Q: Is it really worth buying a reusable bottle? How many times do I have to use it to start saving money and reducing my impact on the environment?
A: The debate over reuse vs. single-use applies not only to water bottles but to many other household products, like plates, cutlery, and towels as well.
The short answer is yes. A reusable bottle will save materials, fuel, and money when compared to disposable water bottles. However, the exact amount of cycles necessary to achieve the savings varies based on a whole host of complex factors. A cradle-to-grave assessment, however, can help you think more systematically about materials analysis and separate fact from fiction.
In your materials impact assessment, you can consider the resources required in terms of raw material extraction, materials processing, manufacturing, labor, distribution, use, repair/maintenance, and disposal/recycling. In this case, you would consider the source of the plastic, extrusion of the material, labor inputs, source of the water, transportation from water source to distribution hub, cleaning, and disposal and/or recycling resources. Numerous academic and industry studies have been published on these comparisons and are easily accessed via the Web. Some, like this University of Michigan publication, provide straightforward summaries.
Financially, the calculations are much simpler. Over the course of a year, the average American is likely to spend $588.00 on 168 bottles of water. Consider, for instance, my 32 oz. Nalgene water bottle, which cost $9.99. Purchasing a one-liter Aquafina bottle on campus costs $2.12. So, I started saving after refilling my bottle five times. Of course, if I had received a free water bottle from the Office of Sustainability, my savings would have begun to accrue immediately.