What Bottled Water Actually Contains (You May Be Surprised)

When PepsiCo launched Aquafina in 1994, it was tapping into something more powerful than thirst. It was selling confidence. The blue label, the crisp branding, the name suggesting mountain springs and glacial purity -- all of it communicated something that municipal tap water, arriving through old pipes into a plain glass, simply couldn't compete with on feeling alone [1].

By 2021, Americans were spending $16 billion a year on bottled water. In 2022, it surpassed carbonated soft drinks to become the best-selling packaged beverage in the United States.

Here's what many bottled water drinkers don't know: Aquafina is purified municipal tap water. So is Dasani, made by Coca-Cola. So is Nestle Pure Life. The word 'purified' on the label is the tell -- it means the water was filtered from a municipal supply, not drawn from a pristine source. Spring water must come from a natural underground spring, but the regulatory definition is less stringent than the marketing suggests.

None of this means bottled water is dangerous. What it does mean is that the premium you're paying isn't necessarily buying you cleaner water -- and the independent testing that has been done on popular brands suggests you may be getting more than you bargained for [2].

Bottled water in the US is regulated by the FDA, while tap water is regulated by the EPA. The two systems sound equivalent; in practice, they're quite different [2].

Municipal water utilities must test water hundreds of times per month, report results publicly in annual Consumer Confidence Reports, and meet enforceable EPA standards. Bottled water companies test their product under FDA oversight -- but the FDA's resources for food safety inspection are vastly smaller than the EPA's water program, and bottled water plants are inspected on average once every few years.

A 1999 NRDC study tested 103 brands of bottled water and found that about one-third violated enforceable standards or exceeded non-enforceable guidelines for bacterial contamination or chemical purity [2]. More recent independent testing has found arsenic at levels exceeding California's strict limit in several brands, phthalates (from plastic packaging), disinfection byproducts, and in some cases microplastics at higher concentrations than tap water.

Spring water has a natural source -- but natural sources can contain naturally occurring contaminants including arsenic, nitrates, and radon. The source water for spring water bottlers is not necessarily tested more rigorously than municipal supplies; in some cases, it is tested less.

The water inside the bottle is only part of the story. The bottle itself contributes to what you drink [3].

Most disposable water bottles are made from PET (recycling code 1). PET is generally considered stable, but research has found that temperature, UV exposure, and time all affect how much it leaches into water. Bottles left in hot cars, stored for extended periods, or reused repeatedly show higher levels of leaching than fresh bottles stored in cool, dark conditions [3].

A 2019 study found that antimony -- a heavy metal used as a catalyst in PET manufacturing -- leaches from PET bottles at levels that increase with storage time and temperature. Car interiors routinely exceed 55 degrees Celsius in summer, which is the threshold where antimony leaching accelerates significantly [3].

Phthalates are endocrine-disrupting chemicals used as plasticisers in some plastic types. Their presence in some bottled water samples has been documented. And some polycarbonate water cooler bottles (the large 5-gallon jugs) contain BPA, a well-documented endocrine disruptor -- though as we explore elsewhere, some BPA replacements (BPS, BPF) have similar biological activity.

The environmental arithmetic of bottled water is genuinely unflattering [1].

Producing a single litre of bottled water requires approximately 3 litres of water in manufacturing plus water to produce the plastic bottle itself. The energy required to produce, fill, and transport bottled water is estimated to be 1,000-2,000 times greater than the energy required to deliver the equivalent volume of tap water [1].

Americans use about 50 billion plastic water bottles per year. Roughly 80% end up in landfills or the environment rather than being recycled. PET recycling rates have been declining as the plastic fraction in municipal waste streams has become more contaminated. A significant fraction of 'recycled' plastic is shipped overseas, where its ultimate fate is often unclear.

A high-quality home water filter -- even a certified pitcher filter -- produces water that meets or exceeds bottled water safety standards at a fraction of the cost and a tiny fraction of the environmental footprint. At typical bottled water prices, a household spending $50-150/month on bottled water would pay for a high-end reverse osmosis system within months.

There are legitimate uses for bottled water: during boil-water advisories, when travelling in areas with unsafe tap water, and in emergency preparedness. For everyday household hydration in a home with municipal water access, bottled water is neither safer nor more environmentally responsible than filtered tap water.