Phoenix 2.25-gal Gravity Water Filter Review: Lab & Hands-On Test

Full Analysis of the Phoenix 2.25-Gallon Gravity Water System with Carbon + Optional POSTreat Steel Fluoride Reduction Filters

Filtration: 3.80/5.00 (Carbon Filters) & 3.30/5.00 (Carbon + Fluoride Filters)

The Phoenix 2.25-gallon system + carbon filters scored 3.80/5.00 for filtration. How? Most importantly, it achieved solid results in our 2026 lab testing and the filtered water tasted perfectly clean with no odor. However, while this system has extensive third-party testing for contaminant reduction, at least some was not performed over the full filter life. Plus, it only has 2 NSF/ANSI-certified contaminants for chlorine and taste/odor.

The Phoenix 2.25-gallon system + carbon + optional POSTreat fluoride reduction filters scored 3.30/5.00 for filtration. Using this filter combination, it only achieved adequate results in our lab testing, though the filtered water still tasted and smelled perfectly clean. It shares the same 2 NSF/ANSI-certified contaminants and third-party test data with the prior configuration, as they are primarily based on the contaminant reduction performance of the system with the carbon filters installed. The only exception is different test data for fluoride, with the added POSTreat filters increasing the system’s fluoride removal capacity.

1. Lab Results: 4.38/5.00 (Carbon Filters) & 3.75/5.00 (Carbon + Fluoride Filters)

In our lab tests comparing an unfiltered and a filtered tap water sample, the Phoenix’s carbon filters could remove 7 undesirable impurities and contaminants to below the minimum detection level (so essentially to 100%): chlorine, bromodichloromethane, dibromochloromethane, chloroform, copper, iron, and boron.

The following substances remained in our water:

• Manganese was reduced by a solid 78%, which seems to contradict the Phoenix’s third-party test data claiming the reduction of this contaminant by 99.90%. This apparent discrepancy may be explained by differing test conditions: Phoenix evaluated manganese removal from feed water spiked to ~0.50 ppm, whereas our feed water contained a ~52x lower concentration (0.00965 ppm). (The same rationale may also apply to other contaminants for which our observed reduction rates differ materially from those reported by the manufacturer, including cases of potential leaching).
• Barium was also reduced by a solid 69%. As with manganese, this contradicts the Phoenix’s test data which reports 99.90% reduction.
• Strontium was reduced by a very poor 2%.
• Nitrate was reduced by 90%, which is high.
• Fluoride was reduced by a moderate 56%. As with barium and manganese, this contradicts the Phoenix’s test data which reports 75.50% fluoride reduction when using the carbon filters alone.

Aside from contaminant reduction, we found silver (0.00275 ppm) in our filtered water that was not present in the unfiltered water, suggesting potential leaching. However, silver was measured at a ~36x lower level than the strictest silver health guideline at 0.1 ppm. While excess silver does not pose any health risk, at 0.1 ppm it can still cause undesirable cosmetic effects (skin discoloration and graying of the whites of the eyes).

Lab Results Chart: Carbon Filters

In a separate lab test, the Phoenix system with both carbon and fluoride filters installed could remove 9 undesirable impurities and contaminants to below the minimum detection level (so essentially to 100%): chlorine, bromodichloromethane, dibromochloromethane, chloroform, iron, manganese, barium, boron, and strontium.

The following substances remained in our water:

• Copper was reduced by a high 89%.
• Nitrate was reduced by 93%, which is very high.
• Fluoride was also reduced by a high 88%, showing the effectiveness of the optional fluoride filters.

Side note: We assume the slightly improved overall contaminant reduction is due to the fluoride filters slowing down the filtration rate (see below), thereby increasing contact time between the water and the filter media, which in turn likely enhanced the performance of the carbon filters.

Aside from contaminant reduction, we found some form of aluminum (0.944 ppm) in our filtered water that was not present in the unfiltered water, suggesting potential leaching. Concerningly, aluminum was present above the public health goal of 0.6 ppm per the OEHHA.

We assume the fluoride add-on filters are the most likely source of the potential leaching, as we did not detect any aluminum in our lab tests when using the carbon filters alone. These fluoride filters likely contain activated alumina (aluminum oxide, AA), a commonly used media for fluoride removal. That said, we cannot confirm this with certainty based on our lab testing method, and Phoenix does not explicitly state the composition of their FluoRid media.

While it’s generally accepted that AA is a relatively safe, non-toxic form of aluminum when ingested in small quantities due to its low bioavailability – meaning, it doesn’t readily enter your bloodstream after you eat or drink it – adding contaminants to our water runs counter to the whole purpose of water filtration. And even though studies in healthy human volunteers suggest aluminum uptake from the gut is 0.1% or less, the German Federal Ministry of Education and Research states, “the oral intake of aluminum oxide over a long time period should be avoided as elevated aluminum levels in the blood could cause side effects on human health.”

Furthermore, an opinion published by the European Food Safety Authority states that the use of AA in filtration media is safe, as long as aluminum does not leach out of the AA. While rare, the pH and composition of the treated water and even the alumina manufacturing process itself can facilitate this process. Their recommendation is to ensure that aluminum doesn’t leach into the water at a higher level than deemed safe in drinking water. For the EFSA that is .2 mg/L – even stricter than the OEHHA guideline of 0.6 mg/L.

Finally, the detection of aluminum in the filtered water again contradicts the Phoenix’s third-party data which reports 99.90% reduction of this contaminant, and may be subject to the same test-condition considerations discussed above.

Lab Results Chart: Carbon + Fluoride Filters

Non-Potable Water

We have not yet tested the Phoenix system with a non-potable water source. This evaluation is planned, and the page will be updated as soon as testing is completed and results are available.

2. NSF/ANSI Certifications and Other Test Data

The Phoenix has only 2 NSF certifications for contaminant reduction against NSF/ANSI standard 42 for chlorine (99.90%) and taste/odor. Reduction rates are per the official performance data sheet.

However, it has extensive third-party testing against NSF/ANSI standards 42, 53 and other non-NSF/ANSI standards for more than 80 contaminants, but at least some was not performed over the full filter life.

Listed reduction rates include:

• Chlorine (99.90%)
• Chloramines (99.90%)
• Lead (94.00-99.90%)
• PFOA (>99.00%)
• PFOS (>99.50%)
• PFOA + PFOS (>99.66%)
• Aluminum (99.90%)
• Antimony (99.90%)
• Arsenic (99.90%)
• Beryllium (99.90%)
• Boron (99.90%)
• Barium (99.90%)
• Chromium (97.20%)
• Manganese (99.90%)
• Mercury (99.90%)
• Nickel (99.90%)
• Selenium (99.90%)
• Nitrates (99.00%)
• Nitrites (99.90%)
• Fluoride (75.50%; carbon filters only)
• Fluoride (>95.00%; with optional fluoride filters)
• Dozens of VOCs (99.90%)

Non-Potable Water

The Phoenix does not carry NSF/ANSI certifications or verified third-party testing for microbiological reduction (e.g., bacteria, cysts, or viruses).

3. Filtration Process

According to the official Phoenix website, their carbon filters are made from coconut shell granular activated carbon impregnated with “carbon adsorbents.” It’s unclear what those are meant to be, as activated carbon itself already functions as an adsorbent, removing things like bad tastes and odors, chlorine/chloramine, disinfection byproducts and other organics, as well as certain metals.

The Phoenix POSTreat fluoride filters contain FluoRid media, which we assume to contain activated alumina (aluminum oxide). Activated alumina primarily adsorbs fluoride and arsenic.

4. Taste and Odor Test

For both configurations, in our testing the filtered water was odorless and had a perfectly clean taste.

Usability: 4.50/5.00 (Carbon Filters) & 4.46/5.00 (Carbon + Fluoride Filters)

The Phoenix system without the fluoride filters installed achieved a usability score of 4.50/5.00, based on its performance in the following categories:

1. Initial system assembly including filter priming (1.00/1.00)
2. Everyday use (3.30/3.50)
3. Filter replacements (0.20/0.50)

The Phoenix system with the fluoride filters installed achieved a usability score of 4.46/5.00, based on its performance in the following categories:

1. Initial system assembly including filter priming (1.00/1.00)
2. Everyday use (3.26/3.50)
3. Filter replacements (0.20/0.50)

1. Initial Setup & Filter Priming: 1.00/1.00

Assembling the Phoenix system is easy, even with the addition of the optional fluoride filters. The two fold-out instruction sheets provide clear directions as well as a few illustrations. An additional instruction sheet is provided with the POSTreat fluoride filters. Plus, there is a helpful tutorial video on YouTube.

Here’s a quick breakdown of the setup procedure:

1. Wash your hands. Wash the lid, upper chamber, and lower chamber with warm soapy water. Rinse and let dry.
2. Attach the knob to the lid by inserting the screw and washer through the hole in the lid and screwing on the knob (hand tighten only).
3. Place the stainless steel tap washer with domed side facing the spigot onto the threaded part of the spigot, followed by one spigot washer. Insert the thread into the lower chamber hole.
4. Attach the remaining spigot washer over the exposed thread within the lower chamber and secure with the nut, hand tightening only.
5. Remove the wingnut and both washers from the carbon filter to be primed.
6. Invert the wingnut and screw it onto the filter thread with the flat side facing upwards. Place a washer over it.
7. Holding the washer firmly against the spout, turn on cold water tap to a slow flow.
8. Allow water to flow through the filter; you will see water beading on its surface.
9. Hold the filter in place for 2-3 minutes, allowing the cartridge to become fully saturated and flushed. Remove the washer and wingnut when finished.
10. Repeat the same priming process for each additional carbon filter.
11. Push a washer onto the thread of the primed carbon filter cartridge.
12. Insert the cartridge thread into one of the holes of the upper chamber; the washer should sit flush against the base with the thread exposed through the bottom of the hole.
13. Slide on second washer to the exposed portion of the thread. Securely screw on the wingnut snugly against the washer.
14. Repeat this process for the remaining cartridges. All holes without cartridges must have a silicone hole blocker inserted (two hole blockers come pre-installed and need to be removed if using more than two filters).
15. If using the fluoride reduction filter cartridges, they must also be primed before installation. Hold the filter to your faucet using the provided washer while flushing with cold water for three minutes. Next, attach each POSTreat cartridge to the exposed carbon filter thread on the underside of the upper chamber by screwing clockwise.
16. Place airlock clip(s) on the lower chamber.
17. Place the upper chamber onto the lower chamber. Make sure spigot is in the closed position (pointing right).
18. Fill the upper chamber with water, then cover with the lid.
19. Allow the system to fully process the water in the upper chamber and discard the first two batches of filtered water.
20. Now your system is ready to use.

2. Day-to-Day Use: 3.30/3.50 (Carbon Filters) & 3.26/3.50 (Carbon + Fluoride Filters)

2.1 Speed & Water Capacity: 1.20/1.20 (Carbon Filters) & 1.16/1.20 (Carbon + Fluoride Filters)

The Phoenix 2.25-gal system + two carbon filters is well-suited for daily use. It’s even fast enough for on-demand filtering, which we define as 1 cup in <1 minute. In fact, this setup could filter and dispense 1 cup of water in a speedy ~47 sec and 4 cups of water in ~2:52 min in our filtration speed tests.

However, as the spigot sits above the bottom of the lower chamber, the system must process and collect ~34 oz of water before any can be dispensed, which took ~2:25 min. As a result, starting from an empty system, the total time to filter and dispense 1 cup was ~3:12 min, while dispensing 4 cups took ~5:17 min.

Requiring only ~50:03 min to fully filter and dispense the entire feed tank, the Phoenix system with carbon filters can produce large volumes relatively quickly for a gravity system. It’s definitely fast enough to handle 8-10 cup/hour thirst bursts for average US households, which we assume consist of 2.55-3.15 people.

Predictably, the addition of the fluoride post-filters to the carbon cartridges slows things down a little. This configuration is still suited for daily use but on-demand filtering takes just a little more patience, producing 1 cup of water in ~1:17 min and 4 cups in ~3:39 min in our speed tests. However, it required ~9:30 min to collect the ~34 oz needed to reach dispensing level, so the time to filter and dispense 1 cup is ~10:47 min and 4 cups is ~13:09 min if starting from an empty system.

That said, at ~1:13 hr to fully filter and dispense the entire feed tank, the Phoenix system with carbon + fluoride filters is still plenty fast to handle typical thirst bursts. Plus, while we evaluated both configurations with two parallel flow paths, the Phoenix can accommodate up to four carbon and consequently four fluoride filter elements in parallel, which would roughly double filtration speed relative to our two-filter setup.

Dispensing filtered water from a full lower reservoir is also extremely fast – for both setups, we measured about 2 seconds for 1 cup. This system also includes an airlock vent clip to help maintain full filtration and dispensing speed.

The Phoenix housing has a 1.66-gal (~26.6-cup) feed tank*, when used with two carbon cartridges – fluoride filters don’t make a difference here. However, as these POSTreat filters take up some space in the lower chamber, the clean tank capacity decreases from 2.08-gal (~33.3-cup) to 1.98-gal (~31.7-cup) with two elements present.

Either way, you can easily fill a 40-oz bottle or 2-quart pitcher from a single refill. Assuming 25.5-31.5 cups of daily water consumption for the average US households, we estimate 1-2 daily refills for both configurations when filling the upper chamber all the way to the top* – consistent with the other gravity water filters we tested.

However, actual refilling frequency will likely vary considerably depending on each household’s needs and preferences. Given the relatively slow filtration speed inherent to gravity systems, most users likely would not want to wait until the feed tank is empty and the clean water fully depleted before refilling – even if the Phoenix configurations reviewed here are among the fastest options. Realistically, it is more practical to top off the feed tank at strategic times, such as before heading out to work or before bed, so the longer wait time is less disruptive. However, this requires some ongoing judgment from the user to ensure that the added feed water volume does not cause the clean tank to overflow.

2.2 Dispensing: 1.00/1.00

Using a full clean tank, dispensing water is extremely fast and without splashing, unless the spout is fully opened very quickly. The handle twists smoothly, and there is no dripping after the pour.

Due to the spout height, the system must be placed at the counter edge to dispense, unless you use the optional tank stand sold by Phoenix – this gives you another 6.6″ of clearance to fit a glass underneath. That said, you still won’t be able to fit a standard 40-oz bottle or 2-quart pitcher under the spout, even with the added height from the stand.

One minor grievance: dispensing the last 34 oz of water requires additional steps. The spigot sits slightly above the base of the clean tank, which means the last ~4 cups of water cannot be poured unless you are tilting the tank forward or manually ladle out the remaining water. However, this is a common limitation and applies to almost all gravity filters we tested.

2.3 Refilling & Size: 0.80/1.00

Refilling the Phoenix is straightforward. Simply use a pitcher or other container to fill the upper chamber with water. There are no max fill lines, however, and instructions do not specify a fill amount.

The included lid fits loosely but still keeps your feed water well covered. Plus, an optional water level spigot can be purchased separately from Phoenix for easy monitoring of your clean water level, which we highly recommend. Without it, the only way to accurately gauge the amount of water in the clean tank is to lift the upper chamber – something that can be cumbersome depending on how much water remains inside.

Measuring 8.5″x19.45″x10.3″ (WxHxD) including the lid’s knob and spigot, the Phoenix doesn’t fit under most kitchen cabinets (18″ clearance). Additionally, using the optional tank stand further increases the height.

Excluding the stand, it weighs 6.6 lbs with two wet carbon filters installed – increasing to 9.8 lbs with the addition of two saturated POSTreat filters. In both cases, weight is about average for the gravity systems we tested when compared to analogous configurations. Its footprint is also about average, occupying ~56.75 in² (~0.39 ft²).

2.4 Other: 0.30/0.30

The Phoenix system includes a rubber ring on the bottom tank, preventing scratching or sliding on your counter tops. Alternatively, the optional tank stand comes with rubber-gripped feet which also prevent unwanted movement.

2.5 Outdoor Use

With tanks and a spigot made of 304 stainless steel, the Phoenix is durable enough for outdoor use.

Its stowed size of 8.5″x13.25″x8.5″ (WxHxD; knob and spigot removed) and 6.6-lb or 9.8-lb weight (with two wet carbon filters, +/- two wet fluoride filters, and excluding the stand) are comparable to competing systems, making it a reasonably portable option as well.

3. Filter Replacements: 0.20/0.50

Filter replacements are easy. The carbon cartridges are readily accessible from inside the upper chamber, and the POSTreat filters simply screw onto their exposed threads, which protrude from the bottom exterior surface of the feed tank. However, there is no filter change indicator to alert you when it is time to change them.

Rated filter life is 2,750 gal or 12 months per carbon filter element; 2 cartridges therefore have a combined water filtering capacity of 5,500 gal.

The POSTreat fluoride filters have a rated life of 530 gal per element or 4-6 months, yielding a combined water filtering capacity of 1,060 gal for the pair. The stainless steel housing is reusable, and replacement media is simply poured in after discarding the spent media.

Assuming 500 gallons of yearly water consumption for the average household, we predict the frequency of your filter changes will be dictated by filter age rather than water consumption. Therefore, expect to replace the carbon filters 1x annually and the fluoride media 2-3x annually.

Costs: 5.00/5.00 (Carbon Filters) & 4.27/5.00 (Carbon + Fluoride Filters)

Based on value for money, the Phoenix 2.25-gal system incl. optional tank stand and water level spigot plus two carbon filters achieved a cost score of 5.00 out of 5.00, indicating it is priced below average for what it offers compared to competing systems (a score of 4.00 represents average value). Notably, its upfront price is slightly below average and its annual filter replacement costs are well below average compared to the other gravity filter systems we tested.

Similarly, the Phoenix 2.25-gal system incl. optional tank stand and water level spigot plus two carbon and two fluoride reduction filters achieved a cost score of 4.27 out of 5.00, again denoting it is priced below average for what it offers compared to competing systems. While its upfront price is around average, its ongoing filter replacement costs are slightly above average compared to the other tested gravity filter systems.

1. Upfront Price

As of March 6, 2026, the Phoenix 2.25-gal system including two carbon filters is priced at $189. Adding the optional water level spigot ($74) and tank stand ($52) brings the upfront total to $315, which is slightly below the $384.81 average across all the tested gravity filter systems. You can save an additional $20 with a filter subscription.

The same system with the addition of two POSTreat fluoride filters is priced at $259. Adding the optional water level spigot ($74) and tank stand ($52) brings the upfront total to $385, which is around average for the gravity filter systems we tested. You can again save $20 with a filter subscription.

2. Long-Term Expenses for Filter Replacements

Based on 500 gallons consumption and a 5,500-gal or 12-month filter life for two carbon cartridges, we estimate $129 in annual filter replacement costs, which is well below the $234.50 average across all the tested gravity filter systems. Plus, you can save an additional $10 with a filter subscription.

Adding the two POSTreat fluoride filters, we estimate another $140 in ongoing filter media expenses given its rated life of 1,060 gal or 4-6 months for the pair. In combination with the carbon filters, this brings the total to $269 for annual filter replacement costs, which is slightly above the $234.50 average across all the tested gravity filter systems. However, you can save $10 or $20 with a subscription for the carbon filters or fluoride media refills, respectively – or $30 for both.

3. Product Warranty

The Phoenix system’s warranty covers the stainless steel chambers (10 years), spigot, carbon filters, and fluoride filter housing (1 year), and all other parts (6 months). They also provide a 100-day money-back, satisfaction guarantee.

4. Other Cost Factors

• Airlock vent clip prevents slow filtration/dispensing caused by an air-tight connection between the upper and lower chambers.
• Stainless steel water bottle included with the system.
• The optional water level spigot uses a plastic handle.

Additional

1. Construction

The system feels sturdy and well built, with 304 stainless steel upper + lower chambers and spigot. It has a nice, highly reflective finish – some may find this appealing, but it’s also more likely to show smudges.

2. Size Options

The Phoenix gravity water filter system comes in 4 size options: 0.26, 1.5, 2.25, or 3.25-gal.

3. Cleanable filters

You can remove and clean the carbon filters using a soft brush or scouring pad while running under cold water. This helps to restore the flow rate, which may slow over time due to clogging.

4. Packaging

The Phoenix system is nicely packaged and well protected with extensive bubble wrap. Plus, the tanks are wrapped in a mesh-like cloth instead of standard plastic, protecting your investment while also giving it a more high-end feel.

5. Frequent Customer Complaints

We read about issues with ineffective filtration, water bypassing the filter elements, leaking, and overall quality concerns.

We did not experience these issues firsthand.

Carbon Filters Bottom Line: #1 Budget Pick + #1 for Usability (4.18/5.00)

Filtration weighted at 60%, and usability and cost at 20% each, the Phoenix 2.25-gal system with carbon filters scored a final rating of 4.18 out of 5.00.

The Phoenix 2.25-gal system with carbon but without the optional fluoride filters is our top pick for budget-friendly gravity water filter. It also claims the #1 spot for usability, as it is very easy to set up, use and maintain, and processes water relatively quickly for a gravity filter system. Plus, it completely removed 7 contaminants in our lab tests and produced clean-tasting water with no odor. However, it has only 2 NSF/ANSI-certified contaminants for chlorine and taste/odor; while it has extensive third-party testing for 80+ impurities, at least some was not performed to full filter life – and there’s none for germ reduction.

Sturdy 304 stainless steel construction, a 10-year tank warranty and 100-day satisfaction guarantee add further value. While upfront price is slightly below average, ongoing costs are well below average, making this system a great option for cost-conscious individuals seeking a user-friendly gravity system with solid contaminant removal performance.

Carbon + Fluoride Filters Bottom Line: We’re Worried About Potential Aluminum Leaching (3.73/5.00)

The Phoenix 2.25-gal system with carbon filters + POSTreat fluoride reduction filters scored a final rating of 3.73 out of 5.00. Why the lower score, you ask?

The addition of the POSTreat filters did increase fluoride removal, and in many respects, the usability of the two systems was nearly identical – only the filtration speeds were predictably a bit slower with the added in-line fluoride filter elements. Plus, in lab testing, the fluoride configuration aided with overall contaminant reduction, likely due to increased contact time between the water and the filter media, which appears to have benefited the carbon filters as well.

However, we also observed evidence of potential aluminum leaching above the strictest health guidelines. While it’s likely the less worrisome activated alumina (AA) variant, we don’t know for sure – nor can we readily monitor whether this probable AA leaches the more concerning elemental aluminum, which we’d rather avoid. Frankly, we don’t want to introduce additional contaminants into our water.

Combined with the added upfront and ongoing costs, this makes it difficult for us to recommend the POSTreat filters. In our view, it’s best to skip them altogether.