Tutorial: How to Change a Whole House Water Filter

Author: Jason Hollow - Published: 2021/05/14 - Updated: 2022/11/08

Disclaimer: This page may contain affiliate links. If you buy a product or service through an affiliate link, we may earn a commission but at no additional cost to you. You can view our full affiliate disclosure here.

Like any water filter, whole house water filters need to be changed after a while.

Considering that these systems are rather large, removing the old and installing the new filter cartridge is more complicated than servicing a point-of-use water filter – you need to turn off the main water supply to begin with.

The good news: This sounds quite complicated but it doesn’t have to be. As long as you’re handy with tools you don’t even need to hire a professional.

All steps required are outlined below.

So, let’s discuss how to change a whole house water filter!


These are the steps for changing a whole house water filter:

  1. Shut off the water supply and remove pressure from the system.
  2. Unscrew the filter housing and remove it, then detach the old filter cartridge.
  3. To clean the filter housing, you can use a brush with household bleach or soapy water.
  4. Make sure to lubricate the O-rings and check that they are seated correctly. Replace them if they are not in good condition anymore.
  5. Put back the filter housing with a new cartridge inside.
  6. Turn the water supply on slowly together with the nearby faucets and check for leaks.

What Is a Whole House Water Filter?

Whole house water filters are also called POE or point-of-entry water filters. That’s because they filter the water at the point of entry, meaning immediately after it enters your home. This has the benefit that all the water gets filtered whereas a point-of-use water filter only provides filtered water for a single tap, faucet, shower head, and the like.

With filtered water flowing through your entire home you don’t need to worry about which tap you use to fill your water glass – provided that you’ve installed a whole house water filter capable of supplying potable drinking water.

And not only that; a powerful house water filter can also protect pipes and home appliances by removing aggressive chemicals, heavy metals like iron[1], and sediment.

Replacement Tutorial: How to Change a Whole House Water Filter

How to Change a Whole House Water Filter Thumbnail

When it comes to changing a whole house water filter we need to differentiate between cartridge-based systems and those using one or more large filter media tanks.

The instructions below can be used for changing whole house water filter cartridges.

Systems that consist of large tanks filled with granular filter media are a different story. Usually, they last for many years before they require replacement. When the time has come, you either need to dispose of the entire tank or replace the filter media inside.

With that said, let’s dive into how to change a whole house water filter using filter cartridges!

But remember: Every water filter system is different, so you might need to alter or skip a few steps or complete additional tasks which we didn’t cover. This is why we recommend you to check your product manual before proceeding.

Step 1: Preparation – What You Need

Collecting all the tools and supplies you need before you get started can save you from potential disaster. Plus, it can save you a lot of time. Here’s what you need:

  • Filter housing wrench or strap wrench – A housing wrench is the go-to tool to use when opening a filter housing. If you don’t have one or don’t know where yours is, go looking for it. For filter housings that are stuck you sometimes need a strap wrench.
  • New filter cartridge or cartridges – The easiest way is to buy an exact replica of your old filter cartridge. But you can also switch between brands or install a different filter cartridge altogether as long as everything is standard-sized.
  • Replacement O-ring for each filter cartridge – You may need to replace one or more O-rings for each new filter you install. The O-rings ensure that no water leaks from the system, but they tend to wear out pretty quickly. Some manufacturers provide a set of O-rings with each filter cartridge.
  • Food-grade silicone grease – Silicone grease should be used to lubricate any old or new O-ring. Simply put, it provides an extra layer of protection and helps to prevent leakages.
  • Plumber’s tape – This one is optional, because some manufacturers explicitly advise against using plumber’s tape on their filter housing threads. However, in many cases it’s the best measure for getting a good seal.
  • Large bucket – A large bucket should be placed underneath your whole house water filter system to keep the floor dry. Also, it’s ideal to store the old filter cartridge in for the time being.
  • Second bucket with bleach solution – You want to think about cleaning the filter housings with mild household bleach to kill potential germs that may have accumulated over time.
  • Old towel – An old towel or rag for wiping things down.

Step 2: Turning Off the Water Supply & Releasing Pressure

Once you’re all set and ready to get started, first, turn off the water supply. There are different ways you can do this. There may be a shut-off valve right before your whole house water filter. Or you may need to go outside and turn off the water supply there.

If you can, bypass your whole house water filter so that the water supply to your home doesn’t get interrupted. If you don’t have a bypass installed, however, don’t worry. The whole process shouldn’t take too long anyways.

Water is turned off? Then you need to flush any remaining water in the water line. You can do so by opening the nearest outlets. They should be on the first floor.

Alternatively, if you have a shut-off valve both before and after your whole house water filtration system you can also turn them off and press the pressure release button on your filter (in case there is one).

Step 3: Opening the Filter Housing

Place the bucket underneath before you open the first filter housing – there still may be some water left.

Next, press and hold a red button on the filter head if there is one. This is to release pressure which makes it much easier to remove the filter housing.

Use the filter wrench or strap wrench to loosen the filter housing. You need to turn counterclockwise. Go slowly especially when unscrewing the filter housing because it’ll still be full of water. Also, don’t underestimate the weight of filter housing + filter cartridge + water. If you’re working with a big blue whole house filter you better use both hands!

If the filter housing doesn’t open and you fear of breaking it, you can use a rubber mallet to gently tap on the housing wrench. Don’t worry, it’ll open eventually.

Step 4: Removing the Old Filter & Cleaning the Filter Housing

dirty filter cartridge

Now you can take the old filter cartridge out of its housing. Pour any remaining water into your bucket.

We don’t really need to pay attention to the old filter, but you should carefully inspect the filter housing from the inside and outside. Can you see any cracks? How does the threading look?

What’s more, you want to remove any dirt from the side and bottom of the housing. Wipe it out with a clean rag and also consider sanitizing it with household bleach. Any unscented bleach should be just fine (rinse carefully!). Of course, you can also use warm water and soap for basic cleaning.

Step 5: Inspecting the O-Ring

Step 5 is all about O-rings. You need to inspect them and make sure they’re still in excellent shape. O-rings help to prevent leaks so you better look closely.

If you see any wear and tear it’s best to replace an O-ring. They’re not overly expensive and usually come with the filter cartridge.

Old or new, always lubricate O-rings with silicone grease. It’s your water supply we’re talking about so obviously you want to use food-grade silicone grease. Simply rub a light coating onto the O-ring using your fingers.

Lastly, make sure the O-ring is properly positioned and sits tight.

Step 6: Installing a New Filter Cartridge

At this point you can insert a new filter cartridge into the filter housing – make sure it’s centered – and screw it back on.

By the way, don’t use any wrench to tighten the filter housing. Most manufacturers recommend to hand tighten. This will also make it much easier to open the housing at the next filter replacement.

Step 7: Turning the Water Supply Back on

The final step is to turn the water supply back on, slowly. Going really slow allows you to simultaneously check for leaks.

If there indeed is water running from where the filter housing connects to the filter cap or any other place, turn the water supply off once more until the error is fixed.

You should also prime the new filter(s) as per manufacturer instructions before using the water.

How Often to Replace a Whole House Water Filter

How often you need to change your whole house water filter is not that easy to answer. It depends on several factors including

  • Your water conditions – City or well water, heavy metal content, sediment levels, how many hard water minerals are present, etc.[2]
  • Your water usage
  • The filter type
  • The size and capacity of the filter cartridge as rated by the manufacturer

Generally speaking, a whole house water filter cartridge lasts one to six months on average.

Fortunately, there are signs that tell you when it’s time for a new filter, such as:

  • You notice a drop in water pressure/flow rate
  • You sense bad water taste or smell
  • You see cloudiness or discoloration

trickling faucet

Besides, you can learn from experience. For example, if the old filter cartridge was all clogged up when you replaced it after 6 months, try replacing the new filter a little sooner.

Why You Need to Change

Some people may be wondering why they need to change their water filter in the first place. Well, it’s pretty simple: Any water filter can only remove a certain amount of contamination before it has reached its filtration capacity.

A carbon filter may have adsorbed so many chemicals that all its surface pores are full. Or a sediment filter may be clogged with sand and rust.

As a consequence, an old filter cannot remove any more contaminants from your water which means that it’s like not using a water filter at all. This may affect your drinking water quality, and your entire plumbing system including your water heater and other appliances as discussed before.

Another reason to change a (whole house) water filter in due time is to prevent bacteria and other disease-causing germs from accumulating in the inside.


You’ve learned how to change the cartridge of your whole house water filter. Most important is to turn off the water supply and flush out any remaining water before you get started.

Depending on your individual filter, the necessary steps include opening the filter housing, removing the old filter and replacing it with a new one, cleaning the filter housing, inspecting the O-ring, and screwing the filter housing back on.

How often you need to do this depends on your filter type and several other factors. One thing is for certain, though, every water filter cartridges needs to be replaced from time to time in order to guarantee effective filtration  and prevent germs from growing inside the filter.

Further Reading


Meet Jason Hollow

Jason Hollow Jason is the founder of Water Masterz and head of content creation. After six years in the industry, he has tremendous knowledge and first-hand experience on all things related to water treatment.

His credo: Not a single American should have to drink unhealthy water at home.

Leave a Reply

Your email address will not be published. Required fields are marked *

4 × 3 =