ZeroWater Review: Objective, Data-Driven Testing & Analysis

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📊 Scoring Data

We’ve combined quantifiable data with our own subjective testing to rank the ZeroWater filter across 6 different performance categories. You’ll find the scores for the filter pitcher in each category in the table below.

CriteriaResults
Overall Score8.62
Health Related Contaminants83
Aesthetic Related Contaminants99
Performance CertificationCertified for 25% of reduction claims
Filtration Rate2.62 GPH
Component QualityFair
Component CertificationCertified
SetupOutstanding
Servicing RequirementsOutstanding
Costs$0.70/ gallon
Warranty LengthVessels 90 days, filters 30 days
ShippingFree shipping on orders above $60 to continental US
ReturnsNo returns

🎬 Video Review

🚰 Contaminant Reduction

Score: 8.34

Reducing contaminants is obviously the most important factor when looking for a water filter pitcher, so our main aim in our testing was to collect data on which contaminants the ZeroWater pitcher could reduce from our drinking water supply. 

We also looked online to see if the pitcher had been certified by the NSF, WQA, or IAMPO, and these findings also contributed to the overall contaminant reduction score. 

Our Performance Testing

Score: 3.82

We’ve used our Zero Water pitcher to filter water in our home in Colorado. We conducted a before-and-after filtration test using Tap Score tests by SimpleLab to see which contaminants the pitcher could remove.

Good to Know: We analyzed our test data using Tap Score’s HGL (Health Guideline Level), which isn’t as lenient as the EPA MCL limits and prioritizes human health.

Health-Related Contaminants

Score: 8.30

First, we focused on the health-related contaminants that had been detected in our water, and how effectively the ZeroWater filter pitcher removed these contaminants. 

Our water supply is treated well water and contains a number of common groundwater contaminants. Of these, 8 contaminants with potential health effects were detected:

ContaminantMeasurementDetectionHGL
UraniumPPM0.0140
ChlorinePPM10.0003
MolybdenumPPM0.00260.03
CopperPPM0.1630.3
FluoridePPM1.10.8
BariumPPM0.01582
StrontiumPPM0.113
Nitrate (as N)PPM3.510
SulfatePPM8.4500
PhosphorusPPM1none
MagnesiumPPM6.32none
pH7.4none
SodiumPPM9.63none
ChloridePPM14.9none
CalciumPPM25.6none
Total Dissolved SolidsPPM137none

There are a few different health effects associated with these contaminants, including developmental, blood, kidney, and gastrointestinal effects. 

We were the most concerned about fluoride and uranium because these were detected in our water above the Tap Score HGL:

  • 1 PPM of fluoride was detected, exceeding the HGL of 0.8 PPM
  • 0.014 PPM of uranium was detected, exceeding the HGL of 0 PPM

Our filtered water test showed us that the ZeroWater filter had done a great job of reducing 100% fluoride, uranium, barium, molybdenum, nitrate, strontium, and sulfate.

It also reduced 97% copper, bringing the concentration down to just 0.0047 PPM. 

These were exactly the results we were hoping for, showing us that we could rely on the ZeroWater pitcher to greatly reduce or remove all the contaminants we were concerned about in our water supply

However, there was one anomaly that we spotted with our results. While disinfection byproducts weren’t present in our unfiltered water, they were present in our filtered water: our test detected 3.4 PPB of chloroform, a common trihalomethane (THM). 

We think that chloroform was in fact present in our unfiltered water, but due to its volatility, it had already dissipated by the time it was tested. Chloroform was still present in the filtered water by the point of testing, which is why it has “appeared” in the post-filtration results. 

However, this does tell us that Zero Water doesn’t reduce disinfection byproducts very well – something that it doesn’t claim to do, but a disappointment all the same. And due to this, the overall contaminant reduction score was greatly lowered.

Here is a table of our complete ZeroWater lab test results:

ContaminantMeasurementUnfilteredZeroWater% Change
BariumPPM0.01580-100.00%
BicarbonatePPM85.148.53-89.98%
CalciumPPM25.60.2-99.22%
CarbonatePPM0.10.004-96.00%
ChloridePPM14.90-100.00%
ChlorinePPM10-100.00%
ChloroformPPBND3.4n/a
CopperPPM0.1630.0047-97.12%
FluoridePPM1.10-100.00%
MagnesiumPPM6.320-100.00%
MolybdenumPPM0.00260-100.00%
Nitrate (as N)PPM3.50-100.00%
PhosphorusPPM10-100.00%
SodiumPPM9.630-100.00%
StrontiumPPM0.110-100.00%
SulfatePPM8.40-100.00%
Total Dissolved SolidsPPM1378-94.16%
Total THMsPPBND3.4n/a
UraniumPPM0.0140-100.00%

Aesthetic Contaminants

Score: 9.90

We used the included chlorine test strip in our Tap Score testing kit to do our own water chlorine test at home. There was no point in getting our water tested for chlorine at the lab as the results wouldn’t have been accurate – chlorine is highly volatile and dissipates from water quickly. 

The test detected around 1 PPM of free chlorine in our unfiltered water, which is pretty normal for treated water supplies – up to 4 PPM of chlorine is considered safe in drinking water.

The post-filtration test showed us that the ZeroWater pitcher had eliminated chlorine to undetectable levels, which was the ideal result for us.

We also noted that the filtered water was free from all associated tastes and odors, and had a cleaner, purer taste. The filter contains activated carbon media, which is widely used in water filters for reducing chlorine, tastes, and odors. 

Important taste information: Towards the end of the filter life, our filtered tap water took on an unpleasant, slightly acidic taste. This is due to the ion exchange resin degrading, which releases an organic compound called trimethylamine, and has been experienced by numerous other customers (some describe the taste as sour, lemony, or fishy). The only way to prevent this smell was to frequently wash out our pitcher/dispenser and replace the filters on time.

Minerals, Hardness, & Other Water Parameters 

The ZeroWater filter pitcher is a bit different from other more “conventional” filter pitchers.

A big part of Zero Water’s marketing is that its 5-stage filter can greatly reduce TDS. We have issues with this since TDS is only an indicator of water quality – we’ve discussed this in more detail later. 

Zerowater tds meter

Most other water filters are designed to reduce the bad stuff (chemicals, heavy metals, and so on), while retaining minerals and healthier or non-harmful impurities. So, we wanted to know how the ZeroWater filter differed in this respect.  

Calcium, magnesium, and sodium were all detected in our unfiltered water, as well as 137 PPM of total dissolved solids (TDS) and 90 PPM of water hardness.

Post-filtration, our water’s calcium concentration had been reduced by 99%, and magnesium and sodium by 100%. We’d prefer to retain these healthy, taste-enhancing ions. Still, our water’s pH only dropped by 0.4, from 7.4 to 7.0, so at least it was still in the neutral range. 

As for our water’s TDS concentration, this was unsurprisingly reduced to 8 PPM – only slightly falling short of ZeroWater’s promises to reduce TDS to 0.

Interestingly, our included TDS meter gave a reading of 0, and continued to give this same reading a few weeks later. This is likely due to the higher precision of the lab’s instruments compared to the handheld meter, but was interesting to us given that ZeroWater actually recommends replacing the filter once the TDS meter reads 006.

The filter also reduced hardness down to 0 PPM, which isn’t a very useful ability of a point-of-use water filter – softening water only really has plumbing/appliance benefits and isn’t safer or healthier to drink. 

Performance Certifications

Score:  8.00

We scored the ZeroWater pitcher in the performance certifications category by comparing how many contaminants the filter has been certified to reduce with how many the manufacturer claims it can reduce. 

The Zero Water 5-stage water filter is NSF certified to Standard 42 and Standard 53 for the reduction of 6 contaminants: chlorine taste and odor, chromium 6, lead, mercury, PFOA, and PFOS.

The manufacturer has obtained independent testing using EPA-approved methods to demonstrate the filter’s ability to remove 24 different contaminants from tap water (view the independent lab testing data here).

We appreciate ZeroWater’s transparency, but we think the manufacturer could have obtained certifications for reducing a broader range of contaminants. As it stands, the filter is only certified to reduce 6 out of the 24 contaminants ZeroWater claims it can reduce.

We also wish the filter could be tested to reduce additional contaminants of concern, including pesticides, chloramine, pharmaceuticals, radionuclides, microplastics, and VOCs – especially given that some of its closest competitors have been tested to remove 200+ or even 300+ contaminants.

Compare ZeroWater’s contaminant removal claims with its performance certifications in this table.

Contaminant15 Gallons Filtered130 Gallons Filtered20 Gallons FilteredCertification
Antimony99%96%99%
Arsenic III98%85%63%
Arsenic V98%93%94%
Barium99.9%99.9%96%
Beryllium97%97%94%
Cadmium97%97%97%
Chromium 398%94%93%
Chromium 699%99%93%NSF 53
Copper99.9%99.9%93%
Iron99.9%99.9%99%
Lead99%99%85%NSF 53
Manganese99%99%49%
Mercury92%91%92%NSF 53
Selenium99%98%79%
Silver99.9%96.0%37%
Thallium99%98%91%
Zinc99.9%99.9%95%
Asbestos99%98%89%
Chlorine99%99%95%NSF 42
Cyanide99.9%99.0%85%
Fluoride99%91%3%
PFOA95.1%94.9%NSF 53
PFOS95.1%94.9%NSF 53
Nitrate98%78%48%
Nitrite99%88%93%

Our Problem With ZeroWater’s TDS Removal Marketing

We mentioned earlier that ZeroWater puts a big emphasis on the fact that its filters can reduce TDS, or total dissolved solids, down to 0 in tap water.

We understand that many folks like knowing that they’re removing virtually all their water’s dissolved solids, and using the TDS meter for proof.

The problem we have with this is that it has misled a lot of customers into believing that reducing TDS down to zero is absolutely essential, and that all dissolved solids are bad.

Some customers are also led to believe that if another water filter isn’t capable of doing this, then it is inferior.

This isn’t true: Some dissolved solids, like healthy minerals, for instance, are good for us. But these minerals get reduced by the ZeroWater 5-stage filter.

Do we need healthy minerals? According to this 2017 review of 67 studies, various minerals in water have positive effects on digestion and skeletal health, and may even reduce the risk of coronary heart disease. However, folks who follow a healthy diet don’t need to obtain minerals from their drinking water because they’ll get plenty from their foods.

Plus, some contaminants don’t affect TDS, including non-ionic compounds (disinfection chemicals, byproducts, and pesticides), dissolved gasses like nitrogen, and suspended solids like silt, clay, and microorganisms. None of these can be measured by a TDS meter. Even if your water’s TDS is low, it might still contain certain harmful impurities.

That said, in ZeroWater’s case, there is an activated carbon component that should adsorb many of these other organic contaminants that aren’t detected by the TDS meter. This Drinking Water And Health evaluation found that disinfectant chemicals like chlorine, chlorine dioxide, and ozone “react readily with carbon” and are effectively adsorbed by an activated carbon filter (something we confirmed in our own testing).

We personally prefer to retain certain healthy dissolved solids in our water. We would much rather see more certification evidence that ZeroWater filters can remove specific contaminants that we’re concerned about, instead of knowing that they can remove TDS as a whole.

🚦Filtration Rate

Score: 10.00

To award the ZeroWater pitcher a score in this category, we timed the filtration process to see how long it took to filter our water. 

We expect gravity filters like the ZeroWater pitcher to filter water more slowly because they don’t have the benefit of water pressure from a plumbing system.

This is one of their setbacks compared to other types of filters, like faucet filters and under-sink filters, which are connected to a water line and deliver filtered tap water on demand.

But the Zero Water filter system had a pretty quick filtration rate of 2.62 GPH (gallons per hour) in our testing, based on its ability to filter 0.391 gallons in 08:56 minutes. 

We tested a new filter, so we expect that filtration rate will slow as the filter media becomes saturated with contaminants. 

📐 Design

Score: 8.80

We awarded the ZeroWater pitcher’s design score once we’d had a chance to have hands-on experience with the pitcher and get a feel of its component quality. We also looked for any materials safety certifications that the pitcher might have obtained. 

The ZeroWater products we have personal experience with are:

zerowater pitcher and dispensers on countertop table

For this review, we tested the 12-Cup Ready-Pour Pitcher, but all ZeroWater pitchers and dispensers use the same 5-stage filter. 

The concept of water filtration is simple: you fill the top compartment of the pitcher or dispenser, then wait for the water to filter through into the bottom compartment. Then, depending on whether you’re using a pitcher or a dispenser, you can pour water from the spout or open the spigot.

The package we received contained the following items:

  • The pitcher body
  • The upper reservoir
  • The first filter
  • The lid
  • A TDS meter
Brian holding the ZeroWater 12 cup filter cartridge

We found that the 12-Cup Ready-Pour Pitcher was lightweight and easy to carry – we could carry it with one hand even when it was full.

Models & Sizes

The 5-stage ZeroWater filter can be used in a number of pitcher and dispenser models and sizes/water-holding capacities. These are:

Most pitcher/dispenser models come in ZeroWater’s blue and white brand coloring and aren’t available in other colors. They’re all made from plastic apart from the Glass Ready Pour Dispenser, which (in our opinion) has a more modern, attractive-looking design.

Component Quality

Score: 8.00

The majority of the Zero Water filter pitchers and dispensers are made of BPA-free polypropylene and ABS (a terpolymer).

Polypropylene is a super popular material used for water filter pitchers because it’s durable, flexible, and highly resistant to moisture absorption, as well as being free from BPA and BPS. ABS is a food-grade plastic, which is non-leaching and mold-resistant. We did find that the plastic feels a bit thinner and flimsier than pitcher/dispenser units made of Tritan plastic.

Brian assembling the ZeroWater 12 cup

We know many folks want to avoid using plastic as much as possible, and in that case, ZeroWater’s Glass Ready Pour Dispenser might be the best option. But it’s not the most practical or portable due to its extra weight – it comes in at 12.5 pounds (in comparison, the 32-cup Ready-Read dispenser weighs just 5.5 pounds), and there’s still plastic in some of its components, like the spigot and the filter cartridge. 

Certification

Score: 10.00

The ZeroWater pitcher has a materials safety certification as a component of its performance certifications. 

That’s exactly what we were looking for – it tells us that the pitcher meets the standards of the official testing organization (the NSF) for the quality and safety of its materials. 

Filter Materials

The Zero Water filter cartridge that’s used across all dispensers and pitchers combines five filtration stages, including 3 layers of physical filtration, ion exchange resin, and activated carbon media.

There are no surprises here – all these materials are widely used by water filter manufacturers and are considered safe and effective for their purpose. 

This filter media sits inside a BPA-free polypropylene casing.

⚙️ Setup

Score: 9.50

We set up our ZeroWater pitcher ourselves, so we could evaluate how easy the process was, and how long it took. 

We found that the pitcher, and the other ZeroWater pitchers and dispensers we’ve used, were easier to assemble and set up than many similar systems.

The big advantage for us was that we didn’t have to prime or soak the filter, so we could just attach it to the unit and start filtering straight away.

Most similar pitcher filters at least need to be flushed under running water, but ZeroWater filters don’t. 

ZeroWater’s 7-step assembly instructions in the user manual are really simple to follow, and the process took us less than 5 minutes in total. We just cleaned the pitcher in warm water and mild soap, twisted the filter into the bottom of the reservoir, and filled the reservoir with cold water to be filtered.

🔧 Maintenance

Score: 8.25

The data we used for this category combined our own subjective analysis of the ZeroWater filter’s servicing requirements and an objective calculation of the filter’s cost per gallon based on information provided by the manufacturer. 

Servicing Requirements

9.50

Replacing the filter in our pitcher was the main servicing requirement, and it was easy – like the new filters, the replacement filters didn’t need to be primed, soaked, or flushed before they could be used.

As we mentioned, our ZeroWater pitcher came with a TDS meter. This can be a handy tool for checking whether the filter needs to be replaced – ZeroWater recommends changing the filter when the TDS reading is 006. 

You can also go off taste, since we and many other customers noticed a distinct taste to their water when a filter change was needed. But the TDS water tester is a more accurate way to determine the filter performance.

The only other servicing requirement was to wash the pitcher and reservoir in warm, soapy water every few days. ZeroWater pitchers and dispensers must be hand-washed and aren’t dishwasher-safe. 

Costs

Score: 7.00

The ZeroWater pitcher has a higher projected ongoing cost than many of its competitors, at $0.70/ gallon. ZeroWater gives different filter lifespan estimates for different use situations. We calculated the filter’s ongoing cost using 25 gallons based on the “typical” information on this chart:

Tap Water TDSContaminant LevelDescriptionExpected Capacity
000-001Meets FDA
Standards
No known municipalities.N/A
002-050ModerateNaturally occurring in only a few cities.
Can still contain dangerous impurities such as lead.
≥ 40 gallons
051-200Typical RangeMost water in the USA falls into this group.25-40 gallons
201-300HighExpect slightly lower capacity.15-25 gallons
301-400Exceptionally HighMost users will notice shorter filter life.8-15 gallons
401+ExtremeThe highest TDS water. Expect lower
capacity when reducing your water to 00.
≤ 8 gallons

This is a pretty high cost per gallon compared to similar pitcher filters. For instance, we calculated the Brita Elite’s cost per gallon as just $0.17, and the PUR Plus’ ongoing cost as $0.27 per gallon.

There are a couple of factors at play here. The first is that the lifespan of the 5-stage ZeroWater filter is one of the worst we’ve seen for a gravity filtration system. Then there’s the fact that ZeroWater filter replacements are expensive given their short lifespan. 

The ZeroWater 5-Stage Filter can filter just 40-50 gallons of water before it needs to be replaced.

Our tip: To extend the lifespan of your ZeroWater filter, pre-filter your water through a cheaper system first to reduce some contaminants.

Experts recommend that we aim to drink around half a gallon of water per day. Let’s say you have two people in your household, so you filter a gallon of tap water a day in the ZeroWater pitcher.

That means it’ll last you around 40-50 days, or 5-7 weeks on average. We found that our filters lasted around 1-2 months, but some customers said their filters only lasted 2-3 weeks – it depends on your water quality and daily water usage.

🏢 Company

Score: 7.50

We assessed ZeroWater in this category by examining its warranty, shipping, and returns policies. 

Warranty 

Score: 7.50

ZeroWater offers a 90-day warranty for all vessels (pitchers, dispensers, reservoirs, etc.) and TDS meters, and a 30-day warranty for its filters, against manufacturing defects from the date of purchase. 

The warranty doesn’t guarantee a specific filter life, so you can’t make a warranty claim if your filter doesn’t last 30 days – it only applies to manufacturing defects.

Find ZeroWater’s warranty information here. 

Shipping 

Score: 9.00

ZeroWater currently offers free shipping on all orders above $60 to customers in continental US. That means you’ll probably have to pay a shipping fee if you go for one of ZeroWater’s pitcher filter systems. The fee depends on your location. 

Returns

Score: 6.00

We were disappointed to see that ZeroWater doesn’t have a specific returns policy. The company’s returns and refund policy page lists the same information that appears on the warranty page. 

According to this information, ZeroWater will replace defective parts free of charge, but there’s nothing to suggest that customers can obtain refunds in any situation. 

❔ FAQ

Does Zero Water Filter Remove PFAS?

Yes, the Zero Water filter can reduce PFAS in drinking water. In fact, ZeroWater filters are NSF certified to reduce PFAS – the best industry-backed assurance that the filters can effectively reduce PFAS chemicals.

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  • Brian Campbell
    President & CEO, CWS, CWR

    Brian Campbell, a WQA Certified Water Specialist (CWS) and Certified Water Treatment Representative (CWR) with 5+ years of experience, helps homeowners navigate the world of water treatment. After honing his skills at Hach Company, he founded his business to empower homeowners with the knowledge and tools to achieve safe, healthy water. Brian's tested countless devices, from simple pitchers to complex systems, helping his readers find the perfect fit for their unique needs.

8 thoughts on “ZeroWater Review: Objective, Data-Driven Testing & Analysis”

  1. Avatar for Brian Campbell

    Great article, thank you so much for the analysis. I just bought my mother a ZeroWater pitcher around Christmas, I’m glad to know I made a good choice! I chose a Clearly Filtered one for me, do you have any testing on that brand?

  2. Avatar for Brian Campbell

    What are your thoughts on Ion-Exchange / Alkaline filtration? I started with Brita, then Zero Water, RainSoft (waste softener & reverse osmosis) the best by far in my opinion. And due to divorce my ex has the…so in my rental I am trying the ion / alkaline filtration. I am happy but also have many questions. Care to comment?

    1. Avatar for Brian Campbell

      Hey Jay, thanks for your comment. There are two types of ion exchange: cation and anion. Each process removes different substances, depending on ion charge. Learn more here https://waterfilterguru.com/what-is-ion-exchange/

      A water softener uses anion exchange to remove hard water minerals, protecting your home’s plumbing and water based appliances.

      A reverse osmosis system on the other hand pushes water through a semipermeable membrane, greatly reducing or removing essentially everything. It’s a good idea to pre-treat the water with a water softener before the RO if the water is really hard. This serves to protect the RO membrane and internal system components. Because reverse osmosis demineralizes water, you might want to consider remineralization to add healthy minerals back to the treated water which will increase pH and palatability.

      Let me know if you have any more questions!

  3. Avatar for Brian Campbell
    brianna catapano

    Would you prefer clearly filtered water pitcher over the zero water ? Also we just bought a house that has a Rain Soft reverse osmosis system installed under the kitchen sink. Do you know if this is a good water filtration system.

    1. Avatar for Brian Campbell

      It depends on what contaminants are present, and your own preferences. Depending on the contaminants, I would personally go for Clearly Filtered, but ZeroWater is a solid choice too. That said, if you already have a reverse osmosis system then an additional water filter pitcher would not be necessary (assuming the RO is working as intended)

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