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Home » Water Filtration Systems » How to Choose a Whole House Water Filter

How to Choose a Whole House Water Filter

By: Craig Smith
Last Updated:
How to Choose a Whole House Water Filter

If you have decided that a whole-house water filter is definitely worth having, then take that one step further and make sure that you get one that adequately fits your water purification needs.

There are so many whole-house water filters (also called point of entry water filters) choices in the home marketplace, it’s very easy to purchase one that does not meet your tap water purification and other requirements.

Take it from me, someone who spent 26-years as a swimming pool water filtration professional, you don’t want to make a mistake when spending money on a whole-house water filter. It’s too important an apparatus to get wrong when buying one.

You can avoid potential dissatisfaction with your POE water filtration system purchase by following the steps below that describe in detail how to choose a whole house water filter.

Other Helpful Resources:

1. Get Your Water Tested to Determine Contaminants

It only stands to reason that if you don’t know what contaminants are in your home’s tap water, then you won’t know how to get them out. That’s what makes getting your household water tested before making a whole-house water filter buying decision a good choice.

There are several ways in which you can go about doing this. If you have a swimming pool supply store near you, then chances are that they will have a water testing setup. Water purification system sellers and municipal water testing options may also be available near you.

I think the easiest way to get your water tested is by ordering a self-water test kit online. At the very minimum, You want a test kit like the Varify 17 in 1 Premium Drinking Water Test Kit pictured below that detects the most commonly found household water contaminants.

To be able to fine-tune your whole-house water filter purchase even more, there are pricier tests such as the Safe Home Premium Water Quality Test Kit that we recommended in our best water test kit review. With this one, you take a water sample and then send it to a lab where it will be tested for hundreds of impurities.

2. Decide on The Right Type of Whole House Filter for Your Contaminants


You are now only on step 2 and you have already done the most important task when it comes to determining what point of entry (POE) water filtration system you will purchase.

Now it’s time to take your water test results and find a system that will remove or reduce most, if not all, of the impurities found in your tap water.

If you are on a municipal water supply, chances are you will have found such contaminants after testing as the following:

  • Chlorine
  • Fluoride
  • Calcium
  • Pesticides
  • Fertilizers
  • Heavy metals
  • Petrochemicals
  • Dioxins
  • Radioactive Materials

Fluoride and chlorine are often present in city water because they are one of the best ways to kill the microorganisms that are commonly found in the freshwater sources that supply your municipal water.

The other impurities on the list result from most city water systems seldomly running the water that they treat through advanced filtration devices.

If your home’s water is supplied by a well, according to the EPA, these are the most concerning impurities that you likely came across when testing your tap water:

  • Microorganisms Including Bacteria, Viruses, and Parasites
  • Fluoride
  • Nitrates
  • Organic chemicals
  • Heavy Metals
  • Radionuclides

Well water is much more of a wild card than city water when it comes to the impurities found in it. That’s because almost anything that can go into solution or travel as a solid in groundwater can end up in your well.

So, if you have well water supplying your home’s water needs, then you will most likely need a specific well water whole house filter compared to if you have municipal water you can get a standard whole house water filter.

The bottom line here is, whatever contaminants that you found in your tap water that are a concern to you, these are the impurities that your new POE water filter must significantly reduce or remove.

So make sure to check that the filter you are purchasing removes those contaminants.

3. Know the Flow Rate of Your Appliances


This is an often-overlooked aspect of whole-house water filtration systems when people are shopping for them. That’s not good because some appliances around your home such as tankless water heaters need a certain amount of water flow going through them to work.

These figures are often expressed in Gallons per Minute (GPM).

Here are some recommended flow rates for different appliances:

  • Dishwasher: 2 to 4 GPM
  • Tankless water heater: 3 to 5 GPM
  • Washing machine: 3 to 4 GPM

Not only can the water flow rate after your whole-house water filter impact your appliances, but it can cause other inconveniences as well. This includes low water pressure coming from showerheads and kitchen faucets that trickle.

These are some other recommended water flow rates to keep in mind:

  • Kitchen faucet: 2 to 3 GPM
  • Showerheads: 1.5 to 2.5 GPM (regulated by law to not be higher in most places)

When looking to buy a reverse POE water filtration device, make sure that you will have adequate water flow on the supply side of the device to run your appliances and to comfortably use faucets, spigots, and showerheads.

4. Determine What Size is Best

Now that you know some of the required water flow rates for your appliances and common water exit points, you need to also be aware of what’s known as a service flow rate.

This is your POE water flow rate in gallons per minute being large enough to handle the amount of water that flows through it each day.

Here are some general service flow rate guidelines to follow:

Number of Bathrooms1 to 2
2 to 4
5 to 6
7 to 8
9 to 10
1 to 25 GPM7 GPM10 GPM10 GPM14 GPM
2 to 37 GPM10 GPM12 GPM12 GPM16 GPM
3 to 4N/A12 GPM14 GPM16 GPM18 GPM
4 to 5N/AN/A16 GPM18 GPM20 GPM

Service flow information on a whole-house water filter may be presented in the product information or it can be obtained by calling a manufacturer’s customer service center.

5. Ensure the Quality of The Filter Will Last

Although I think that you will agree with me that whole-house water filters are a worthy investment with all of the benefits that you will get from them, they are by no means a piece of equipment that you want to have to replace regularly.

Here are some ways to avoid having that happen:

Brand reputability

The price of that generic brand POE water filter online or on that store shelf may be appealing but will it meet your home water purification needs?

You will never have to worry about this if you purchase a brand-name whole house water filtration system from a reputable manufacturer.

Testing & Certifications

Checking out what 3rd party testing and certifications have been attached to a whole-house water filter is also a very good idea. This will give you a good idea of how well a POE water filtration device removes contaminants and if it’s constructed using safe materials.

The most respected testing certifications come from such independent water filtration equipment testing groups as NSF, ANSI, and WQA.

Examples of these certifications include:

  • NSF/ANSI/CAN 61-2020: Safe Drinking Water System Components
  • NSF/ANSI 42: Water Aesthetic Effects Certification (chlorine taste, odor, color)
  • NSF/ANSI 58: Reverse Osmosis Filtration Device Standards
  • NSF/ANSI 401: Emerging Compounds/Incidental Contaminants

Look for these trademarks that indicate 3rd part quality testing has taken place on a whole house water filtration system.

Type of Filter & Replacements

The media that’s found inside of whole-house water filters does not last forever. So, at some point, you will have to change the system’s filters out.

So, you should be aware of such things as what type of replaceable filters your POE system has on it, how often they need to be replaced, and how difficult it is to change them out.

When the time comes for replacement check out our whole house filter cartridge review.

6. Choose a Good Model That Fits Your Budget

It goes without saying that if you want the ultimate whole house water purification system, then you would go with a large reverse osmosis POE water filtration device. It also goes without saying that this will set you back as much as $10,000 to buy one so it’s not realistic for most people.

I realize this is a dollar amount that most certainly is not in everyone’s budget range. It assuredly was not in mine. That’s why I chose to use an activated carbon-based whole house water filter working in conjunction with a point of use reverse osmosis drinking water system.

That combination gives me nicely enhanced water everywhere in my home and some outstanding quality drinking water.

So, you don’t have to be rich to significantly enhance your home’s tap water quality. In most cases, you can come up with a more than adequate whole house filter that meets your needs for under $1000.

You definitely can match your whole-house water purification needs with your allocated budget if you take your time looking before making a purchase.

Take Advantage of These Whole-House Water Filter Buying Steps

I am a big fan of whole-house water filtration systems. That’s because I believe that no matter what type of water supply that you have, some impurities that may harm you or your family’s health will find their way into your tap water.

POE filters will at least partially address many of those concerns.

You also have to keep in mind that there is no perfect whole-house water filtration solution (unless maybe you spend a huge amount of money), so look for one that eliminates the major worries that you have with your household water.

If you follow the above-mentioned point of entry water filtration buying steps, you stand the best chance of getting a whole-house water filter that more than adequately covers your overall home water purification needs.

It will also do that without impacting water flow and other household water-related concerns. You simply cannot go wrong investing your time into finding the right POE water filtration system.

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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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