How to Change Filters in Your Whole House Water Filter

A whole house water filter system saves you the trouble of installing individual filters for each faucet and shower head in your home. It’s a one-time deal, which means you certainly won’t have to keep track of many gallons of water passing through each single filter. Now you only need to keep track of a single main filter, and you can do that easily enough with your water meter. After all, every drop of water that goes into your home from the water supply line goes through the whole house water filter system. 

A good whole house water filter doesn’t really need a lot of maintenance. This is actually one of its main advantages. Still, the time will come when you need to replace the filter in the system. Filters aren’t eternal; after a certain number of gallons of water passing through a filter, you’ll need to replace it. Considering how much water a family can use up in a month, it may take only 3 to 6 months before it’s time for a replacement filter. 

The good news is that this isn’t as complicated as you might think. In fact, if you do the initial installation right in the first place you shouldn’t have too much trouble at all. Here are the steps you need to take: 

Turn the Water Off

Find the inlet side of the pre-filter as well as the outlet side. You’ll then need to turn off the water at both sides. Usually, these valves have a red color which you just turn. 

Relieve the Pressure

Look over the top of the pre-filter housing. Do you see that button right in the middle? That’s the red pressure release button. Press that button so you relieve the pressure from the pre-filter. 

Unscrew the Housing

For this step, you may need a prefilter wrench to loosen the housing. When you bought your whole house water filter system and you already planned to change the filters yourself, you should have bought this tool as well. It may be very difficult for you to unscrew the housing without this tool. 

At this point, a lot of homeowners may lose the O-ring from the housing when they’re changing the filter. This is found on the inside lip of the canister. So keep track of this so you don’t lose it. If you do lose it, you may have to buy a replacement O-ring. In fact, you may want to get a replacement O-ring before you start changing the filter, just to play it safe. 

Remove the Filter

Once the housing has been unscrewed, you can just take out the filter. That’s the white cylindrical thing inside. 

Clean the Filter Housing

At this point, you may as well take advantage of the exposed filter housing and clean the inside of the housing. A small amount of bleach will do, though when you rinse it afterwards you should make sure you get all the bleach out. A rust-remover will also work. 

Put In the New Filter

Once the inside of the housing is clean, you can then put in the new replacement filter. Hopefully you bought this replacement already, before you started to unscrew the filter housing. If you haven’t bought one yet, head on out to your local home center to see if they have one.

It’s best to have this ready, because you may just end up buying your replacement online. That will take a longer time, so you risk having unfiltered water at home while you wait if you don’t buy one in advance.

Check the O-ring

This should be in place, before you put the housing back on. Check it over and see to it that it’s clean of any debris. Feel it up, and if it feels dry you may have to apply a small film of non petroleum base to it. This will make sure get a good seal. 

Screw the Housing Back in Place

This time, when you screw the housing back onto the cap, don’t use the prefilter wrench. In fact, don’t use any tool at all. Instead, just tighten it up by hand. That will be enough to ensure a good seal. You don’t want to over tighten this, as this can just result in leaks. 

Test It

Turn the water back on by turning back the valves. Check it over for a few minutes to see if there are any leaks. Once you’re sure you’re leak-free, your job’s done and you can now go back to enjoying your super-clean filtered water. If you do notice a leak, turn off the water again and seal the leak by reconnecting the housing and by applying some non petroleum base to the O-ring. 


As you may have noticed, this isn’t exactly a complicated proves. You just have to be careful for each step and you need the prefilter wrench and the replacement filter ready. 

How easy this process really is will depend on how you installed (or how your plumber installed) the whole system in the first place. If this was done right, you’ll have less trouble. In addition, some whole house water filter systems are designed for easier filter replacement. You may take note of this when you buy the filter system in the first place. 

It’s best if you note when you put in a new filter, and you then keep track of how much water your family uses. You should also note if the water pressure for the whole house goes down, as that may be a sign that your filter is clogged and needs to be replaced. Just follow each step we’ve listed, and you won’t even need to call the plumber. 

Just remember to be careful about the O-rings, because quite a few people end up losing track of this during this procedure. Without the O-ring, you won’t get a good seal. You may even have to replace it just to be on the safe side, if it’s not working as it should.

Leave a Comment