Is Kirkland Signature Bottled Water Safe? PFAS + Contaminant Testing Results (2026)
Costco (bottled by Niagara Bottling) brand. No PFAS detected in Consumer Reports testing; low arsenic.
Quick answer
Kirkland Signature is purified water from Costco (bottled by Niagara Bottling), bottled at Multiple US sources, purified by Niagara Bottling. PFAS testing status: PFAS not detected (Consumer Reports). KnowYourExposure rates it B - No PFAS detected in Consumer Reports testing; low arsenic. No bottled water is a reliable long-term PFAS fix: a certified reverse-osmosis or NSF 53 filter removes PFAS from any tap or bottled source for a fraction of the cost.
How we rate: we report published third-party testing, primarily Consumer Reports' 2020 bottled water PFAS investigation, plus brand-published water quality reports. We do not test products ourselves, and where no independent PFAS testing exists we say so rather than estimate.
Quick facts
- Trust rating
- B (No PFAS detected in Consumer Reports testing; low arsenic)
- PFAS testing
- PFAS not detected (Consumer Reports)
- Water type
- purified
- Bottled at
- Multiple US sources, purified by Niagara Bottling
- Parent company
- Costco (bottled by Niagara Bottling)
What we know about PFAS in Kirkland Signature
Kirkland Signature purified water is bottled for Costco by Niagara Bottling from vetted wells, springs, or municipal sources, then treated with micron filtration, reverse osmosis, and ozone disinfection. Consumer Reports testing did not detect PFAS in Kirkland, and available testing put arsenic at about 0.65 ppb, well under the FDA's 10 ppb limit. Reverse osmosis is effective at removing PFAS, which is consistent with the clean result. The FDA's April 2025 testing of 197 bottled waters found none exceeded the EPA's 4 ppt PFAS limit.
Packaging and microplastics
PET plastic. Standard single-use microplastic considerations apply; the water itself tested clean.
Known issues, recalls & lawsuits
- Purified municipal or well water, not a natural spring, despite premium-store positioning
- Bottled by Niagara, whose private-label lines were part of a 2015 E. coli recall (a separate source and issue, not PFAS)
- Source water varies by bottling plant
Safer alternatives to Kirkland Signature
- A home reverse-osmosis system does what Kirkland does for pennies per gallon
- Refill a glass or steel bottle from filtered tap to skip the PET entirely
- For minerals, San Pellegrino publishes its analysis
- Mountain Valley is a glass-bottled option with clean testing
Brands to compare: Aquafina (rated C), Mountain Valley Spring Water (rated A).
Frequently asked questions
- Does Kirkland Signature contain PFAS?
- Kirkland Signature purified water is bottled for Costco by Niagara Bottling from vetted wells, springs, or municipal sources, then treated with micron filtration, reverse osmosis, and ozone disinfection. Consumer Reports testing did not detect PFAS in Kirkland, and available testing put arsenic at about 0.65 ppb, well under the FDA's 10 ppb limit. Reverse osmosis is effective at removing PFAS, which is consistent with the clean result. The FDA's April 2025 testing of 197 bottled waters found none exceeded the EPA's 4 ppt PFAS limit.
- Where is Kirkland Signature bottled?
- Kirkland Signature is bottled at Multiple US sources, purified by Niagara Bottling. The parent company is Costco (bottled by Niagara Bottling).
- Is Kirkland Signature safer than tap water?
- Not necessarily. Kirkland Signature is purified municipal tap water – the same source as your home tap, just filtered. A home reverse osmosis system produces equivalent water for $0.05/gallon.
- What's the safest alternative to Kirkland Signature?
- Mountain Valley Spring Water consistently tests clean for PFAS and is bottled in glass. For everyday use, a Clearly Filtered or AquaTru reverse osmosis system removes 99% of PFAS from any tap source for a fraction of the cost.
- Has Kirkland Signature been recalled?
- Yes – known issues include: Purified municipal or well water, not a natural spring, despite premium-store positioning; Bottled by Niagara, whose private-label lines were part of a 2015 E. coli recall (a separate source and issue, not PFAS).