Let me show you how to track your empty water bottles.
The answer is yes. QuickBooks Online has an inventory feature so you can properly track them. If you haven't yet, you can follow these steps to turn it on.
Go to the Gear icon and select Account and Settings.
From the Sales tab, select the Products and services section.
Turn on both the Show Product/Service column on sales forms, Track quantity and price/rate, and Track inventory quantity on hand.