The Best Whole-House Water Filters in 2021 – Buyer’s Guide & Reviews

In most homes, a quality under-sink filter should suffice to solve your water safety concerns. But if you also want clean water for your baths, showers, dishwasher, and washing machine, a complete whole-house water filtration system is what you need.

The best whole-house water filters can remove troublesome sediment, dust, and chemicals from the source water  before they reach your house’s main inlet, keeping water throughout the household clear, crisp, and odor-free.

Given its size and capacity, a whole-house filter can be a big investment. This article aims to guide you through finding the right one for your home. We’ll also review some popular models to save you time on your search.

How to Choose a Good Water Filter for the Home

Determine the Target of Filtration

Before buying a whole-house filter, you should know which water contaminants you want to get rid of. The potential contaminants depend on the water’s source and the pipes it travels through.

Tap Water

Common contaminants in tap water include, but are not limited to:

• Disinfectants: chlorine, chloramine, fluoride
• Disinfection byproducts: chloroform, bromodichloromethane, dibromochloromethane, etc.
• Heavy metals: arsenic, lead, chromium
• Radioactive elements: uranium, radium, strontium-90
• Carcinogenic Volatile Organic Compounds (VOCs): benzene, 1,2,3-trichloropropane, 1,4-dioxane
• Hormones: estrogen

If you’re using tap water, a good resource for reliable information is the Safe Drinking Water Information System Reports developed by the Environmental Protection Agency (EPA). Their website allows you to find reports specifically about tap water quality. 

Similar information can also be found on the Environmental Working Group’s Tap Water Database. Note that EWG’s criteria are stricter than federal legal standards. It’s not uncommon to find reports of excessive amounts of harmful chemicals in your state-approved tap water. The database is a good source for reference, but it’s up to you which standards you’ll accept for your water.

Water quality may also be affected by the pipe system in your home. For the most accurate analysis, you may want to take a sample of your water and have it tested in an accredited laboratory. 

Well Water

In well water, the variety of potential contaminants is wider. The types and levels of contamination also vary from home to home. These can include:

• Sediment
• Microorganisms: bacteria, viruses, and other parasites
• Iron
• Nitrates and nitrites
• Heavy metals: arsenic, antimony, cadmium, chromium, copper, lead, selenium
• Organic chemicals
• Radionuclides: uranium and radium
• Fluoride
• Others

If you’re using water from a private well, it’s crucial to send a sample to a laboratory for a full analysis of its bacteriological and chemical composition. 

Apart from sediment, one of the most easily detectable contaminants in well water is iron. Although the metal is not likely to pose a health risk, it can cause a metallic taste and smell in the water at concentrations as low as 0.3 milligrams per liter. Water with high concentrations of iron also appears reddish in color and may leave rust residue in the pipes and stains in your sink and on ceramic dishes.

What Filtration Media Do You Need?

Once you confirm what’s in your home’s water, the next step is to find a filtration system that can handle it. 

It’s best to call a water treatment expert to discuss the options. But to get a basic idea, here’s a graph that compares the effectiveness of popular water filtration media against common water contaminants.

Note that the information may not be 100 percent accurate. The actual effectiveness depends on many factors such as the quality of the filter and source water, as well as the duration of contact between them.

Is a Whole-House Water Filter System Enough?

You may find that a simple cartridge system is often enough to handle non-health related contaminants such as chlorine or sulfur. 

If you have hard water, you may also want to install a water softener along with the filter. This will help protect your pipes and water appliances against mineral buildup. 

Whole-house cartridge filters and softeners, however, cannot filter out lead, arsenic, hormones, or other health-damaging elements. If such contaminants are present in your home water, it’s a good idea to install a strong reverse osmosis system under the sink so you can have safe water for drinking and cooking.

Alternatively, a whole-house reverse osmosis system alone may be able to give you pure water for all purposes. However, it’s probably more a luxury than a necessity. 

Look for Certifications

An indication of high quality in a water treatment system is an NSF/ANSI-standard certification. NSF/ANSI certifications guarantee the filter’s material safety and structural integrity, as well as its performance in reducing contaminants. The key ones to look for are:

• NSF/ANSI Standard 42: aesthetic, non-health-related contaminants, such as chlorine 
• NSF/ANSI Standard 44: hard mineral reduction, barium reduction, and radium 226/228 reduction, among others
• NSF/ANSI Standard 53 (mostly for water softeners): health-related contaminants such as lead, cysts, and VOCs 
• NSF/ANSI Standard 55 (for UV systems): pathogenic bacteria, viruses, Cryptosporidium, Giardia (Class A), or non-health-related microorganisms (Class B)
• NSF/ANSI Standard 58 (for reverse osmosis systems): total dissolved solids (TDS) and additional contaminants such as cysts, barium, copper, arsenic, and lead

You should keep in mind that these standards testify to different claims. “NSF-certified” can be an ambiguous term. If you’re concerned about a specific contaminant, make sure to get a filter certified to remove that exact one. 

Note that some whole-house filters contain certified components, but they may not be certified as a whole system. One reason is that unlike tap filters or shower filters, which are point-of-use appliances, whole-house filters are installed at the point of entry. After filtration, the water continues to move through pipes to taps and devices, potentially picking up contaminants along the way. As such, they can’t guarantee the water coming out of your tap is clean.

In the US, the leading agency accredited by ANSI to test and certify water systems to NSF/ANSI standards is the Water Quality Association (WQA). There are other independent agencies that offer similar services; you can check on ANSI’s website to see if they’re an accredited partner.

How Much Does a Whole-House Filter Cost?

A whole-house water filter can cost anywhere from a few hundred to several thousand dollars, depending on its capacity, construction, certification, and brand. The price for a cartridge filter can be between $700 and $1200 or potentially even higher if it’s a heavy-duty system.

If you bundle it with a softener or UV purifier, expect to double the cost.

Installation by a plumber may set you back hundreds of dollars more. Simpler systems may allow you to save on this by doing it yourself. Most whole-house water filters come assembled, the only work left is to connect them to your water line and in some cases, to electricity. 

Check carefully before you do, though — some companies require installation by a certified professional or they may void the warranty.

Another thing to take into account when buying a filtration system is the replacement cost. You may want to opt for a system that doesn’t require changing cartridges too frequently. A good timeframe is six months to one year. 

If your water contains more sediment, consider adding a coarse pre-filter to help prolong the life of the system. This small investment may save you more money in the long run.

Check the Warranty Terms and Conditions

Most manufacturers offer years-long warranties for their whole-house water filtration systems, but the duration and specific terms vary vastly between brands. HomeMaster, for example, promises free replacement or repair over a 2-year period, while Aquasana extends it to 10 years. 

It goes without saying that the manufacturer will void the warranty if the water filter is not installed as instructed. In some cases, even proper installation by a non-professional will result in the warranty being voided. This is something you want to check carefully before bringing a system home.

Whole-House vs. Reverse Osmosis Water Filtration Systems

Home water filtration systems are divided into several different categories. 

In terms of point-of-installation, there are point-of-entry (whole-house filters) and point-of-use (under-sink, countertop, tap-mounted) filters. If you sort by method of filtration, we have polypropylene sediment filters, carbon filters, reverse osmosis filters, etc. You can also break them down by stage of filtration, giving you pre-filters, main filters, and post-filters.

Installed at the point of entry, where water first enters the house, a whole-house filtration system is responsible for the treatment of a large amount of water. This water later goes to your heater, sinks, bathrooms, taps, toilets, dishwasher, washing machine, and all other water appliances for domestic use. This type of system must do its job with minimal reduction in flow rate and water waste.

There is a lot of overlap between different filter categories, and sometimes a reverse osmosis filter can be a whole-house filter. However, this is not usually the case, hence the colloquial distinction between the two.

Cartridge vs. Reverse Osmosis Whole-House Filters

A typical whole-house water filtration system features one or a series of polypropylene sediment filters, carbon filters, and sometimes, especially if you’re using well water, a UV lamp. It’s usually a cartridge system. The filters can also be combined with a water softener or descaler if there are large amounts of “hard” minerals in the source water. 

See more: The 5 Best Water Softeners to deal with Hard Water

Most cartridge whole-house systems are not designed to remove heavy metals or harmful chemicals, so water quality depends largely on source water quality.

A cartridge system wastes very little or no water. It may cause reduction in water pressure, but as long as you change the filter when it’s due, this will not be significant enough to affect your daily activities.

A reverse osmosis system, also called a backwash system, includes a reverse osmosis (RO) membrane, polypropylene sediment filter, carbon filter, and post-filter, and often a UV lamp as well. 

RO systems can handle health-damaging contaminants, but water takes a lot of time to go through the membrane. The bottom line is that water pressure gets reduced significantly. Therefore, you will see a storage tank for filtered water. Treated water is most likely drinkable immediately.

The Problem With RO Filters

The reason they’re not the most common choice for treating water for the whole house despite their superior effectiveness is that RO systems aren’t very efficient. You would need a very large system, including large reserve tanks, to make enough water for daily household use. 

RO water filters are also known for wasting a lot of water in their rinsing process — up to four times the amount of clean water they can produce. 

The costs of the systems themselves, installation and maintenance costs, and the prospect of an increased water bill discourage most people from choosing large reverse osmosis setups. That’s reasonable, though, considering that most people don’t need drinkable water for their clothes or toilet bowls. 

Reverse osmosis systems are therefore more often installed at the point of use for drinking and cooking water, in conjunction with a simpler whole-house filtration system.

Read more: The 13 Best Water Filters of 2021 – Buyer’s Guide & Reviews

Best Whole-House Water Filters to Buy in 2021

To save you time, we’ve done the research and worked out a list of the whole-house filters that are most capable of addressing common water problems. Read on for the detailed reviews.

Here are our picks for the Best Whole-house Water Filters to buy in 2021:

1. Springwell CF1 Whole House Water Filter System – Best to Buy in 2021
2. Aquasana EQ-1000 Whole House Filter System – Best Runner-up
3. Home Master HMF3SDGFEC 3-Stage System – Best for Well Water
4. Home Master HMF2SMGCC 2-Stage System – Best for Tap Water
5. 3M Aqua-Pure Whole House Filtration System – Best Inline Water Filter
6. Culligan WH-HD200-C System + Filter – Best for Value

Top-rated Whole House Water Filters Comparison Chart

System	Target	Target	Filter Life*	Warranty
Springwell CF1 (Editor's Choice)	Sediment Taste and odor Disinfectants (chlorine, chloramine) Bacteria and viruses (ad-on) Water hardness (ad-on)	1,000,000 gallons	Pre-filter: 6 - 9 months Main filter: 6 years up	Lifetime against defects
Aquasana EQ-1000	Sediment Taste and odor Disinfectants (chlorine, chloramine) Bacteria and viruses  Water hardness	1,000,000 gallons	Pre-filter: 2 months Main filter: 10 years	10 year limited
Home Master HMF3SDGFEC	Sediment Taste and odor Disinfectants (chlorine, chloramine) Iron and manganese	100,000 gallons	1 year	2 years limited
Home Master HMF2SMGCC	Sediment Taste and odor Disinfectants (chlorine, chloramine) Iron and manganese	95,000 gallons	1 year	2 years limited
Aqua-Pure	Sediment Taste and odor Disinfectants (chlorine, chloramine) Sediment Taste and odor Disinfectants (chlorine, chloramine)	100,000 gallons	1 year	25 years limited warranty for head 1 year limited warranty for cartridge
Culligan WH-HD200-C	Sediment Taste and odor Disinfectants (chlorine, chloramine)	10,000 gallons	2 - 3 months	3 years limited

*Calculated for a family of three with average amount of water used per person per day equaling 100 gallon.

1. Springwell CF1 – Best to Buy in 2021

The Springwell water filtration system comes with a filter that removes chlorine and some heavy metals while also improving the taste and smell of your water. The filter has a life of up to one million gallons, and you can get it shipped to your door for free. You also get the reassurance that comes with a 6-month money-back guarantee.

Activflo Filtration

This system uses Springwell’s unique ActivFlo filtration technology with four filtration materials in two separate canisters. It not only removes chlorine but also eliminates a wide variety of other harmful contaminants.

The first canister features a mixture of KDF (Kinetic Degradation Fluxion) and coconut-shell activated carbon. 

KDF is an NSF-certified media in which a copper-zinc media works through an oxidation process to handle a wide variety of impurities from water, especially chlorine and hydrogen sulfide. Coconut-shell carbon, meanwhile, has a great deal of surface area which can trap and neutralize chlorine, pesticides, herbicides, and any unusual odors and tastes. 

What distinguishes this filter from others is an additional flex bed. This media eliminates channeling and maximizes contact time between the water and the filtration media. This way, there is more time for the filter to do its job and remove any traces of impurities.

The second canister houses the sediment filter. This one cleans any sand, clay, soil, and other debris from the water that is smaller than 5 microns (about 1/15 the diameter of a human hair).

Note that the increased contact time is still not enough for the filter to be effective against heavy metals, even though the KDF may reduce them to some degree. Water experts from Springwell recommend the LCR-1R filter for guaranteed results if you’re dealing with lead. The brand also has a separate system for water from a private well.

Flexible Add-Ons

The Springwell system comes in various sizes, accommodating households with anywhere from one to seven bathrooms (and everything in-between). This variety makes it easier to find something that suits you and your home. 

If you’re worried about microbial contamination, there’s an option to add a UV-light purifier to the system. It will take care of E.coli, Cryptosporidium, and Giardia lamblia, among other bacteria and viruses with a success rate of more than 99%.

Springwell also offers whole-house water filter and softener combos that pair this filter with a salt-based or salt-free water softener. If you’re dealing with hard water and on the look out for a complete system that targets both harmful substances and high levels of minerals, these combos will serve you well. They’re also less expensive when bundled together.

Installation and Maintenance

It’s best to find a professional to do the job for you, but if you’re the DIY type, the system is easy to set up. Springwell made a video that helps guide you through the preparation and installation step by step. 

Once installed, the filters run by themselves unless you install the UV light, which needs electricity. You can pretty much forget about the system (apart from the sediment filter that needs replacement every 6 to 9 months), and get on with your life.

Warranty and Service

This Springwell whole-house water filtration system is covered by a lifetime warranty against defects. The brand guarantees the removal of chlorine and chloramine below minimum detection levels for the first 6 years or for one million gallons, whichever comes first. It’s also probably the only one in the industry that offers a 6-month money-back guarantee. 

The brand offers free FedEx delivery and an option to pay in installments.

2. Aquasana Eq-1000 Whole-House Water Filter and Softener – Best Runner-up

This system consists of pre- and post-filters, a salt-free softener, and a UV chamber that all arrive in one complete, well-rounded system to solve every single possible problem with your water. To top that off, the company offers a 10-year limited warranty.

A Strong, Long-Lasting Filter

The EQ-1000 filter can process an incredibly large amount of water: 1 million gallons. If you are a family of three with an average use of 100 gallons per person per day, it will easily last more than 9 years.

Even with the cost of the pre-filter (which must be changed every 2 months), post-filter and the electricity for UV light added, it’s still a good bang for your buck.

Inside the main filter are copper-zinc media, minerals, and activated carbon. These all work to reduce not only chlorine but also water-soluble heavy metals, pesticides, herbicides, bacteria, and algae.

While the filter itself is not NSF-certified, it uses the same components and media as the Aquasana EQ600, which is certified against NSF/ANSI standards to remove more than 96.9% of chlorine in the water. This should be more than sufficient to bring your home’s water down to your desired aesthetic level.

Most users report immediate improvements in the taste and smell of their home water after installation of the Aquasana system. 

Salt-Free Softener

If you hate having minerals building up in your pipeline, sinks, and bathroom tiles but also don’t want more salt in your diet, a salt-free softener is your best bet. This Aquasana system conveniently includes one.

Its saltless softener, or to be technical, its descaler, has proven effective in reducing the building up of scale and corrosion in pipe systems. It does so while requiring minimal maintenance for itself.

Note, however, that while it can alter the structure of the minerals to protect the pipeline, the descaler does not remove them outright. If you are concerned about excessive calcium and magnesium in your water, you may need to add or replace it with other appliances.

Destroys 99.99% of Microorganisms

Municipal water is treated with filters and chemicals that kill most of the microorganisms living in it. However, there are chlorine-resistant cysts like Cryptosporidium and Giardia which may pose a health risk. Well water, meanwhile, travels to your house with all the worms, germs, and viruses in it. 

A good filter can at best remove some of the bigger sediments and organisms, but a UV light purifier is needed to bring the water to the desired level of safety.

After the filtration process, the water will be free of most visible contaminants and will have become clear. It is now that the Aquasana UV light purifier comes into effect. It kills more than 99% of viruses and bacteria, including e. Coli.

This is why this Aquasana system is as good for well water as it is for tap water.

3. Home Master HMF3SDGFEC – Best Whole House Water Filter for Well Water

The Home Master HMF3SDGFEC features a filter that tackles iron, manganese, and sulfur — the most common contaminants in well water — and improves water aesthetics immediately. With NSF-certified components, the system is not cheap, but the quality makes it worth the price.

The well-water filtration system boasts three stages of water treatment.

The first stage consists of four layers of filtration that can keep out sediments as small as 1 micron across. To give you an idea, a human red blood cell is about 5-8 microns, while our hair is about 70 microns across. The finest traces of sand, rust, dirt, and other particles are removed in this stage. 

The second stage features an iron reduction filter that can remove 95% of iron, manganese, and hydrogen sulfide at a combined load of 3ppm. This stage is what will save  your pipes, water heater, dishwasher, and washing machine from developing rust. It will also keep the orange stains and rings off your sink, toilet bowl, and ceramic ware.

Note, however, that it can only be effective under specific water conditions. It’s a good idea to get your water tested and check the detailed product description before you buy the system.

After the iron filter, the water is treated with granular activated coconut-shell carbon (GAC). Famous for its numerous pores and a large surface area, the carbon can trap significant amounts of pesticides, herbicides, hydrogen sulfide, and other undesirable chemicals, further refining the water. Most users report a clear difference in water quality as soon as the system starts running in their home.

Installation and Maintenance

The Home Master HMF3SDGFEC system comes pre-assembled and is not overly difficult to install. However, the cartridges are bulky and heavy, so make sure you’ve got the space and strength for it.

Included in the package are a steel mounting bracket, bolts, housing wrench, and instructions. Most DIY users have to buy non-petroleum-based silicone to seal the o-rings on the canisters, and if you have a ¾-inch water line, you’re going to need reducers to connect it to the 1-inch ports.

The Home Master well-water filtration system can treat 95,000 gallons of water in its lifetime. That’s roughly one year for a family of three. The filter replacement interval may vary depending on the contaminant load. If the water in your home contains too much sediment, installing a coarse pre-filter may help lengthen the life of this system.

4. Home Master HMF2SMGCC – Best for Tap Water with Chlorine/Chloramine

The Home Master HMF2SMGCC comes with components that are NSF-certified to improve water aesthetics. It’s the perfect choice when you’re looking to reduce the smell of disinfectants in your home water.

Certified to Filter Chlorine and Chloramine

The HMF2SMGCC filtration system runs on two simple filter cartridges.

Water will first go through a multi-gradient depth sediment filter. During this stage, sediment as small as 1 micron will be removed. If your water has a lot of sediment, you may want to install a coarse pre-filter before this stage to prevent clogging and reduced pressure. 

The second cartridge contains 3 pounds of KDF85 granular activated catalytic carbon. KDF is famous for its ability to reduce water-soluble lead, mercury, nickel, chromium, and other dissolved metals. The filter, however, is not certified for this.

Its NSF certification is for the significant reduction in the amount of chlorine and chloramine from the water. It also improves the smell and taste of your home water by reducing sulfur, iron, and other aesthetics-related contaminants.

With a simple design, this system won’t cause a change in your water bill or flow. At their sizes, the filters can process a large amount at a time. They also come with 1-inch ports and have no problem giving you 10 gallons of clean water per minute.

Easy Installation

The Home Master HMF2SMGCC is probably one of the easiest water filtration systems to install.

It comes right out of the package with the filters fully assembled, and has a steel mounting bracket with bolts, housing wrench, and a direct, easy-to-understand instruction manual. If you’re the DIY type, you probably won’t need to call a plumber. Just keep in mind that it can be a bit bulky and heavy.

With a capacity of 95,000 gallons, this filtration system can easily last a year for a family of three. It goes without saying that mileage may vary, and you may have to replace the filters more or less often depending on the actual water usage in your home.

Note: If your tap water doesn’t contain chloramine, consider the Home Master HMF2SDGC, a slightly more affordable version of this system.

5. Aqua-Pure – Best Inline Filtration System

Simple, compact, and easy to install, the 3M Aqua-Pure is the best filter for families who find a multi-stage filtration system too much to handle. It’s NSF-42-certified too for its effectiveness against non-health-related contaminants.

Two Filters In One

In most other systems, the sediment and carbon filters stay in two separate cartridges. The Aqua-Pure combines the two filters in one housing, secured and connected to your pipe by a 304 stainless steel head. This design is meant to simplify storage, installation, and maintenance. 

It works like a charm on typical tap water with disinfectants and minimal sediment. The filter can easily last one whole year, providing you 100,000 gallons of clean, crisp, odor-free water. Most users report an immediate and remarkable improvement in their home water quality.

When there is more sediment in the source water or the pipe system, however, the design has been reported to backfire. The 5-micron pores can get clogged quickly, preventing water flow to and through the carbon block. This causes water pressure to drop significantly, in some cases, to the point the user has to bypass the system altogether. This may happen 5-6 months after installation or even sooner depending on the source water quality. 

The solution is to install a pre-filter to catch bigger sediments in the water. This increases the total cost slightly, but if you’re using well water or if your home pipes are old, it will be worth it as the pre-filter can improve the system’s effectiveness and significantly prolong the life of the AquaPure.

Installation and Maintenance

As mentioned, the Aqua-Pure comes in a simple design with a non-corrosive stainless steel head and one single filter cartridge. A handy DIYer would be able to set it up using basic plumbing tools. 

Replacement is a piece of cake with its quick-change, no-contact cartridge: you can do it in less than two minutes with no equipment. The cartridge isn’t cheap, but at least you won’t have to pay for a professional to change it.

6. Culligan WH-HD200-C System + Filter – Best Budget Whole House Filter

Certified for NSF/ANSI Standards 42 and 372, it’s hard to find a system in this price range that can compare in effectiveness and efficiency to this Culligan model.

A Complete System

This combo features the Culligan WH-HD200-C filtration system and the RFC-BBSA premium heavy-duty replacement cartridge. It’s designed to handle sediment, dirt, extra fine sand, silt, rust, and the taste and smell of chlorine, and you will find from the reviews that most users are happy with the results. 

The system and filter combo can stand alone to produce clean, crisp, odorless water for the whole house. You can take it a step further by combining it with coarse pre-filters and/or carbon post-filters to maximize effectiveness and extend its life. This, however, is not always necessary.

Installation and Maintenance

The system comes with everything you need to get it going: a mounting bracket, housing wrench, filter life indicator, built-in shut-off, bypass, and pressure relief valve. Installation is simple and may be done yourself.

On paper, the filter can last six months or 10,000 gallons, whichever comes first. Of course, its actual life will depend on the quality of the source water. You may have to change it earlier if water pressure becomes low or if you see sediment buildup through the system’s clear housing. There’s a filter change timer on the system, so you don’t have to worry about it.

Unlike with the Aqua-Pure, replacing this Culligan system can be a little more complicated. You will have to remove the cartridge and clean the housing before putting in a new filter core. On the other hand, because it has a metal bracket, the system is a lot more stable, making it easier to handle.

Frequently Asked Questions

Do I Need a Whole-House Water Filter?

If you’re using well water or are living in an old house with outdated plumbing, you run a high risk of exposure to harmful contaminants. You most likely need a whole-house filtration system for dirt, rust, sediment, parasites, and potentially heavy metals and chemicals.

Tap water in Europe and North America’s big cities is pre-processed and usually safe for consumption. A whole-house filter is often not a necessity unless you’re sensitive to disinfectants such as chlorine, chloramine, or fluoride. That said, there have been incidents like the Flint water crisis where health-damaging contaminants are found in supposedly clean tap water.

To be on the safe side, get your home water tested to identify any potential problems and go from there.

Are Whole-House Water Filters Worth It?

A good whole-house filter can make a significant impact on your home water quality in terms of health, aesthetics, or both. Noticeable benefits may include:

• Clear water that tastes and smells better. This may get the children and pets to drink more.
• Improved skin and hair conditions (acne, dandruff, or other conditions that can be caused by polluted water).
• A better shower/bath experience as there is less sediment and fewer chemical contaminants that irritate the skin
• Fewer stains and less residue in your water appliances (dishwasher, heater, kettle, washing machine, etc.).
• Potential improvement to your digestion and overall physical health if you have conditions caused by drinking contaminated water.

Can I Drink the Water Filtered with a Whole House Filtration System?

Most whole-house filters only deal with aesthetic problems in the water (taste, smell, clearness), though a few are certified to filter out health-damaging contaminants such as lead, arsenic, and mercury. It’s best to get the water tested at a certified lab after filtration to make sure it’s safe for drinking.