We bought seven brands at a grocery store in Los Angeles and screened every one. All seven tested positive for particles consistent with microplastics. The aluminum cans scored the same as the plastic bottles. So did the glass.
Round 1 of 12, tested March 2026. Each brand has its own page with the reading, the method, and what the method cannot tell you.
| Brand | Container | Reading | Signature |
|---|---|---|---|
| Dasani | Plastic bottle | 143 — highest of the seven | PET |
| Liquid Death | Aluminum can | 141 — second highest, effectively tied with Dasani | PET |
| Path | Aluminum can | 106 — lowest of the seven | PET |
| Crystal Geyser | Plastic bottle | Positive (not scored) | PET |
| Fiji | Plastic bottle | Positive (not scored) | PET |
| Evian | Plastic bottle | Positive (not scored) | PET |
| San Pellegrino | Glass bottle | Positive (not scored) | PET |
The reading is a fluorescence signal strength from particles consistent with plastic — not a particle count. Higher means a stronger signal. Three brands tested positive without being assigned a number this round; we will not rank those three against each other on data we do not have.
The useful finding is not the ranking. It is that the range is narrow, from 106 to 143, and that the container type predicts nothing. A $1 plastic bottle, a $4 aluminum can sold on an anti-plastic platform, and a glass bottle of Italian mineral water all returned the same PET signature.
Switching brands on the strength of a 37-point spread in a screening assay would be reading far more into these numbers than they can carry. If the container is the source, the brand on it is close to irrelevant.
Read the full study — how we identified the plastic type without a $50,000 spectrometer, and why the can linings gave us the result that surprised us most — in We Tested 7 Bottled Water Brands for Microplastics.
Of the seven brands we screened, Path produced the lowest reading at 106. Every brand still tested positive for a PET signature, so "least" means the lowest particle load we measured, not microplastic-free. The spread between the lowest and highest brand is narrow enough that we would not tell anyone to switch brands on the strength of it.
Of what we tested, Dasani produced the highest reading at 143, with Liquid Death a statistically uninteresting 2 points behind. There is no clean option in this group — only degrees of signal, and the container is the common thread.
Not in our screening. Liquid Death and Path both come in aluminum cans, and both returned the same PET signature as the plastic bottles. Every aluminum beverage can has a thin polymer lining to keep the metal from reacting with the liquid. Your water is still sitting against plastic.
San Pellegrino, the one glass bottle in our group, still tested positive for a PET signature. We do not have an explanation we would stand behind. A lined cap, the bottling line, and background contamination in our own workflow are all live possibilities, and one screening round cannot separate them.
Nile Red fluorescence staining, a method adapted from published research. The dye binds hydrophobic material, which glows under specific wavelengths. It is a screening method, not chemical confirmation — Nile Red stains lipids and organic debris as readily as plastic, which is why every result is reported as particles consistent with microplastics rather than as confirmed plastic.
All brand names are registered trademarks of their respective owners. The Water Map is not affiliated with, endorsed by, or sponsored by any of them. Brand names are used only to identify the specific products tested. Every product was purchased at retail, at our own expense.
These are results from an ongoing study, not a peer-reviewed paper. Nile Red is a screening method, not chemical confirmation. Our full list of known limitations is at thewatertest.com/limitations.