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Home » Water Filtration Systems » DIY Whole House Water Filter Guide

DIY Whole House Water Filter Guide

By: Craig Smith
Last Updated:
DIY Whole House Water Filter Guide

If you have been searching for a whole house water filter, you may have been put off a little by the high cost of some of these systems. 

While they are very efficient when it comes to purifying water, you simply may not be able to or want to make the expenditure it takes to purchase one.

This is also why some prefer to make their own DIY whole house filter system.

It’s not a bad idea if you do some thorough water testing followed up by some research to help you determine what type of water filtration components your DIY water filter system must have.

For those that are interested in doing this, I am here to help. I have used my many years of water filtration experience to come up with a DIY whole house water filter guide for you.

A guide that will help you design a DIY whole house water filtration system (also known as whole-home or point of entry water filters) that will improve the purity of your home’s water and help you do that in a budget-friendly way.     

Why Build Your Own Whole House Water Filter?


There are some nice advantages to building a homemade water filter and a few disadvantages too. Here are the main ones:


  • If DIY water filters are done right, you can get the same performance at substantial savings over purchasing a complete whole-home water filtration system from a company.
  • You will significantly increase your water filtration knowledge; that’s because you have to do extensive research to build your DIY whole house filter properly.
  • You may be better able to tailor your homemade whole house filtration system to the specific contaminants in your water that are of the most concern to you.
  • Installing your own DIY home water filtration system lets you take extra time to ensure that all of your connections are leak-free and valves are placed exactly where they have the most value to you.
  • The materials needed to connect your purchased water filtration components are usually readily available in hardware, plumbing, or home improvement stores.
  • You can construct your whole-house filter in a way where you can add more components at a later time to further improve upon its ability to remove harmful contaminants.


  • The research it takes to design your DIY whole house filter and then installing it can be very time-consuming.
  • Your new system has not been rigorously tested and proven to work such as store-bought point of entry water filters are.
  • You need to periodically test your system to guarantee it’s impactful and this testing can be costly.     

I will also tell you that you should be plumbing savvy and willing to take the time and effort to thoroughly test your home’s water supply and then build a whole-home filtration system based on that information.

If not, then you are much better off just paying a little more to buy a quality whole house water filter to purify your water supply.

If you shop around enough, you should eventually come across a point of entry water filtration system that fits your budget or can be bought on a very affordable installment plan.     

How To Make Your Own Diy Whole House Water Filter

Here are the steps that you will need to undertake to properly install an impactful DIY point of entry water filtration system:        

Get Your Water Tested

Some of the tips that I will give you regarding DIY whole-house water filtration systems will be more like suggestions but this is not one of them. This is one of the most critical steps in the entire DIY whole-house filter building process.

Why is testing your water supply so important? I will start by saying that store-bought whole home filters tend to target a very wide range of impurities that are commonly found in tap water. That’s why they are so expensive.

This means they may contain some components that do not apply to your home’s current water supply quality. An example of this is a manufacturer’s POE filtration system that has an iron filter in it.

If you have no iron in your household water supply, then you are buying this filtration system component for no reason.

By eliminating this filter component when designing your system, you have the opportunity to lessen the cost of your whole-house filter. That’s the main reason that people build point of entry water filtration systems themselves.

I will add that when testing your home’s water, you have to do extensive water testing to know what the most concerning impurities in your water are. Simple home test kits will not get the job done.

That’s why it’s best to purchase a quality laboratory test kit that you buy online and then send in a sample of your water to be analyzed. With these, they will test for a wide variety of tap water contaminants and the results that you get will be extremely accurate.

To do this water testing, I highly recommend the city and well water test kits made by a company called ‘Tap Score’. You just order them online, fill the water sample vials when the test kit arrives, and then send them to the company for analysis in the provided prepaid envelope.

A few days later, the results of the testing will show up in an email.

Next, review the results of the laboratory testing, determine which contaminants in your drinking water concern you.

Then build your whole house water filtration system using components that significantly reduce or eliminate the impurities in your water that you want to target for removal.

Tools You’ll Need

Not only will you need some basic plumbing knowledge to install your new DIY point of entry water filter but you will also need the proper tools, supplies, and pipe fittings to do the job.


  • Basic tool kit (assorted screwdrivers, hammer, tape measure, box knife, etc…)
  • Hacksaw
  • PVC saw
  • Adjustable wrenches (small & medium)
  • Small pipe wrench
  • Drill
  • Drill bits
  • Solder Iron (when connecting to metal piping


  • Bucket
  • Teflon tape
  • Solder
  • Pipe mounting brackets
  • PVC or copper piping
  • Assorted PVC or copper pipe fittings
  • PVC glue
  • Shut-off valves

System Components

Since you are designing your whole house water filtration system, you can do anything within reason to set it up. The object is to place different components that target the specific water impurities in your water that you want removed in the proper sequence.


This is usually done in at least 3-stages. Above is a photo of what a whole house water filter housing for your second and third stages will look like.

What are those filters that are most commonly used in simple 3-stage whole house water filters and what sequence do they go in on a POE system? They are usually as follows. 

  1. Sediment Pre-Filter       

You should never design your whole home filtration system without a sediment prefilter being placed first in line on the system. Sediment filters are designed to screen out large size particles from your incoming water.

Placing Sediment filters first so they can screen out larger water contaminants helps keep your other filter media from becoming clogged up too fast and this helps extend their useful life.

Typical sediment prefilters usually contain some type of mesh filter with a 40 to 50-micron pore size. This is a small enough pore size to remove larger solids like dirt, hair, rocks, and more. Use a ‘spin-down’ sediment filter for easy maintenance, especially if you have well water.

  1. Granular Activated Carbon (GAC) Filtration 

This impactful DIY whole house water filter system stage contains granular activated carbon (GAC) that will filter out some of the finer sediment particles in your incoming water that your sediment prefilter can’t catch. 

Install one of these that has a 20-micron pore size, that is a small enough pore size to also enhance the aesthetic effects of your drinking water (the removal of chlorine taste, odor, color).   

  1. CTO Activated Carbon Block Filtration 

This secondary whole-house carbon filter stage contains a popular filter media called coconut shell carbon (CTO). One of the advantages of using a filter with CTO is that it helps maintain a higher flow rate through your whole-home water filter.

I recommend using one of these that has a 5-micron pore size, which is enough to further enhance the aesthetic effects of your drinking water (chlorine removal) and will also filter out many harmful volatile organic contaminants (VOCs), pesticides, and other chemicals.

****Please Note****

Even though they make CTO activated carbon filters with as small a pore size as 1-micron, you want to stick to these recommended filter sizes.

That’s because the smaller the pore size on the carbon filtration stages that you place in sequence on your whole-home filtration system, the more you will reduce the water pressure in your home.

To supply an average size house with consistent good water pressure, you should have a flow rate through your DIY whole house water filtration system that is between 8 to 20 GPM. Using filters with the above-mentioned pore sizes should help you to be able to achieve that.

That’s why I recommend making the water quality that is distributed throughout your home by your new DIY whole-home filtration system to just be decent.

Then further enhance your water quality with a good under-sink filter, countertop filter, water pitcher, or another type of point of use water filter.

Setup Process Tips

Here are some important tips to keep in mind when it comes to installing a DIY whole-home filtration system.

  • Be sure to install bypass valves on your main water supply line. Bypass valves allow you to still use the water in your house when doing system maintenance or repairs.
  •  Install your whole-house filter system before your water heater to help protect its delicate heater element and its other parts that come into contact with water.
  •  Lay out your plumbing configuration on the floor to ensure that you can assemble it correctly before starting to glue or solder together plumbing pipes and fixtures.  
  • Never install a POE water filter outside
  • Be sure when you are putting together your new point of entry filter system that you leave enough room between components to work on them easily and so you can add more water treatment devices in the future as your home’s water situation calls for and your budget allows.
  • If your water is mostly large sediment-free, let your outside spigot water bypass the system because it then makes no sense to filter it.
  • Don’t over tighten plastic filter housings or you may crack them.
  • Thoroughly inspect the system for leaks once you first turn on the water and use your newly self-installed whole house water filtration system.

Worth noting is this setup process and the above-mentioned filter stages will only provide you with a minimal whole-house filtration system setup.

You can further treat your incoming well water using a water softener, bacteria-killing UV light device, KDF 55 filter media, and situation-specific water filters such as POE iron and whole-house fluoride filters.  

Summing Up the Feasibility of DIY Whole-Home Water Filtration Systems

As you now see there is a lot of flexibility when it comes to building your own whole home water filtration system. You can make it as simple or sophisticated as you want but the more sophisticated it is the higher the price will be.

If the price goes up too high, then you are probably better off taking advantage of more sophisticated store-bought whole house filters. DIY point of entry filtration system building is both doable and practical if done right but it can also be very tedious and time-consuming to get installed.

I would recommend keeping your new homemade whole home water filtration system simple and then combining it with a good reverse osmosis filter or small pore size carbon point of use water filtration device.

That way you will have better than average quality water running throughout your entire home and you will have even higher quality water to drink after completing this DIY project.  

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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