Our recommendations are made independently through Research & Testing. We may receive commissions from purchases made via our links.

Culligan FM-25 Faucet Water Filter In-Depth Review

Matthew Lee
Lap Vo
Test Lead
Nguyen Ntk
Visual Specialist
Tested Using Methodology v1.0
The silvery Culligan FM-25 is attached to a kitchen faucet. Clean water is being deposited into a cup underneath.

Culligan FM-25 Faucet Specifications

Price at publication $40.27
Dimensions L3 x W4.5 x H3.5 inches
Weight 1.1 lbs
Capacity 200 gals
Qualifications NSF/ANSI Standard 42 and 53
Filtering flow rate 0.5 GPM
Warranty 2 years

Overall Verdict

If you're plagued with the harsh aftertaste of chlorine in your tap water, we can verify that the Culligan FM-25 faucet-mount water filter can solve your problem. In our chlorine filtering tests, the FM-25 could eliminate all traces of chlorine in the water.

The filter boasts sturdy construction, ensuring long-lasting use. It also has a very user-friendly design with a push-pull knob that you can use to transition between plain and filtered water. Notably, the knob automatically resets to produce plain water when the tap is shut off, helping you to save water.

The only minor drawback is the reduced flow rate while in filtration mode. This may be a deal-breaker if you're accustomed to high-pressure tap water.

Things We Like

  • Excellent chlorine filtering ability with a near-100% filtration rate.
  • Good build quality, premium materials.
  • The locking collar fixes the filter solidly to the tap, preventing it from wiggling around.
  • The push/pull routing valve is easy to use. Automatically reset after the tap is shut off.
  • Replacement filters are cheap, easy to find.

Things We Don’t Like

  • Very low flow rate in filtration mode (0.5 GPM).
  • The filter of our unit leaked during testing.

The Culligan FM-25 faucet-mount water filter is a mid-range water filter that comes with a capable filter and an attractive, silvery design. The filtering block is rated against chlorine, lead, and bacteria like cryptosporidium and giardia cysts. The bacteria filtration capability makes it an outlier (in a good way!) among the other models in our database.

If a good blend between filtration efficiency and aesthetic is what you’re looking for, this filter can be one of the better fits for you.

  • Updated Feb 8, 2023:

    Review published.

Culligan FM-25 Faucet Mount Filter’s Performance

While the Culligan did excellently in the chlorine test, being able to completely neutralize all traces of free chlorine in the water, the filter didn’t do well in the flow rate test. The Culligan barely passed with a slow filtering flow rate of 0.5 GPM (in contrast to the initial tap flow rate of 2.2 GPM).

10Chlorine Test

Culligan FM-25 Faucet Mount Filter Chlorine Test 3
The Culligan FM-25 filter mounted on a tap. To its left is the testing result pad with two activated test strips.
Two water testing strips are laid on a color chart to show the Culligan FM-25’s filtration performance.
10+ mg/l
~0 mg/l

The Culligan excelled in our chlorine filtration test. The control sample, which was highly chlorinated tap water, was compared to a sample filtered by the Culligan. The results from the testing kit showed that the Culligan was able to filter out nearly all chlorine traces in the water, returning a total chlorine value of approximately 0 mg/l.

The Culligan was awarded a perfect score of 10 for its performance in this test.

5.0Flow Rate Test

20 secs
0.172 gallons
Flow Rate
0.5 GPM

The Culligan FM-25 passed the flow rate test by hair.

The filter's flow rate in filtration mode was found to be 0.5 GPM, compared to the tap's flow rate of 2.2 GPM. A flow rate of 0.5 GPM is considered the minimum threshold for a passing score in our benchmark. The Culligan FM-25's result met this threshold, allowing it to pass the test.

Nonetheless, in real use, we still found the Culligan too slow at filtering, especially compared to other filters in the same price range, such as the Waterdrop WD-FC-06.

Culligan FM-25’s Design

The Culligan faucet-mount water filter boasts a solid design, sporting a stainless steel exterior and a white plastic interior that Culligan has claimed to be antimicrobial. 

While it may not be the best-looking filter on the market, its rugged construction promises longevity. The filter housing should easily last a year or two with regular use on the tap before it becomes worn-out enough to warrant a replacement.

Culligan FM-25 Faucet-Mount Filter: In the Box

The glossy housing of the Culligan FM-25 faucet-mount water filter next to its shipping box, adapters, and paperwork.
The glossy housing of the Culligan FM-25 faucet-mount water filter next to its shipping box, adapters, and paperwork.
Two faucet adapters made from white plastic with black rubber seals at the top

The filter comes as a single piece with the filtering block already locked onto the housing. You can install the filter immediately with no need for assembly.

In total, you get three pieces in the box.

  • The filter (with the filter block already installed within)
  • Paperwork (manual, warranty cards, etc.)
  • Two adapters with rubber seals


Culligan FM-25 Faucet Mount Filter Dimensions
3.0" (7.6 cm)
4.5" (11.4 cm)
3.5" (8.9 cm)
1.1 lbs (0.5 kg)

The Culligan FM-25 faucet-mount water filter is a compact and lightweight filter that can easily be attached to most standard kitchen faucets.

The filter weighs 1.1 pounds, making it easy to handle and install. When mounted on our faucet, the weight of the filter isn’t so heavy that the tap would swing around or droop.

In terms of dimensions, the filter has a length of 4.5 inches, a width of 3 inches, and a height of 3.5 inches. The compact design will ensure the filter won’t get in the way while using the tap for hand or dishwashing.

8.3Build Quality

The Culligan FM-25 filter’s side profile, showing its large filter compartment, slip-on collar, and routing valve’s knob.
The Culligan FM-25 filter’s side profile, showing its large filter compartment, slip-on collar, and routing valve’s knob.
The main filter nozzle of the Culligan FM-25, with the “Remove Before Installing” sticker removed.

The Culligan FM-25’s overall build quality is excellent. Although the filter isn’t much by way of aesthetic with a blocky, simplistic design, we really like the solid weight of the filter in the hand.

The chrome plating gives a luxurious look but also leads to confusion. Many customers had reviewed that they thought the filter was made from stainless steel when they first bought it. Closer inspection revealed the filter is actually made from chrome-plated plastic. Only some components, such as the rotating collar and push-pull knob of the routing valve are made from metal.

8.0Filter Piece

The filter piece of the Culligan FM-25 faucet-mount water filter, with white plastic casing and chrome-plated end piece.
The filter piece that comes with the Culligan FM-25.
Filtration Process
Activated Carbon and Ionization Filtration
ANSI Standard 42 and 53
Filter Capacity
200 gallons

Culligan doesn’t go into detail about how its filter block is made, such as what kind of filtering materials are used. But one thing we’re sure of is that the filter block includes a layer of activated carbon.

The company advises flushing the filter for 5 minutes when first installed to remove any carbon residue. And indeed, when we flushed the filter, the water coming out of the filter was blackened by charcoal for around a minute.

10Routing Valve

A close-up view of the push-pull routing valve on the side of the Culligan FM-25 faucet-mount water filter.
A close-up view of the push-pull routing valve on the side of the Culligan FM-25 faucet-mount water filter.
A top-down view of the mounting collar of the Culligan FM-25 along with the push-pull routing valve.
Typeof Valve

The routing valve on the Culligan FM-25 is a rod-shaped knob to the side of the filter’s housing. To switch between plain and filtered water, the user can either pull it out (for filtered water) or push it in (for plain water.)

When the tap is turned on, the filter will be configured for plain, unfiltered water. To activate the filter, pull the knob, and filtered water will flow out of the secondary nozzle.

Remarkably, the knob automatically resets to plain water mode when the tap is turned off. It’ll help you prolong the lifespan of your filter.

Culligan FM-25 Review: Usability

The Culligan faucet-mount water filter is easy to use overall.

The installation process is quick and simple. All it takes is slipping on the rotating collar, tightening, and firmly anchoring the filter to the faucet. If your faucet happens to have internal threading, the filter comes with adapters. The filter didn’t leak at any point during our testing.

The only problem we had with the Culligan was the search for replacement filters online. Culligan offers two filter types for the FM-25, both offering comparable performance, and the only distinction between them is appearance. However, one filter model (FM-25RA) is more expensive than the other (FM-25R). Be mindful when you make your purchase.


The Culligan FM-25 faucet-mount water faucet with a faucet adapter attached to the filter’s mounting port.
The filter with a faucet adapter attached to the mounting port.

The test faucet in the lab has an external thread, so installation is simple and doesn’t require adaptors. The filter's swivel collar is placed on the faucet's nozzle and tightened by rotating the collar.

10Ease of Use

Its lightweight, 1.1-pound design is complemented by the tight locking swivel collar, which helps keep the filter securely in place and prevents swaying or wiggling after installation.

The routing valve, located on the side of the filter, is easy to operate. Turn on the tap and pull the knob outward to access filtered water. The valve automatically resets to plain water mode when the tap is shut off, helping to extend the service life of the filter.

Overall, we found the Culligan FM-25 to be very easy to use. The only usability issue we encountered during the test was its low flow rate, which can be annoying if you’re used to having high flow rate water.

If this is a deal-breaker for you, fortunately, there are plenty of models on the market that can offer higher flow rate while maintaining a good filtration performance throughout, such as the Waterdrop WD-FC-01 or the Brita Basic faucet filter.


Even when fully tightened, a leak was still present on the collar and parts of the filter. The leak on the collar can be fixed with plumbing tape, but the leak on the filter proved more difficult to fix. Even after taking out and reinstalling the filter, the leak persisted. We suspect this is a design issue.


The Culligan FM-25 faucet-mount water filter next to the Culligan FM-25R filter piece.
The Culligan FM-25 faucet-mount water filter next to the Culligan FM-25R filter piece.
An upside down FM-25R filter piece, with chrome-plated end piece and housing made from white plastic.
Filter Indicator
2 months

The capacity for the filter in the Culligan FM-25 is 200 gallons.

Since it doesn't come with a filter change indicator, you'll need to keep track of everything on your own to know when to switch out the filter piece. But according to Culligan, the filter should last you around 2 months.

As of January 2023, replacement filters for the FM-25 are readily available online. 

There are two filters compatible with the FM-25: the FM-25R and the FM-25RA.

Both filters have the same filtration efficiency and are compatible with the Culligan FM-25's filter housing. The only difference is the appearance. While the FM-25R has a glossy metallic finish, the FM-25RA is painted plain white.

Although the FM-25R is the filter piece that’s made to fit the FM-25, it's worth noting that this model is slightly more expensive than the FM-25RA. If you're looking to save money, the FM-25RA will be a better choice, even if the plain white color doesn't match the filter's glossy housing.

About your guide

Headshot of Matthew Lee
Matthew LeeReviewer

Matthew is one of the writers at Healthy Kitchen 101. Working as part of the Review Team, he directly contributes to the production of content for the site’s Product Review pages. Much like the other members of staff, he strives to bring you the most authentic and accurate reviews of kitchen appliances as possible.

Headshot of Lap Vo
Lap VoTest Lead

Lap Vo is head of the Research, Testing, and Review Team (the RTR) at Healthy Kitchen 101. He is responsible for designing and overseeing the testing of kitchen tools and appliances.