Kirkland Signature Pitcher Review: Lab & Hands-On Testing

Full Analysis of the Kirkland Signature

Filtration: 3.72/5.00

The Kirkland Signature Filtered Water Pitcher by Costco achieved 3.72/5.00 for filtration. How? It did great in our lab testing, and it has a higher count of NSF/ANSI certifications for contaminant reduction (though these are mostly limited to “easier-to-remove” organics). The filtered water was odorless but had some remaining taste.

1. Lab Results: 4.55/5.00

In our lab test comparing an unfiltered and a filtered tap water sample, the Kirkland Signature could remove 8 undesirable impurities and contaminants to below the minimum detection level (so essentially to 100%): chlorine, bromodichloromethane, bromoform, dibromochloromethane, copper, barium, nitrate, and uranium.

Exceptions were:

• Boron – reduced by a moderate 50%.
• Strontium was reduced by 89%, which is high.
• Lithium was reduced by 0%. Although this seems like a particularly bad result at first glance, lithium was already at the lowest detectable level (0.01 ppm) in the unfiltered sample. Due to a limitation of the 2024 analytical method (the lab reported lithium only in 0.01 ppm increments), reduction could only be calculated as either 0% or 100%.
• Fluoride increased by 4%, which most likely represents natural fluctuations. The Kirkland pitcher certainly doesn’t add fluoride to the water, but this data suggests it most likely doesn’t reduce it, either.

Additionally, limescale was reduced by 87%, which should help protect your kettle and/or coffee maker from buildup.

Aside from contaminant reduction, we found silver in our filtered water suggesting potential leaching, but at the lowest level detectable (0.01 ppm) and 10 times lower than the strictest silver heath guideline at 0.1 ppm.

Lab Results Charts

2. NSF/ANSI Certifications and Other Test Data

The Kirkland pitcher is certified for the reduction of 16 contaminants by the WQA against NSF/ANSI standards 42, 53, and 401. However, these certifications are mostly for emerging compounds and other organics like benzene. Chlorine, chloramine, and a few metals (specifically, cadmium, copper, mercury, and zinc, which we also consider “easier to remove” as compared to other metals such as chromium 6) are covered as well.

3. Filtration Process

We assume the Kirkland pitcher uses activated carbon as its primary filter media. Activated carbon removes things like bad tastes and odors, chlorine/chloramine, disinfection byproducts and other organics, as well as certain metals like mercury and lead. Why do we “assume” activated carbon is used? Because we couldn’t really find much information on the process.

4. Taste and Odor Tests

In our test, the freshly filtered water was odorless but had some remaining taste.

Usability: 4.10/5.00

The Kirkland pitcher achieved a usability score of 4.10/5.00, based on its performance in the following categories:

1. Initial system assembly including filter priming (1.00/1.00)
2. Day-to-day use (2.40/3.10)
3. Filter replacements (0.70/0.90)

1. Initial Setup: 1.00/1.00

Assembling the Kirkland pitcher is easy and straightforward. Here’s a quick breakdown of the process:

1. Wash the different components.
2. Immerse your water filter cartridge in cold water for a few seconds. Shake gently while submerged to remove any air bubbles. Discard the water.
3. Place water filter cartridge in the reservoir opening of the pitcher. Press down firmly to make sure the cartridge is seated properly. Rotate if needed.
4. Fill the reservoir with cold tap water and allow it to filter through. The first two fillings will contain filter media sediment and should be discarded.
5. Refill the reservoir – the system is now ready for use.

2. Day-to-Day Use: 2.40/3.10

2.1 Speed & Water Capacity: 0.80/1.20

The Kirkland pitcher is a practical choice for daily use. While some technical specifications are unavailable — since we no longer have access to the unit tested in 2024 and the pitcher may no longer be sold in the U.S. — we do know that the filtered reservoir is ample (~10-cup capacity).

Additionally, this pitcher filters fast enough to meet the daily water needs of the average-sized US and US family households, and it can handle thirst bursts. It even filters on-demand, providing 1 cup in under 60 seconds. In our 2024 filtration speed test, the pitcher could filter 4 cups in a quick 3:30 min.

Finally, the pitcher fits both on the shelves and in the door of a standard fridge (dimensions: 6″x9.75″x10″). Unfortunately, as we lack information on the feed capacity, we don’t know if you’ll be able to fill a large 40-oz bottle with a single refill.

2.2 Handling & Pouring: 1.15/1.15

The Kirkland pitcher is lightweight and pours smoothly even when pouring fast. While handling is made easier with a lighter pitcher, less weight may indicate flimsier construction (e.g., thinner plastic) and/or less filter media (not ideal for optimal filtration performance).

2.3 Refilling: 0.65/0.75

This pitcher has a flip-top lid for easy refilling, though it doesn’t close all the way.

3. Filter Replacements: 0.70/0.90

Filter replacements are very easy, and there is a filter change indicator to remind you when it is time to do so. Rated filter life is 40 gallons. Assuming 300 gallons of yearly water consumption for the average household, we estimate that you will have to change the filter 7.5x annually.

Costs: 5.00/5.00

Based on value for money, the Kirkland pitcher achieved a cost score of 5.00 out of 5.00, indicating it is relatively inexpensive for what it offers compared to competing pitchers (a score of 4.00 represents average value). Notably, its upfront price is well below average compared to the other water filter pitchers we tested, and its annual filter replacement cost is substantially below average.

1. Upfront Price

While it was still in stock on costco.com, the Kirkland pitcher was priced at $29.99, which is well below the $58.53 average across all the water filter pitchers we tested.

2. Long-Term Expenses for Filter Replacements

Based on 300 gallons consumption and a 40-gallon filter life, we estimate $30 in annual filter replacement costs, which is substantially below the $120.13 average across all the water filter pitchers we tested.

3. Product Warranty

The warranty terms for the Kirkland pitcher are unclear.

4. Other Cost Factors

• Filters are claimed to be made in the UK.
• Comes with 1 extra filter cartridge.

Additional

1. BPA-Free Construction

The pitcher is made of BPA-free materials.

2. Frequent Customer Complaints

We read about issues with taste, the lid not closing properly, messy pouring, and plastic cracking.

We also experienced issues with the lid not closing properly. Additionally, the Kirkland pitcher improved the flavor of our tap water but there was still some taste remaining.

While we noted the lightweight construction of the pitcher, which may make it less sturdy, we did not have any issues with it cracking. Finally, we found the pitcher to pour smoothly, even when pouring quickly – no messy spills here.

Bottom Line: Solid, Budget-Friendly Filtration (4.05/5.00)

Filtration weighted at 60%, and usability and cost at 20% each, the Kirkland pitcher scored a final rating of 4.05 out of 5.00.

The Kirkland Signature pitcher by Costco performed great in our lab testing, fully removing 8 contaminants from our water and improving its taste. It also comes with a higher count of NSF/ANSI certifications for contaminant reduction, though they mostly cover the “easier-to-remove” organics.

It is easy to setup, use, refill, and maintain, with minor grievances (i.e. the flip-top lid doesn’t close all the way); it stores plenty of water and filters fast enough to keep up with your daily needs. Plus, it is competitively priced, with low upfront and annual filter replacement costs.

A few more downsides: We don’t have information on the filtration process or warranty. Plus, Costco no longer seems to be selling this pitcher in the US.