on the floor when you laid out your bypass valve assembly.

Now take the pieces of that puzzle and assemble them together one by one until you have your new bypass valve free standing on top of your POE filter or attached to the wall alongside of it.

I also advise you to take your time when putting valves, pipes, and connections together. That’s because it can be a difficult and painstaking process to have to take your new bypass setup back apart to fix a leak.

Step 8: Test Your New Bypass Valve Setup

No plumbing job is ever complete until you have tested it to make sure there are no leaks.

So now, go back outside and turn back on your main water line.

Then go back into your garage or basement to make sure that none of the components on your new bypass setup are leaking.

Here you will also observe if the valves on the system are working as intended.  

You should now have a system in place that is able to divert the water around your whole home filter for those rare occasions that you will need to do that.

Be Sure to Install a Bypass Setup on Your New POE Filter

I have stated more than once that I believe installing a filter bypass setup on any new whole home filter that you buy is essential.

That covers you when you must do maintenance on your point of entry filter, if you have a problem with it and need a repair, and for those times it’s not necessary to stress your POE filter by having large amounts of water run through it.  

The steps mentioned above for the installation process are straightforward and only require a small amount of plumbing ability.

If you can’t do this job yourself, it’s important enough to the workings of the system that you should hire a professional plumber or handyman to install a bypass valve on the system for you. 

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.

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