EWG's Bottled Water Scorecard, 2011: Methodology
Environmental Working Group (EWG) analyzed the labels and websites of 173 bottled water products to determine if the industry has heeded repeated calls to disclose basic facts about their products - the water's specific geographic source, treatment methods and purity. We also investigated the industry’s compliance with California’s labeling disclosure law, SB 220. Details on label acquisition and analysis as well as the scoring matrix used to rate bottled waters for transparency are provided below.
In March 2010, EWG invited the public via common social media outlets to submit the labels of bottled waters they had purchased. Between March and September 2010 we received 274 unique labels for 173 different bottled water products. Many products bore multiple unique labels; we found that label content varies state-to-state and even within a state and can vary with the bottle size. Overall, the products we assessed were purchased in 29 states, led by California with 111 labels from 96 products.
EWG researchers constructed a database containing label details regarding water source, treatment and testing. We also recorded the location and date of product's purchase, as well as any production and/or expiration dates that were available. We recorded similar source, treatment and testing data available from company websites.
EWG researchers analyzed the information in the database and scored each product based on: 1) transparency as indicated by disclosure of the water's source location, purification and testing information on both the product label and the company website, 2) the efficacy of purification methods used to treat the water and, for waters purchased in California, 3) the degree of compliance with SB 220.
Scoring system — EWG's method of rating bottled water
EWG's rating system considers three components: transparency (completeness of information on the label and website about water's geographic source, treatment and purity); efficacy of purification methods used to treat the water; the product's compliance with California's bottled water disclosure law, SB 220. Each of these components is described below.
The tables below detail the factors EWG used to rate the transparency bottled waters.
|Label Details||Website Details|
|Precise geographic source name and location||2 pts||1 pt|
|Multiple, specific source names and locations listed as possibilities||1.5 pts||0.75 pt|
|Partial or vague1||1 pt||0.5 pts|
|Product name is the only indicator of source||0.5 pts||0.2 pts|
|None listed||0 pts||0 pts|
|No website||---||0 pts|
|Treatments named/Lack of treatment disclosed||2 pts||1 pt|
|Partial or vague2||1 pt||0.5 pts|
|Product name is the only indicator of purification||0.5 pts||0.2 pts|
|None listed||0 pts||0 pts|
|No website||---||0 pts|
|Statement on label with information about obtaining a water quality report||1 pt||---|
|Water Quality Report available||---||0.5 pts|
|Report lists full SDWA* contaminant list||---||0.5 pts|
|Report lists partial SDWA* contaminant list||---||0.2 pts|
|Report includes complete documentation of all chemicals tested for||---||0.5 pts|
|Report only includes partial documentation of all chemicals tested for||---||0.2 pts|
|Report represents the most current water quality data||---||0.5 pts|
|Report is either a "typical" analysis or is undated||---||0.2 pts|
- 1Partial or vague source information refers to products that do not disclose specific geographic source names and locations. Examples include phrases such as "deep within Michigan's countryside" and "a deep pristine crystalline rock aquifer".
- 2Partial or vague purification information refers to products that do not make clear the treatment processes used, or the lack thereof. An example is the phrase "state of the art ultra-purification system" with no further clarification.
- *SDWA- Safe Drinking Water Act: "The Safe Drinking Water Act (SDWA) is the main federal law that ensures the quality of Americans' drinking water. Under SDWA, EPA sets standards for drinking water quality" (EPA, 2009).
We assigned a transparency score to each bottled water product by summing the individual scoring components listed above. The transparency score was adjusted by scores that considered purification efficacy (subtracting points where advanced treatment processes, such as reverse osmosis and distillation, were not applied) and by scores considering compliance with SB 220, to calculate each product's final score.
Scores for compliance with SB 220
EWG assessed a product's compliance with SB 220 based on two factors: 1) compliance with the law's labeling requirements; and 2) whether or not we were able to acquire a water quality report from the contacts listed on the product label.
|Consumer Confidence Report Compliance|
|WQRs Available from Both Contacts||0 pt|
|WQRs Available from Only One Contact||-0.25 pt|
|WQRs Not Available from Any of the Listed Contacts||-0.5 pt|
|Fully Labeled||0 pts|
|Partially Labeled||-0.25 pts|
|Label Included No Source and No Contacts||-0.5 pt|
Scores for efficacy of purification method
EWG rated the efficacy of purification techniques using the scheme detailed below. Waters treated with advanced purification techniques received higher scores in our rating system.
|Advanced Treatment Used||0 pts|
|Basic Treatment Used||-0.5 pts|
|No Treatment Used/None Listed||-1 pt|
Letter grade key
We represented the overall score as a letter grade based on the key below.
|A||8.6 - 10.0|
|B||6.9 - 8.5|
|C||5.0 - 6.8|
|D||2.9 - 4.9|
|F||1.0 - 2.8|
EPA (U.S. Environmental Protection Agency). 2010. Safe Drinking Water Act (SDWA). Available: http://water.epa.gov/lawsregs/rulesregs/sdwa/index.cfm [accessed October 5 2010].