Kirkland Signature vs Mountain Valley: which water is healthier?

Updated · Scores from third-party lab reports · How we score

Mountain Valley is the healthier choice, scoring 68/100 versus 63/100 for Kirkland Signature. The biggest differences are packaging material and water source.

Kirkland Signature Purified Water Plastic Bottle

Kirkland Signature

Kirkland Signature Purified Water Plastic Bottle

63
Mountain Valley Spring Water Glass Bottle

Mountain Valley

Mountain Valley Spring Water Glass Bottle

68

Side-by-side comparison

Kirkland SignatureMountain Valley
Purity score63/10068/100
Product comparedKirkland Signature Purified Water Plastic BottleMountain Valley Spring Water Glass Bottle
TypeStillStill
Water sourceMunicipal SupplyMountain Spring
PackagingPlasticGlass
Microplastics riskHighLow
Lab testedYesYes
PFAS testedYesYes
Contaminants flagged15
pH5.98.2
TDS (minerals)—202 ppm
Fluoride0 mg/L—

Score breakdown

FactorKirkland SignatureMountain Valley
Lab report indexed45/4545/45
Contaminants17/502/50
Water source15/2525/25
Mineral preservation17/1717/17
Packaging material2/2222/22
Cap material7/70/7
PFAS testing5/55/5

Each brand is represented by its most popular product. See all products from Kirkland Signature and Mountain Valley.

Frequently asked questions

Which is better, Kirkland Signature or Mountain Valley?

Mountain Valley is the healthier choice, scoring 68/100 versus 63/100 for Kirkland Signature. The biggest differences are packaging material and water source.

Is Kirkland Signature or Mountain Valley better for avoiding microplastics?

Kirkland Signature (plastic) has a high microplastics risk and Mountain Valley (glass) has a low risk, based on packaging material.

Which has more minerals, Kirkland Signature or Mountain Valley?

Total dissolved solids (TDS) is not reported for both products, so check each product page for its mineral list.

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