What Do ZeroWater Filters Remove from Drinking Water?

ZeroWater filters, by Culligan, have become increasingly popular in the highly competitive water filtration market. But even with all the marketing, it’s not immediately clear how effective ZeroWater filters are at removing various contaminants.

The next entry in our unbiased filter review series explores ZeroWater filters and which contaminants they are certified to reduce in your drinking water.

Table of Contents:

• How Do ZeroWater Filters Work?
• When Should I Consider a ZeroWater Filter? 
• What Are ZeroWater Filters Certified to Remove?
• What Are They NOT Certified to Remove?
• How Do I Know My ZeroWater Filter Is Working?
• What’s the Takeaway?

How Do ZeroWater Filters Work?

According to their website, ZeroWater filters consist of “five stages that combine multiple technologies to remove organic and inorganic contaminants in the water,” including activated carbon filtration and ion exchange technology.

ZeroWater’s filters come in three popular formats:

• Pitchers
• Countertop dispensers
• Faucet-mounted filters*

The ZeroWater 5-Stage Filter consists of a mesh filter screen to capture suspended solids, a foam distributor, granulated activated carbon to remove organic contaminants, ion exchange resin to target specific inorganic compounds, and an ultra-fine mesh screen for final filtration.

*Note: ZeroWater’s faucet-mounted ExtremeLife Faucet Mount system does not use the 5-stage filter system.

ZeroWater’s pitcher and countertop dispensers also feature the “Ready-Read,” an integrated TDS meter that displays a live reading of the total dissolved solids (TDS) of the water as it passes through the filter system.

• What Does TDS Tell You About Water Quality?
  Low TDS is often equated with better water quality, but that isn’t necessarily the case. Neither high nor low TDS is a sure indicator of water quality because it’s only one parameter among the many that contribute to overall quality. The vast majority of minerals measured by TDS are harmless.
  
  High TDS readings (>500 PPM) indicate that the water sample has a high dissolved mineral content, but a high TDS reading does not indicate the presence of any specific contaminants. A more comprehensive water test can reveal both your TDS level and what dissolved minerals, metals and other constituents are in your water.
  
  

ZeroWater Pitchers & Countertop Dispensers

Most of ZeroWater’s pitchers and water filtration dispensers use the same filtration technology—the 5-Stage Filter described above. These products come in a number of different sizes:

• 7, 10, and 12 cup pitchers
• 20, 22, 30, 32, and 52 cup countertop dispensers

ZeroWater also offers a 10-cup EcoFilter Pitcher featuring a plastic-free carbon filter designed to reduce chlorine. However, the EcoFilter is less effective at reducing chlorine compared to the 5-Stage Filter and is only certified to reduce chlorine, with no certification for other contaminants.

ZeroWater Faucet-mounted Filter

ZeroWater’s faucet filter is known as the ExtremeLife Filter System Faucet Mount. It features activated carbon fiber technology.

When Should I Consider a ZeroWater Filter System?

ZeroWater filters offer cost-effective, easy-to-use filtration systems certified to remove a variety of contaminants, but whether one of their filters is the best option for your home depends on your water's specific makeup—testing your water first is strongly recommended.

ZeroWater posts the performance certifications for their products on their website, which lists the contaminants each filter is certified to remove. If you’re concerned about contaminants that aren't listed in the certifications, you may want to investigate alternatives that fit your needs.

Going into the hunt for a filter system with the results of a water test already in hand allows you to better assess how effective each treatment system will be at meeting your needs.

How Cost Effective Are ZeroWater Filters?

ZeroWater replacement filters are more expensive than the standard filter options from industry titans Brita and PUR.

How Long Do ZeroWater Filters Last?

According to the ZeroWater website, you should replace the filter once the Ready-Read TDS meter (included with the system) reads 006 or higher. Depending on your water’s quality, this may range from 8 to 40 gallons of use.

Additionally, it’s recommended to change the filter if you notice any difference in the taste or smell of your water. For water particularly high in TDS, filters may require replacement as often as every two weeks to make sure it works properly. This is something to consider when evaluating the overall cost of the treatment system.

Is ZeroWater Filtration Right for Me?

It’s important to test your water first to ensure this filter is the right choice for your home. If your primary concerns involve contaminants like lead, chromium, mercury, and PFOA/PFOS, then the 5-stage filter could be a good choice. Make sure to review the certifications for each individual model since they vary.

What Are ZeroWater Filters Certified to Remove?

Below are the three ZeroWater filters we’ve covered, along with the NSF/ANSI standards they’re certified to meet and the specific contaminants they reduce.

ZeroWater EcoFilter - ZR-002ECO (NSF)

• NSF/ANSI 42: Chlorine, Taste and Odor

ZeroWater 5 Stage Filter - ZR-0xx (IAPMO)

• NSF/ANSI 42: Chlorine, Taste and Odor 
• NSF/ANSI 53: Lead, Mercury, PFOA, PFOS and Chromium

ZeroWater ExtremeLife Faucet Mount Filter - ZRFM-001 (WQA)

• NSF/ANSI 42: Chlorine, Nominal Particulates Class I*, Taste and Odor 
• NSF/ANSI 53: PFOA and PFOS 
• NSF/ANSI 401: Microplastics

*Includes particulates between 0.5 and 1 micron in size

What Are NSF, WQA, and IAPMO?

NSF, WQA and IAPMO are three different organizations that grant certifications to water treatment devices that meet standards for performance and safety.

Do ZeroWater Filters Remove Minerals?

Due to the presence of ion exchange technology, ZeroWater filters are likely to remove various minerals from water, though their performance data sheets do not specifically mention the removal of minerals.

When it comes to minerals like calcium, magnesium, sodium, and potassium, it’s important to note that most people get their recommended daily intake primarily from food. While water can be a source of these minerals, especially when it comes from areas with naturally high mineral concentrations, it's generally a less significant contributor compared to diet. Drinking water with low mineral content isn’t harmful, but it won’t supplement your intake of these nutrients.

Additionally, minerals tend to improve water’s taste and palatability. Distilled water, for example, tends to have a very flat, unpalatable taste. However, if the mineral content is too high, water can taste rather salty. Overall, while having these minerals in your drinking water can be beneficial, there aren’t specific recommended levels that apply universally. The ideal amount can vary depending on your diet and health needs, as well as personal preference.

Do ZeroWater Filters Remove Fluoride?

While the ZeroWater filtration technology used in the 5-stage filter system should theoretically reduce fluoride levels in drinking water, ZeroWater has not been certified for the reduction of fluoride. More on that below.

What Are ZeroWater Filters NOT Certified to Remove?

ZeroWater filters lack certifications for several contaminants, including many that are common concerns for consumers, particularly private well owners. Contaminants not certified for reduction by ZeroWater filters include:

• Nitrates*↡
• Bacteria, protozoa, viruses, and other waterborne pathogens like cryptosporidium*
• Pharmaceuticals
• Uranium
• Arsenic↡
• Fluoride↡
• Chloramines↡

*Particularly a concern for those with private wells
↡These contaminants were third-party tested, but they have no certifications

What Does It Mean If a Filter Is Not Certified?

Because certifications are voluntary (and can be quite costly), filtration companies can choose to skip the process altogether and still make a product that works just fine. On the other hand, some companies may choose to skip certification because their product doesn’t work as well as they claim. As a result, the effectiveness of uncertified filters may vary widely from product to product.

Without Certifications, What Should be Removed Based on Technology? 

Though ZeroWater filters lack official certifications for many contaminants, the treatment technologies used in the filtration systems have proven effective against a variety of contaminants.

Note: We strongly recommend performance testing a treatment device that isn’t certified. OR, if you tested your water before acquiring a filter, test your water again once you’ve broken in your filter.

• Activated carbon should be effective at reducing:

• Organic contaminants like pesticides, pharmaceuticals, and disinfection byproducts (e.g. HAA5/HAA9)
• PFAS and larger microplastics 
• Certain heavy metals
• Some larger pathogens like Cryptosporidium and Giardia* 

*When certified for cyst removal or when absolute pore size is <1 micron

• Ion exchange should be effective at reducing:

• Hardness minerals (cation exchange)
• Lead, radium, mercury, and strontium (cation exchange)
• Nitrate, arsenic, uranium, fluoride, and certain PFAS compounds (anion exchange)
  
  

How Do I Know If My Filter Is Working?

The best way to determine if your ZeroWater filter is working is by testing your water. You want to test your water before you invest in a ZeroWater filter so that you can get an idea of your tap water concerns. After all, you want to know what you’re trying to filter out, right?

Public Water Systems

If you’re a customer of a municipal or city water supply, you’ll have some slightly different concerns than someone using a private well. Unlike private well water, municipal water is treated and regulated.

We recommend the Advanced City Water test because it offers detailed analysis of common water health concerns plus advanced analysis including frequently detected disinfection byproducts from the addition of chlorine and chloramine in water treatment.

Private Well Owners

For someone on a private well supply, water quality is totally your responsibility. That includes exposure to bacteria and other common groundwater contaminants like nitrates, pesticides, and heavy metals.

The Essential Well Water test is the recommended way to get a baseline picture of any property served by a private well. It provides analysis of heavy metals, minerals, bacteria, hardness, nitrates, and many other parameters.

Remember: Testing your water through a certified laboratory is the best and easiest way to know whether or not a ZeroWater—or Brita, or PUR, etc.—filter is right for you. You might learn your tap water doesn’t need much treatment at all!

Tap Score’s customer service team of water quality experts are always on call to help you every step of the way.

Enjoyed our overview of ZeroWater filters? Check out our other unbiased filter reviews:

What Do Brita Pitchers Filter Out?
What Do PUR Pitchers Filter Out?
What Do Berkeys Filter Out?