Re-use you PET-bottles and refill them with tap water. Don't buy bottled water unless you live in a city/country where you might need to. Reuse the bottles if possible.

Here's an simple model to make it more trendy and fun to carry around a bottle of water. It's also remarkable fun to play with the bottle (spinning it around etc.)

See and share more things related to 3D-printing at home or for personal use here: https://www.facebook.com/groups/217383965277249/