We know that plastic is bad for nature, rivers, lakes, and oceans but what’s the environmental impact beyond this? What is the carbon footprint of manufacturing of plastic, filling the bottles, transportation, and end-of-life depositing or recycling?
If you search online you will find a wide range of articles on this topic but most are either very academic or just refer to one study. Some of them are published by the bottled water industry and thus not entirely objective. Others are by the glass bottle producers with a completely different take.
In this article we summarize the key studies to give you a range of what the CO2 footprint of bottled water is depending on who you believe and how you count.
What is Carbon Footprint?
Carbon footprint (or CO2 footprint) is defined as the total emissions caused by an individual, event, organization, or product, expressed as carbon dioxide equivalent. Although there are established standards for calculating the CO2 footprint in manufacturing, transportation, agriculture, etc there are also great levels of uncertainty. This is one reason that the results of studies vary so widely. Another reason is that they are often partial based on the interest of the group presenting the results.
Summary carbon footprint of bottled water
Want to know the high-level data and not all the details?
Here’s a table with a high-level overview from the lowest to highest estimates and medium of bottled water CO2 footprint. We've tried to illustrate the CO2 footprint by comparing it to cars and the total global carbon footprint.
| Variable | Low | Medium | High |
|---|---|---|---|
| CO2 footprint per 50 oz (1.5 liter) bottle cradle-to-cradle | 1.6 ounces (44 g) | 9 ounces (250 g) | 22 ounces (633 g) |
| CO2 footprint total bottled water | 31 billion pounds (14 billion kg) CO2 | 176 billion pounds (80 billion kg) CO2 | 446 billion pounds (203 billion kg) CO2 |
| Equivalent in distance driven by a car* | 52 billion miles (84 billion km) | 298 billion miles (480 billion km) | 757 billion miles (1,218 billion km) |
| Equivalent in number of cars** | 5 million cars | 29 million cars | 74 million cars |
| % of total CO2 released globally per year*** | 0.038% | 0.21% | 0.54% |
* Using 6 km / kg CO2 which is the average between US and Europe
** Using average of 10,200 miles per year which is the average of (Europe 10,816 km per year) and (US 13,746 miles per year)
*** Global Carbon footprint 2017 was 37 billion tons
About the CO2 footprint studies of bottled water
Based on the most cited study it’s about 0.5 lbs (200 g) per 50 ounces (1.5 liters) bottle which means that 800 bottles per year consumed by the average bottle-drinking household is equal to 350 lbs (160 kg) CO2 or the equivalent of driving 368 miles (592 km) with a car. But the range of estimates of CO2 footprint per bottle is from 1.6 ounces (44g) to 23 ounces (663g). The more recent studies are in the higher range.
The studies all differ when it comes to the exact breakdown. Some include cradle-to-cradle (from material to end-of-life waste) and others focus on the materials and manufacturing. Neither of them included transportation to the end consumer in the total measure. Therefore we first summarize the total CO2 footprint from the studies and then break down the components.
We’ve generally used the original measures of the studies which is why the tables include a mix of metric and imperial measurements.
Total CO2 footprint of bottled water excluding transport
We included the most cited/referenced studies in this analysis. Some were also excluded due to a lack of data backing up the research.
We used a 50 ounce (1.5 litre) bottle as a benchmark as this is the most common size water bottle bought in supermarkets. However, it could just as well be argued that we should use the smaller bottle size served in kiosks, coffee shops, and major transportation hubs. Anyone can easily translate these metrics into smaller bottle sizes for comparison.
| Study | CO2 footprint per bottle | Calculation |
|---|---|---|
| Water footprint network summarised on sciencing.com | 199g | 82.8g x 3 * 80% = 199g |
| EPA | 44.1g | 1.95g x 75% (1.5l) x 28.3g (1 ounce) = 44.1g |
| Science Direct | 45.3g | 1.95g x 75% (1.5l) x 28.3g (1 ounce) x 1.538 x (29%+30%+8%) = 45.3g |
| UWISC | 560g | 280g per 750ml PET bottle x 2 (for 1.5l) = 560g, includes transportation |
| Natureworks EU | 94.5g | 2.15 kg CO2 per kg PET = 94.5g |
| Natureworks US | 120g | 2.73 kg CO2 per kg PET = 120g |
Total CO2 footprint of plastic bottles compared to glass and aluminium
In our research, we only found one peer-reviewed comparison study of plastic bottles to glass and aluminium. Although credible it should be noted in advance that it's by a glass bottle manufacturer.
It would also be interesting to compare to paper cartoons such as tetrapak water bottles that are coming more common. Especially since these also contain plastic film making them difficult to recycle.
OI split the breakdown in US and European bottles due to primarily the sourcing of material but also the mix in energy production. The US had a higher CO2 footprint on all measures.
Based on bottling in the US
| Study | CO2 footprint per bottle | Notes |
|---|---|---|
| OI – PET | 633g | 214g per 355ml x 4.2 x 70% = 633g, assumption that total footprint of a 1.5l is 70% less per 0.355l = 4.2x |
| OI - Glass | 503g | 171g per 355ml x 4.2 x 70% = 503g, same as above |
| OI – Aluminium | 1604g | 401g per 355ml x 4 = 1604g, 4 cans |
| OI - Glass refill | 24g | 6g x 4 = 24g, assumes each bottle is reused 30 times |
Based on bottling in Europe
| Study | CO2 footprint per bottle | Notes |
|---|---|---|
| OI – PET | 447g | 152g x 4.2 x 70% = 447g |
| OI - Glass | 323g | 110g x 4.2 x 70% = 323g |
| OI – Aluminium | 488g | 122g x 4 = 488g |
| OI - Glass refill | 24g | 6g x 4 = 24g, assumes each bottle is reused 30 times |
Notes:
Glass - Only a few countries have glass bottle deposit and recycling schemes, which means they are only used once and then recycled as glass.
Transportation - The studies we found all excluded transportation of bottles to the end consumer as this depends so much on the brand. Therefore you need to add transportation on top of these figures.
Manufacturing of PET incl transportation of raw materials
Transporting the raw material including mainly oil to start with and the production of the plastic resins used to produce bottles contribute to a bottle's carbon footprint in a major way.
| Study | CO2 footprint | Notes |
|---|---|---|
| Water footprint network summarized on sciencing.com | 133g | 82.8g per 0.5l of PET bottled water whereof: Transportation of raw materials: 29%, Plastic resins: 30%, Creating the bottle: 8%. The assumption is that the total footprint of 1.5l is 80% less per 0.5l. |
What is the CO2 footprint reduction from recycling
Recycling can reduce carbon dioxide and other greenhouse gasses by an estimated 30 to 70 percent. Based on the breakdown it looks more likely to be 30%. Today only about 10-20% of water bottles are made out of recycled PET in Europe and North America.
Filling, packaging, and storing the bottle
Filling the bottles, packaging, and storing the bottles prior to distribution also contributes to the total CO2 footprint of plastic bottles. Storage in refrigerators for longer periods of time could be a major carbon dioxide contributor.
| Study | CO2 footprint | Notes |
|---|---|---|
| Water footprint network summarized on sciencing.com | 82.8g per 0.5l of PET bottled water whereof: 33% | (33%) x 82.8g x 3 *80% = 66g The assumption is that the total footprint of 1.5l is 80% less per 0.5l. |
The CO2 footprint of transporting bottled water
Transportation of bottled water is another big cause of carbon footprint due to the great distances some bottles travel. Fiji water for example may travel as far as 9050 miles (14,500 km) to reach a consumer in the United States. Even most locally produced bottled water travels a great distance due to the transportation hubs used by e.g. Walmart to distribute the water to stores.
We found surprisingly few studies on the transportation of bottled water beyond news articles about Fiji water from 2007.
One of the more extensive studies looked at 8 bottled water brands in Italy and concluded that the carbon footprint of transporting bottled water locally in Italy is 300 times that of tap water. Italy generally has good tap water but Italians love bottled water almost as much as they love a good espresso. The brands put great pride in the source, content, taste, and design of the bottle.
But local consumption of bottled water is at least better than shipping premium bottled water around the globe. This is also an example where glass bottles are actually worse than plastic bottles due to weight and volume.
How do we calculate the CO2 footprint of transporting bottled water?
Calculating the CO2 footprint of bottled water is relatively easy thanks to the fact that the weight of 1 liter of water is close to 1 kg. Using the standard measures defined by ECTA Alan McKinnon we can then multiply this by the metric tonne per kilometre.
The mean of transportation makes a big difference as the ship is more efficient than trucks. For example:
- A ton of Tasmanian rainwater traveling 7938 miles by ship uses 15.44 gallons of fuel and emits 342.77 pounds of CO2.
- A ton of Poland Springs going by truck traveling 1141 miles from Maine to Chicago uses 16.54 gallons of fuel and emits 367.19 pounds of CO2.
But the reality is that the Tasmanian rainwater will also be transported by the equivalent miles on a truck to reach the consumer.
| Study | CO2 footprint | Notes |
|---|---|---|
| ECTA Alan McKinnon | Ship: 8.4 g CO2/tonne-km Truck: 62g CO2/tonne-km |
Local Water: 47g International: 375g |
Example: Local water
Assuming an average shipping distance of 312 miles (500 km) by truck it’s about 31g per liter or 47g per average bottle.
Example: International Water (Fiji Water)
The transport distance from Fiji to the center of the United States is 7800 miles (12,500 km) in bird distance translating to an average of about 944 miles (15,000 km) by ship and 1250 miles (2,000 km) by truck. This means 126 kg + 124 kg per ton = 250 kg or 250 g per liter and 375g per average bottle. (Note: Fiji normally comes in 0.5 l bottles so not an entirely fair comparison).
What is the carbon footprint of tap water?
The CO2 footprint of tap water comes from pumping it up from the ground or surface water, treating it for drinking, and pumping it into the water pipes to reach the consumer. Multiple comparison studies have shown that the carbon footprint of tap water is about 1/300 or 1/1000 compared to bottled water. The most cited is an Italian study summarized in Nature.
What is the CO2 footprint of the TAPP Water filters?
We started this article by mentioning that the carbon footprint can be a measure of any product. However, calculating it can be extremely complicated and water filters are no exception.
TAPP Water is still pending the completion of a cradle-to-cradle study of our product that would pass the scrutiny of academics. Until this is finalized we’ve done a back-of-the-envelope calculation to estimate the carbon footprint of EcoPro.
Calculation of EcoPro CO2 Footprint
The filter weighs approximately 923 g including one cartridge. Each cartridge weighs approximately 365 g.
Our assumption is that the Cradle-to-Cradle CO2 footprint of EcoPro and EcoPro refill cartridges is about the same as a PET bottle with mineral water shipped internationally per kg. This is a rough assumption since the product in addition to ABS plastic consists of PLA plastic, a stainless steel connector but the materials, raw material transportation, production method, and transportation to the customer are about the same on average. The Cradle-to-Cradle CO2 footprint of PET bottles is about 1.5 kg to 3 kg depending on the source. ABS plastics have a CO2 footprint of 1.4x PET but on the other hand, PLA has a CO2 footprint of 1/4 vs PET. This means the carbon footprint of the plastic part of EcoPro should actually be less than PET. The other materials make up less than 20% of the total weight/material.
Based on this assumption and the weight of EcoPro including packaging the CO2 footprint of a EcoPro filter is about 2 kg including filter and 4 refill cartridges.
The average customer consumed 2 bottles of water per day prior to installing EcoPro. This means 730 bottles per year. The average cradle-to-cradle CO2 for a bottle is about 200 g to 633 g depending on which study is used. This is 146 kg to 456 kg CO2 per year compared to EcoPro of 2 kg. This is a saving of over 98%.
In addition to this TAPP Water uses recclable cartridges made of ABS. EcoPro Compact refills contain no plastic at all.
What is the CO2 footprint of a refillable bottle?
Refillable bottles are a great way of staying hydrated while avoiding buying bottled water. Especially bottles that last for years.
Since we plan to launch a new refillable bottle we will be calculating the CO2 footprint of refillable bottles ourselves.
In the meantime, the University of Wisconsin has done a pretty good general study on the topic.
Summary
Recent estimates of CO2 emission from bottled water have resulted in higher estimates than before. This means that the problem is even worse than we imagined.
With approximately 480 billion plastic bottles consumed in 2018 with an average size of 1 liter, this means that the CO2 footprint was between 67 billion and 192 billion kg of CO2 per year. That is the equivalent of
- Driving 248 to 710 billion kilometers by car or the annual CO2 output of about 5 to 74 million cars.
- The entire yearly CO2 footprint of a nation like Greece (72 billion kg) or the Netherlands (175 billion kg) in 2017.
- Up to one-third of the entire aviation industry (543 billion kg)
And this is just part of the problem with bottled water. Other issues include plastic pollution, microplastics, water waste, and where the water is sourced.
Note: The CO2 amount released is assumed to be 1 kg CO2 per 2.4 miles (4 km) in an average US car) and 5 miles (8km) for Europe. We, therefore, use 6 km as an average.
Sources:
Sciencing article: Carbon footprint of plastic bottles
https://sciencing.com/carbon-footprint-plastic-bottle-12307187.html
Pacific Institute: Carbon Footprint of Bottled Water
https://iopscience.iop.org/article/10.1088/1748-9326/4/1/014009/pdf
Stanford: Carbon footprint of bottled water
https://alumni.stanford.edu/get/page/magazine/article/?article_id=30619
Science Direct 2013: Carbon footprint analysis in plastics manufacturing https://www.sciencedirect.com/science/article/pii/S095965261300019X
Natureworks study on PLA vs PET, ABS, PP and other plastics: https://www.environmentalleader.com/2015/07/
OI validated by AMR research: Complete look at carbon footprint from glass packaging
https://www.easyfairs.com/uploads/tx_ef/y.agniel_global_engineering.pdf
University of Wisconsin: Carbon footprint of refillable bottled water vs bottled water
https://sustainability.wisc.edu/refillable-water-bottles-research-in-progress/
US Massachusetts’s University study on carbon footprint of bottled water:
http://www.mwra.state.ma.us/
Nature: Carbon footprint comparison of tap water and bottled water
http://precedings.nature.com/documents/3407/version/1
Dieselnet: CO2 emission for European cars by country:
https://www.dieselnet.com/news/2019/03jato.php
EPA: CO2 emission for American cars:
https://www.epa.gov/greenvehicles/greenhouse-gas-emissions-typical-passenger-vehicle
Truck emission:
https://www.transportenvironment.org/
ECTA Transport emission:
https://www.ecta.com/
Study of carbon footprint of 8 Italian bottled water brands compared to tap water:
https://core.ac.uk/download/pdf/288584.pdf
