Bottled Water: Myths vs. Facts

We’ve spent a lot of time and energy lately looking into the bottled water industry and how bottled water quality compares with tap water quality. (Read the results of our peer-reviewed bottled water study). We’ve found that there are loads of misconceptions when it comes to bottled water and we’d like to pin them down as myths or facts once and for all.

Various studies have shown cases where bottled water in the U.S. contained a wide range of contaminants, including bacteria, heavy metals including lead and antimony, arsenic, volatile and semi-volatile organic contaminants, disinfection by-products, radiological elements, microplastics, and many PFAS compounds.[1-11] In our own study of 100 different bottled water products from the Bay Area in 2022 (full results to be released soon), we found many of these contaminants ourselves, including: lead, antimony, chromium, vanadium, arsenic, benzene, toluene, trihalomethanes, uranium and heterotrophic bacteria, among others.

While contaminants are not typically present in bottled water in concentrations exceeding state or federal regulations, both a 2011 Environmental Working Group (EWG) study and our own study found multiple products with total trihalomethane concentrations in exceedance of California’s regulatory limit–two products in the EWG study and five products in our study.[2] We also compared contaminant concentrations to health-based benchmarks (rather than regulatory standards alone, which incorporate financial considerations) and found that 17 contaminants detected in the bottled water products exceeded health-based benchmarks among the 100 products we tested. These health-based benchmarks are very conservative–they indicate an increased risk of disease if the water is consumed over a lifetime–and shouldn’t be viewed as a guarantee of illness or an immediate danger.

First, bottled water and tap water are regulated at the federal level by two different entities–tap water is regulated by the Environmental Protection Agency (EPA), while bottled water is under the purview of the Food and Drug Administration (FDA). Allowable concentrations of individual contaminants in bottled water are required to be set at levels that are “no less stringent” than the allowable concentrations in tap water.[12] However, the maximum allowable concentrations of contaminants in the finished product is only one aspect of the regulations governing bottled water quality.

Bigger differences between bottled water and tap water regulations become apparent when it comes to monitoring and enforcement. Bottled water manufacturers are required to do regular testing of their source water and products, but they are not required to use State certified laboratories to analyze their samples. In fact, many bottlers do their testing at their own in-house labs and it is very rare for the FDA to take samples to independently confirm the results from the bottler’s lab. In general, FDA inspections are rare and typically focus on conditions at the bottling plant rather than water quality. In addition, contaminant standard violations are not required to be reported to the FDA or the public, the only requirement is that the label state that the product “contains excessive [contaminant]”.[11][13]

In contrast, the EPA requires regular testing of tap water by certified laboratories as well as regular reporting to state or federal officials.[14] Violations of contaminant standards must be reported to the public quickly and immediate action is required, and water agencies are required to send detailed water quality reports to all of their customers annually.[15][16]

• MYTH: Bottled water is just tap water. However…
• FACT: Many bottled water products start out as tap water. 

A significant fraction of bottled water products start out as plain old tap water. These products almost always undergo further treatment using common technologies that are available in home water treatment devices, such as activated carbon, reverse osmosis and ion exchange. These products are typically labeled as ‘purified’ water.[13] Though it’s technically acceptable for bottled water to be sourced from tap water without additional treatment, it’s exceedingly rare (and we’ve never seen it ourselves).

As mentioned, bottled water is regulated as a food product by the FDA. Accordingly, the labels on bottled water products are only required to disclose any added ingredients, but are not required to disclose information about the inherent water quality.[13] So for a bottled water that didn’t add any ingredients (for example, fluoride or minerals for taste), there is no need for any further information to be disclosed on the label. Many bottled water products direct you to a phone number or a website where more information may be available, but it’s not required by law that manufacturers release water quality information. 

In fact, one of the only times bottled water manufacturers are required to divulge any information regarding water quality on their labels is in the event that a water quality standard has been violated–in this case, they must include the statement “contains excessive [contaminant in violation]” on the label. As you can imagine, due to somewhat infrequent testing, the chances that violations are caught before labeling are vanishingly low.

As a point of comparison, utilities must release water quality reports to all customers annually regarding the quality of their tap water. They are also required to issue public notifications when water quality standards are not met or even if a system failed to test its water.[15]

This is absolutely true, no matter which type of bottled water you buy, even if you buy it in bulk. There are many different estimates out there for price differences so we’ll walk through one right now. We’ll use 2020 as our model year due to the availability of bottled water information.

TAP WATER: The average cost of tap water in 2017 was $0.0034/gallon–this is excluding the fixed fees and sewer fees.[17] If we assume a 4% cost increase per year, the average cost in 2020 would have been $0.0038. It is recommended that people drink 8 cups, or ½ gallon, per day so, for a family of four, this would be 2 gallons/day which is 182.5 gallons/year (this is for drinking only, we’re excluding water used for other purposes like cooking, showering, watering your lawn, etc). At $0.0038/gallon, the total cost of drinking water for a family of four in 2020 would have been approximately $2.80 for the year, so let’s round up to about $3.  Note that this won’t be the number you see on your bill at the end of the year because of all of the other water used in a day as well as fixed fees and sewer charge.

BOTTLED WATER: The cost of bottled water can vary considerably. Here, we will focus on single serving (500 mL) PET bottles as they make up the majority of the bottled water market (~70% in 2020).[18] The costs of these single serving bottles can vary wildly, as well–you can buy store brand water bottles in 48 packs, more high end products (e.g., Evian) individually, and everything in between. 

According to the Beverage Marketing Corporation, the average wholesale price of bottled water in 2020 was $1.17/gallon.[19] The average markup for bottled water is 50-200%–we’ll assume a 100% markup, bringing the cost per gallon to $2.34.[20] Assuming the same consumption patterns as above for tap water, the cost of bottled water for a family of four for a year would be approximately $1,708, which is about 610 times the cost of tap water! This number rises significantly (up over 3,000 times the price of tap water) if you are purchasing individual bottles.

To think a little more deeply about this cost comparison, we thought it would be useful to look at the cost of treating your tap water at home as a replacement for buying bottled water.

PITCHER FILTER: Pitcher filters typically contain activated carbon and often include additional technologies, like ion exchange. They are usually used to reduce taste and odor issues and sometimes to remove specific contaminants, like disinfection byproducts and lead.

A typical pitcher costs around $30 and we’ll assume you use it for at least 5 years–this cost ends up being about $6/year. Replacement filters typically cost around $30/year. So adding in the cost of water that we determined above ($2.80) to the pitcher and the filter replacements, treating your water with a pitcher filter for a family of four for a year costs about $39.

REVERSE OSMOSIS: One of the more comprehensive treatment systems you can have at home is a reverse osmosis (RO) system. Most RO systems are multi-stage and typically include an activated carbon step. These systems will reduce most contaminants that could be present in drinking water.

An average point-of-use RO system costs around $300 and we’ll assume you use it for 10 years–this cost ends up being about $30/year. Replacement filter cartridges typically cost around $75. Adding in the cost of water, water treated via RO for a family of four for a year costs about $122. This is the most expensive of the tap water options, but still much cheaper than buying bottled water.

All in all, bottled water is much more expensive than tap water any way you look at it.

• FACT: Bottled water production is detrimental to the environment.

It is objectively true that bottled water production is environmentally harmful. Here’s a quick rundown of some very high level facts. For context, 70% of the bottled water market in 2020 was made up of products individually packaged in polyethylene terephthalate (PET) bottles.[21]

• Only about 1 in 5 PET bottles are recycled and used as material for other products–4 in 5 end up in landfills or elsewhere.[22]

• Plastic bottle caps and bottles are the 2nd and 3rd most common items found in the ocean, respectively.[23]

• Manufacturing PET releases various toxic air pollutants, including volatile organic compounds, sulfur oxides, nitrogen oxides, and antimony.[24]

• Though recycled PET consumes fewer resources than manufacturing virgin PET, the recycling process itself uses water and energy, and results in the emissions of air pollutants.[25]

• Producing the 70% of bottled water products that are individually sold in PET bottles uses somewhere between 22 and 52 million barrels of oil (mainly depending on how far the product was transported).*

*using embedded energy estimates from Cooley and Gleick [26], estimated mass of 8.3 g/bottle from IBWA [27]