Yes, when you first purchase bottled water, you must purchase an empty barrel. This is because bottled water is generally sold in empty buckets rather than filled directly with water. When you first buy bottled water, you need to buy an empty bucket and pour the water into the bucket. For future purchases, you can choose to purchase a full bucket of water directly, or you can choose to bring an empty bucket yourself for reuse.
Also, depending on the regulations of some bottled water suppliers, if you choose not to purchase empty barrels, you may be required to pay an additional deposit. Therefore, in order to reduce costs and avoid unnecessary trouble, it is recommended to purchase an empty barrel when purchasing bottled water for the first time.