How to Choose the Best Whole-House Filter for You

Considering a whole-house filtration system but not sure where to start? This article is a great introduction to whole-home filters.

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30% of Earth's water comes from underground. Even if you use a public water source, it's possible your supplier's source is groundwater. In fact, about 145 million people in the US get their water from groundwater.

Groundwater is an excellent source of freshwater, but toxins can sometimes transfer from the soil to the water. While it's not a common occurrence, people do get sick from drinking tap water even in America.

Isn't it time you protected yourself and your family? If you've ever considered a new filtration system for your home, we're here to help you find it.

Whole-House Water Filters Defined

Whole-house water filters connect to your home's point of entry (POE), so the water throughout your entire home gets filtered. They're also called POE filters for that same reason. For clarity, a nickname for under-sink or countertop water filters is point of use (POU) filters as they only work where they're installed.

Like POU filters, whole-home water filters purify your water of contaminants. But, unlike POU filters, they do it for every water-bearing appliance in your home. Not just sinks and showers, but washing machines, toilets, and dishwashers too.

The only thing a POE doesn't typically filter is the water you use for your lawn. This is because they're most often installed after the main line splits into "house" and "yard" lines.

What Do You Need to Eliminate?

Just as not all water contains the same contaminants, not all filters eliminate the same contaminants. This makes it important for you to understand both what's in your water and what your new filter can eliminate

Some of these toxic items include:

Coliform bacterias that cause recurring gastrointestinal sicknesses
Radon, usually found in well water
Unacceptable pH levels, lead, rust, and copper from old plumbing
Hard water caused by higher mineral content in the water
Manganese and iron from water softeners
Sulfur (and hydrogen sulfide gas) that produce a rotten-egg smell or taste
Dies and detergents resulting in colored, cloudy, or frothy water
Nitrates and pesticides from extensive agriculture work
Chloride, barium, sodium, and strontium from nearby gas drilling
Volatile organic compounds (VOC) causing fuel smells
Chloride and sodium producing salty-tasting water

Evaluating Your Water Supply

You don't need a water filter that clears out everything so much as you need one that removes what you have. For this reason, it's important to test your water supply before buying any type of filter.

Remember, it's not enough to know what's in your water supply, you must also find out the amounts. If not, you may end up with a POE filter that isn't powerful enough to purify your supply.

The way you find out what's in your water supply depends on whether you use a private or public source.

Private Water Source

If you get water from a private source, like a well, you alone are responsible for ensuring its quality. That may sound a little scary, but it isn't all that bad. It simply means you should test your water more often than someone who uses public water does, even if you do use a filter.

Never had your water tested? Don't worry it's easy to do and you've got options. In most cases, your county/local health department can help you test for bacteria and nitrates. Use the directory of local health departments to help you find one in your area.

If your health department can't help you with the testing, you can turn to a private lab testing facility. They'll either send you a testing kit with detailed instructions or dispatch a technician to gather samples and run tests. Call the Safe Drinking Water Hotline at 1-800-426-4791 or click this link to find a lab near you.

You can also test the water yourself. There are plenty of water-testing kits available, and for the most part, they're accurate. That said, some do have trouble detecting things like pH levels and fluoride with accuracy.

Public Water Source

For public water sources, you can contact your local supplier for a Water Quality Index (WQI) or a Consumer Confidence Report (CCR). Both documents should list known contaminants in the supply. Most suppliers must test their water on an annual basis.

Public supplies can have toxins within a certain margin and still be legally acceptable. For example, according to the Environmental Working Group, the Greenville Water System in South Carolina has had six contaminants that exceed their health guidelines. Incidents like this strengthen the argument for a whole-home filter.

What's Your Flow Rate?

In reference to plumbing, flow rate is the number of gallons of water that can flow through a pipe in a single minute. It's measured in gallons per minute or GPM.

There are two types of flow rate: service flow rate and peak flow rate. The service flow rate is a measure of water flow during normal use. Peak flow rate is the flow rate if every water source in your home is in use.

A pipe's diameter is the primary factor in determining its flow rate. The larger a pipe is, the more water can flow through at a time. Smaller pipes limit water flow.

Why is Flow Rate Important?

There are several reasons to know the flow rate of your plumbing before buying a whole-house water filter.

If the flow rate of your home is lower than that of the filter you buy, it could cause damage to your plumbing. If it's higher, it could cause the water coming out of your faucets to sputter as the pipes fill with air.

Your home's plumbing is not the only thing flow rate affects. If water flows through your filtration system too quickly, the water won't come out clean. This is because the water needs time to absorb into the granular-activated carbon in the filter. It can also cause your filter cartridges to expire quicker.

A filter rated for 1 to 2 GPM more than your home's flow rate is what you're shooting for.

Calculating Flow Rate

Calculate the service flow rate of your plumbing by adding the flow rates of fixtures and appliances. To determine the flow rates, grab a five-gallon bucket and see how many gallons you can fill in one minute. This may be tougher for appliances than faucets and fixtures, but give it your best shot.

Add up the flow rates of your fixtures and appliances that run more than ten minutes to get your service flow rate. Calculate the peak flow rate by adding the flow rates of all fixtures and appliances in your home.

Typical flow rates for fixtures and appliances are:

Sink faucets: 2 to 3 GPM
Toilets: 2 to 3 GPM
Showers: 1.5 to 3.0 GPM
Dishwashers: 2 to 4 GPM
Washing Machines: 3 to 5 GPM

What is a Port and What Size Port Do You Need?

The port is the connection between your home's main water line and the filtration system. Standard port sizes are 3/4" and 1".

As a general rule, it's best to use filters with a 1" port even if you have a 3/4" pipe. This helps to keep the water from bottlenecking, which results in lower water pressure

Get a Filter That's NSF-Certified

When you buy a water filter, make sure it's certified by the National Sanitation Foundation (NSF). Manufacturers who make certified filters get held to a higher standard than normal industry guidelines. You know that filters approved by the NSF hold up to the claims they make on their packaging about what contaminants they can remove.

When checking for NSF certifications, look for both the standard name (i.e. NSF/ANSI 42) and a claim for what it does.

For example, a filter certified with an NSF/ANSI 53 standard reduces water hardness. This type of filter uses a softener that replaces magnesium and calcium ions with potassium or sodium ions.

Here's a list of NSF standards for water filters and what they mean to help you in your research.