How to Bypass a Whole House Water Filter

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Installing a whole house water filter is an efficient way to get clean water.

If you have one installed at your home, you may wonder about the science behind turning it off.

Filtered water is excellent for cooking, drinking, and general use in your home. Besides, it increases the life of certain appliances that utilize water.

However, this doesn’t indicate you have to use filtered water outside your home. Filtered water might not be ideal for your pool and garden. Here’s when bypass valves come in handy – and not only then.

We’ll uncover more on the topic below!

Key Takeaways

These are the steps to bypass a whole house water filter:

  1. Select the ideal installation location.
  2. Pre-assemble all the parts.
  3. Close the water main.
  4. Put a mark on the pipe and cut it as close to the main shutoff valve as possible.
  5. Install the bypass before installing the filter system.
  6. Turn on the water and check for leaks.

What Is a Whole House Water Filter Bypass?

A whole house water filter bypass lets you divert the water around your filtration system. Simply put, it’s a small setup that allows you to turn off your water filter without disrupting water flow to your home.

So, when you turn off your whole house filtration system, the water flow doesn’t stop. Instead, you get continue using unfiltered water.

How to use a bypass? In depends on the bypass in question. With a 3-valve bypass, all you need to do is turn the lever position of the involved valves. This will “bypass” your filtration system until you turn the valves back to their previous position.

Big Blue Whole House Water Filter

Why Use a Bypass?

Whether you’re on city water or well water, you can be exposed to thousands of different contaminants.

A whole house water filter can eliminate these from your water supply and give you access to clean H2O. For this reason alone, most households prefer installing an efficient water treatment system.

But why use a whole house water filter bypass?

Easier Maintenance and Repairs

Anyone using filtered water knows water filters require proper maintenance – for instance a cartridge-based water filter needs regular replacements – to keep them up and running.

Here’s when a bypass come into play.

If you do not have an external bypass and no internal filter bypass either, you’d need to shut off the water supply to your entire home (inside and outside), in order to service the filter, repair it, or send it away for that purpose.

What’s more, if you’d need to order a specific part that broke, you would be without filtered water for days or even weeks! How terrible is that?

It may also be that parts of your whole house water filter need a professional overhaul. You take out the parts, send them to the company, the experts renew and then send them back to you.

This whole process can take days if not weeks since it’s not an overnight process.

So, instead of staying without water for this long, you can simply bypass your water filter system.

No Interruption of Water Flow

You do not require filtered water for yard work. So, bypassing your filter is the best option to give your system a break.

Besides, it doesn’t interrupt the filtered water flow inside your home – for drinking, cooking, bathing – during that time which is another plus.

Additionally, when you’re not using your whole house water filter aimlessly, bypassing outside taps limits filtered water usage and makes your system last longer.

Restricting water usage simply means increasing your filter’s life.

Bypass vs Installing a New Water Line

You may have considered the option of installing a new raw water line instead of using a bypass. We’ll explain why this is not an ideal alternative.

First, a bypass is cheaper compared to a new water line. Second, it requires less time and little DIY work.

On the flip side, a new water line is not a simple do-it-yourself job. You would need professional help for that purpose. So, labor and required material will automatically add up to the price. If you’re on a tight budget, we recommend the former option; it’s cheaper, easier, and works great, too.

How Does a Whole House Water Filter Bypass Work?

A bypass valve lets you direct water around a water filter. So, when required, you can shut off water to the filter and use unfiltered water instead.

This not only puts less pressure on the filter elements, it also works in your favor.

For instance, when sending away the parts of your filtration system for repair, you’ll still have access to water, although unfiltered, but water nonetheless. Without a bypass, you’d need to remove your water filtration system entirely, patch your pipes, and reinstall the filter after getting its parts repaired.

A proper bypass is typically made of three ball valves. Generally, the center valve of the unit is closed, whereas the left and right valves are open. To bypass, you’d need to do the exact opposite: Open the center valve and close the left and right valves. Although bypasses work without left and right valves, having both allows isolation of filters from the house plumbing when needed.

Installation: How to Bypass a Whole House Water Filter

A few whole house water filtration systems come with built-in secondary bypass valves. Others include kits with extra parts, and some even give instructions on setting up a bypass. The latter would require you to purchase additional materials, however.

Not sure how to get started? No worries!

We’ll explain everything you need to understand for installing a whole house water filter bypass. By the way, you do not need to be an expert for this; basic plumbing knowledge and DIY skills will do.


Before you begin, you need to decide about the type of bypass you want to install. Typically, the best alternative to built-in bypass valves is to build your own 3-way valve using existing pipes in your house.

Yes, this requires some extra work, but it’s worth it!

Start by collecting the right tools and supplies. You need to select the pipe material with which you’ll connect your existing pipeline. Copper, PEX, and CPVC are a few common materials.

Once you’ve decided on the pipe material, you have to choose the fitting type and material.

A few soldered connections require additional steps to fit, while solderless connections are the easiest to hook up. With some, all you have to do is push them onto the pipe, and you’re done!

ball valve and other plumbing tools and supplies

Tools and Parts List

We’ll share a few general tools and guidelines below. Note that this list varies depending on your system and the type of filter bypass you choose to install.

  • Valves
  • Fittings
  • Hacksaw
  • Sandpaper
  • Solder
  • Torch
  • Flux
  • Reaming tool
  • Additional pipe

Installation Instructions

Follow the instructions below to get started!

Select the Location

Select an appropriate location for your whole house water filter bypass. If you’ve installed your water filter already, this is the location to choose obviously.

Pre-Assemble All the Parts

Like a seasoned chef who gathers all the ingredients before cooking, make sure you pre-assemble all the parts before starting the actual installation process. Discovering a missing part in the middle of the work can be pretty annoying.

Put a Mark on the Pipes

A popular phrase goes like this, “Measure twice, cut once.

So, to eliminate the chance of inaccuracies, it’s better to mark your pipes to avoid trouble later on.

Though valves vary in length, the product specifications include information about precise measurements.

Shut Down the Water Supply

This sounds like a rather obvious step, but it’s pretty essential.

Besides, the whole installation process will take 1-2 hours, and perhaps you do not want to run out of water – especially if you have other people at home. So make sure you have enough water for drinking or bathroom use before you continue.

Prepare Your Existing Pipes

Preparing your existing pipes means cleaning them. This is primarily important for copper pipes. So, before you cut into them, make sure you clean them thoroughly.

Cut It

Usually, you want to cut your pipe close to the main shutoff valve. However, this isn’t a fixed rule. If available, it’s best to follow your filter’s manufacturer instructions to cut the existing pipe. Also, keep a bucket at hand to collect extra water.

Your manufacturer will walk you through the right steps to cut the pipe. It will also ensure you remove the exact pipe length necessary for proper fitting.

You can use a reaming tool or sandpaper to clean the pipe edges and remove dirt and debris. Leftover dirt can corrode pipes years later, and above all, contribute to leakages.

Connect the Valves and Turn on the Water

Put a nut and compression ring on both sides of your existing pipe. Once done, adjust the valve and secure the nuts.

Repeat the same procedure for the other valves, and you’re good to go.

Once you’ve connected all valves, turn the water back on and check your work for leaks.

If you have any questions about how to bypass a whole house water filter please don’t hesitate to leave a comment below!

About the Author Gene Fitzgerald

Gene Fitzgerald is one of the founders of BOS and currently head of content creation. She has 8+ years of experience as a water treatment specialist under her belt making her our senior scientist. Outside of BOS, Gene loves reading books on philosophy & social issues, making music, and hiking.
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Leave a Comment:

John says August 2, 2023

Was there a diagram? My thoughts was to put a T -connector prior to entering the sediment filter. Add a shutoff valve into the sediment filter and at the exhaust of the bypass. On the other side of the filter T into the exhaust of the Filter. The filter should be one way so no valves needed on exhaust side. That way normally the bypass is closed and filter is open. to bypass close the entry into the filter and open the bypass.

    Gene says August 3, 2023

    Hi John,
    Sounds good. However, I would recommend installing a shut-off valve on the outlet side, as well. That’s because even when you close the entry side for maintenance, water can still flow back towards the filter when you open the filter housings.

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