Whole House Water Filter Installation – Where & How to Install a System

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Imagine this: Turn on the tap, any tap, and the water is fresh and free from unpleasant taste and odors. Even the water in the shower doesn’t smell like chlorine! This is easily accomplished by installing a whole house water filter. Whole house water filters are also known as point-of-entry systems because they are installed directly into the main water line.

To do this, a little plumbing know how is required. Most people opt to call in a plumber to get the job done, but that will set you back an extra few hundred dollars. If you’re reasonably handy and patient, it’s possible to learn to set up the system yourself with a little knowledge under your belt. (And a few tools, of course!)

Installation Location is Everything

Needless to say, you can’t stick a water filter just anywhere and hope it works. Ideally, whole house water filtration systems should be installed near where your home’s main water line enters the building. That way, you’ll have filtered water all over the house! There are a few more things to consider before you start. Choose a location that:

  1. Is easily accessible. Like any water filter, whole house systems require regular maintenance, like installing replacement filters. If you can’t easily access the system, you’ll be less likely to stick to a consistent maintenance schedule, leading to premature breakdown of your shiny new water filter. No, thanks! Pick a spot that’s easy to get to, and your water filter will thank you.
  2. Is upstream of the water heater and close to the primary shut-off valve. The reason for this is simple. If water is filtered before it runs through the water heater, the heater itself will be processing purified water free from damaging sediment and scale. Your water heater (and all hot-water appliances) will last longer, and the installation is just as easy.
  3. Is installed after the pressure tank if your home runs on well water.
  4. Is preferably inside. It’s technically possible to install a water filter outside, but whole house water filters are best kept in the garage or basement instead for maximum lifespan.

Should a POE water filter be installed before or after a water softener? It depends.

If your home runs on city water, install the water filter before the water softener to preemptively remove chlorine that would otherwise wear out the ion exchange media. Another reason to install before the water softener is to prevent pressure issues.

Those running on well water should probably install a whole house water filter after the water softener, to avoid reduced flow during backwash cycles. Well water doesn’t naturally contain any chlorine, so unless you add it yourself, there won’t be any around to damage the softening resin.

Whole House Water Filter Installation Diagram

whole house water filter installation diagram
Courtesy of best-osmosis-systems.com

What You Need in Your Toolbox

It’s highly unlikely that a whole house water filter would come with all of the tools and parts required for installation. The exact parts and tools will vary slightly depending on the model, but here’s a general list:


  • Drill and drill bits
  • Adjustable wrenches
  • Hacksaw or pipe cutter
  • Screwdrivers
  • Bucket
  • Teflon tape
  • Soldering materials (extra)


  • Your new filtration system, of course
  • Tubing
  • Mounting brackets (for some water filters only)
  • Fittings
  • Shut-off valves
  • Pressure gauges (extra)
  • Bypass valves (extra)

The Installation Process

Got everything? Let’s get started! Lucky for you, the installation process is virtually the same regardless of which whole house water filter you purchase, so this guide should work for everyone. It will take some time, so set aside a few hours up to a full afternoon for your DIY project, depending on your level of plumbing experience. With a little patience, your new whole home water filter will be up and running in no time.

How to Install a Whole House Water Filter

Always remember to read the manual through all the way before you begin installation. It’s wise to check your city plumbing codes, too, to make sure your setup complies. Always call the manufacturer if you have any questions. Read through this entire guide first as well so you know what’s coming at each step of the way. For extra help, this video gives you a good visual of what the process should look like.

  1. Before you do anything, shut off the main water supply.
  2. Next, drain the water left in your home’s plumbing system by opening all the faucets and fixtures. This step will also release water pressure.
  3. Use the hacksaw or pipe cutter to cut out a section of the main water line at your chosen location. The section needs to be big enough to fit your new filter system, so measure carefully before you cut. Keep a bucket handy as well in case some leftover water spills out.

cutting main water line with hacksaw

  1. Sand the sharp edges of the pipes and remove any built up sediment or scale from within the pipes.
  2. Add shut-off valves to make maintaining the water filtration system a whole lot easier. For the most convenient combination, install a valve on each side. You can also install a bypass to allow water usage even when the system is being serviced. At this stage of installation, keep all the valves closed.
  3. The best way to know if it’s time to change filters is by checking input and output water pressure. We recommend installing one pressure gauge near both shut-off valves to easily tell when the filters need to be replaced.
  4. Consider screwing a piece of plywood to the wall behind where the water filter system will sit for easier mounting.
  5. Now comes the tricky part: installing the actual system. To start, check to be sure the in and out ports are facing the correct way. If your pipes don’t fit into the ports, you can use adaptors to make it work. Don’t ever overtighten plastic fittings or they may crack. Just apply Teflon tape on threaded ends to reduce the risk of leakage.
  6. Choose from push fittings or soldering. If you use push fittings, you don’t have to bother with soldering at all. If you like to solder things, clean the ends of the pipes before you begin and be sure not to get the heat close to plastic parts that may melt.
  7. Does the whole house water filter come with housings? Rinse them out first with warm water, grease the O-rings, and be sure they aren’t loose after you install them.
  8. Ready? Time to test your work! Just turn the water back on.
  9. Keep the bypass valve closed, but open all the others.
  10. Any leaks? If there are, don’t stress. Just tighten fittings and water filter housings as needed to strengthen seals.
  11. If you’re the proud owner of an old home, there’s a chance your house relies on water pipes to ground your electrical system. To keep the system grounded, attach a copper-wired jumper cable with grounding clamps from one side of the water filter to the other. Easy peasy!
  12. Let the faucets run for a few minutes to flush the system of any air bubbles and debris that entered the pipes during installation.
  13. Read the instructions that come with the water filter to be sure the filtration media is activated properly.
  14. After the pressure is back to normal, turn off all the taps and call it a day!

A note on the bypass valve: Normally, this valve will stay closed. The only time you’ll need to open it is when the water filtration system needs to be serviced. At that point, just open the bypass valve and close the regular valves so your home will still have access to water during filter maintenance.

You’ve got this!

If you were intimidated to begin with, don’t be! Installing a whole house water filter on your own is totally doable with the proper tools. To avoid rendering your home waterless for a day or two, make sure you have ALL the parts and tools you need before you start cutting up the main water line. As long as you do, the process should go smoothly.

If you get stuck during the installation process, call the manufacturer’s customer service line and they should be able to walk you through it. Also, there is no shame in hiring a professional to do the setup for you. Sure, it will add to the cost, but better safe than sorry. Alternatively, you can always share a comment or question below, and we’ll be happy to get you back on track!

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